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Sexually Transmitted Disease Gallery

Bacterial vaginosis

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  This photomicrograph of a vaginal smear specimen depicts two epithelial cells, a normal cell, and an epithelial cell with its exterior covered by bacteria giving the cell a roughened, stippled appearance known as a “clue cell”. Clue cells are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

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  This photograph depicted a single Gardnerella vaginalis, formerly Haemophilus vaginalis, or Corynebacterium vaginalis, bacterial colony. The vagina is normally colonized by Lactobacillus spp., which help to regulate the region’s pH, maintaining it in the low range, thereby, inhibiting the growth of potentially-pathogenic organisms. The Gram-positive Gardnerella vaginalis bacterium is one such organism, and is a common cause for bacterial vaginosis (BV). Adapted from CDC

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  This photograph depicted a single Gardnerella vaginalis, formerly Haemophilus vaginalis, or Corynebacterium vaginalis, bacterial colony. The vagina is normally colonized by Lactobacillus spp., which help to regulate the region’s pH, maintaining it in the low range, thereby, inhibiting the growth of potentially-pathogenic organisms. The Gram-positive Gardnerella vaginalis bacterium is one such organism, and is a common cause for bacterial vaginosis (BV). Adapted from CDC

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  This photomicrograph reveals bacteria adhering to vaginal epithelial cells known as “clue cells”. “Clue cells” are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

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  This photomicrograph reveals bacteria adhering to vaginal epithelial cells known as “clue cells”. “Clue cells” are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

Chlamydia

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  Under a relatively-low magnification of 63X, this Gram-stained photomicrograph of a vaginal specimen revealed the presence of squamous epithelial cells, polymorphonuclear leukocytes (PMNs), or white blood cells (WBCs), and numerous Gram-positive bacilli, or rods. Vaginal specimens are reviewed for many reasons including the Pap test, tests for STDs such as human papilloma virus (HPV) and Chlamydia trachomatis, as well as others. The vagina is normally home to a number of bacterial organisms, referred to as vaginal microbiota, or vaginal microflora, composed primarily of rod-shaped Lactobacillus spp., as well as others. Adapted from CDC

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  Photomicrograph of Chlamydia trachomatis taken from a urethral scrape. Untreated, chlamydia can cause severe, costly reproductive and other health problems including both short- and long-term consequences, i.e. pelvic inflammatory disease (PID), infertility, and potentially fatal tubal pregnancy. Adapted from CDC

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  This McCoy cell monolayer micrograph reveals a number of intracellular C. trachomatis inclusion bodies; Magnified 50X. The intracellular inclusion body represents the replication phase of the Chlamydia spp. organisms, whereupon, the reorganized reticulate body (RB) multiplies through binary fission into 100-500 new RBs, which mature into elementary bodies (EB). Adapted from CDC

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  This image reveals a close view of a patient’s left eye with the upper lid retracted in order to reveal the inflamed conjunctival membrane lining the inside of both the upper and lower lids, due to what was determined to be a case of inclusion conjunctivitis, a type of conjunctival inflammation caused by the bacterium, Chlamydia trachomatis. Inclusion conjunctivitis, also known as chlamydial conjunctivitis, is more common in newborns. Symptoms include redness of the eye(s), swelling of the eyelids, and discharge of pus, usually 5 to 12 days after birth. Adapted from CDC

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  This photomicrograph depicts HeLa cells infected with Type-A Chlamydia trachomatis, Magnified 400X. The cell line of choice is McCoy, however a particular strain of HeLa cells, i.e. HeLa 299-24, can be used to culture C. trachomatis. For identification, either iodine or fluorescent antibody (FA) stains are usually used. Adapted from CDC

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  Under a low magnification of 12.5X, this photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections. Adapted from CDC

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  This photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies; Magnified 50X. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections.Adapted from CDC

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  This photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies; Magnified 200X. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections. Adapted from CDC

Gonorrhea

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  This 1970 photograph revealed the presence of what was determined to be a secondary gonococcal lesion located on the distal finger tip of a patient who presented with a case of gonorrhea. Usually, secondary gonococcal lesions manifest themselves when a primary infection of the urogenital tract becomes disseminated throughout the body by way of the circulatory system.

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  This 1970 photograph revealed the presence of what was determined to be a gonococcal infection involving the cervix of a patient who presented with a case of gonorrhea. Note that there is a purulent discharge emanating from the cervical os, and pooling in the vagina.Adapted from CDC

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  This gonorrhoeae patient presented with gonococcal arthritis of the hand, which caused the hand and wrist to swell due to bacterium Neisseria gonorrhoeae. Adapted from CDC

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  This gonococcal arthritic patient presented with an inflammation of the skin of her right arm due to a disseminated Neisseria gonorrhoeaebacterial infection. Adapted from CDC

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  This patient presented with a cutaneous gonococcal lesion due to a disseminated Neisseria gonorrhea bacterial infection. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations. Adapted from CDC

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  This colposcopic view of this patient’s cervix reveled an eroded ostium due to Neisseria gonorrhea infection. A chronic Neisseria gonorrhea infection can lead to complications, which can be apparent such as this cervical inflammation, and some can be quite insipid, giving the impression that the infection has subsided, while treatment is still needed.Adapted from CDC

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  This patient presented with a lesion of the right hand due to a disseminated Neisseria gonorrhoeae bacteremia. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations.Adapted from CDC

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  This patient presented with urogenital complications from a case of gonorrhea including penile paraphimosis. Due to the accompanying inflammation brought on by the Neisseria gonorrhoeae infection, the foreskin becomes adherent to the glans penis resulting in a condition known as phimosis, and cannot be retracted in order to expose the entire glans. Adapted from CDC

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  This patient presented with a paraurethral abscess due to the spread of N. gonorrhoeae bacteria. In this case, the spread of the bacterial pathogen from its initial urethral site of origin to the surrounding penile tissues brought on the formation of an abscess, which was one of three that had formed in this manner.Adapted from CDC

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  This patient presented with cutaneous foot lesions that were diagnosed as a disseminated gonococcal infection. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

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  This patient presented with a cutaneous lesion that was traced to a systemically disseminated gonoccal infection. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations.Adapted from CDC

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  Here, a specimen is about to be collected from this patient who presented with symptoms including a penile discharge. Most Neisseria and related species are normal flora in humans and animals, however, some species such as N. gonorrhoeae are pathogens in normal hosts and those species known to be commensal, may be opportunistic pathogens. Adapted from CDC

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  This patient presented with a cutaneous lesion on the palm of his right hand due to a N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body. Adapted from CDC

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  His patient presented with cutaneous lesions on his left ankle and calf due to a disseminated N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.

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  This patient presented with cutaneous lesions on the right forearm and left hand due to a N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.

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  This patient presented with ophthalmic inflammation that was diagnosed as gonococcal conjunctivitis. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as cutaneous ulcerations or conjunctival inflammation.

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  A highly contagious infection, gonococcal ophthalmia is due the pathogenic bacteria Neisseria gonorrhoeae. This case involved an adult patient with a systemically disseminated gonococcal infection, but neonates are in danger of acquiring this ophthalmic infection at the time of their delivery when the mother is infected with N. gonorrhoeae bacteria.Adapted from CDC

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  This case of gonorrheal conjunctivitis resulted in partial blindness due to the spread of N. gonorrhoeae bacteria. Gonococci cause both localized infections, usually in the genital tract, and disseminated infections with seeding of various organs. Diagnosis of localized infections depends on Gram-staining, and culture of the discharge.Adapted from CDC

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  The early lesion on this patient’s left index finger was due to the systemic dissemination of N. gonorrhoeae bacteria. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

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  The lesion on this patient’s left hand was due to the systemic dissemination of the Neisseria gonorrhoeae bacteria. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

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  The lesion on this patient’s heel was due to the systemic dissemination of the N. gonorrhoeae bacteria. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

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  Note the cloudiness of this patient's right eye in this case of gonococcal conjunctivitis due to N. gonorrhoeae bacteria. Gonococcal conjunctivitis in caused by a direct inoculation of the conjunctival membrane of the eye with Neisseria gonorrhoeae bacteria, causing this membrane covering the eye to become inflamed, edematous, and produce a purulent exudate.Adapted from CDC

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  This patient presented with a penile meatal discharge which was diagnosed as gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is stripped towards the orifice to express some pus. A thin sterile swab is then inserted 23 cm into the urethra and rotated before being withdrawn.Adapted from CDC

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  This patient presented with a case of gonorrhea with symptoms including cervicitis and vaginal discharge. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

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  This male presented with purulent penile discharge due to gonorrhea with an overlying penile pyodermal lesion. Pyoderma involves the formation of a purulent skin lesion as in this case located on the glans penis, and overlying the sexually transmitted disease gonorrhea. Adapted from CDC

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  This male presented with a purulent penile discharge due to gonorrhea with an overlying penile pyodermal lesion. Pyoderma involves the formation of a purulent skin lesion, in this case located on the glans penis, and overlying the sexually transmitted disease gonorrhea.Adapted from CDC

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  This patient presented with symptoms later diagnosed as due to Gonococcal pharyngitis.Gonococcal pharyngitis is a sexually-transmitted disease acquired through oral sex with an infected partner. The majority of throat infections caused by gonococci have no symptoms, but some can suffer from mild to severe sore throat.Adapted from CDC

• This technician is collecting a specimen from a male suspected of having gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is “stripped” towards the orifice to express some pus. A thin sterile swab is then inserted 23cm into the urethra and rotated before being withdrawn. Adapted from CDC

  This technician is collecting a specimen from a male suspected of having gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is “stripped” towards the orifice to express some pus. A thin sterile swab is then inserted 23cm into the urethra and rotated before being withdrawn. Adapted from CDC

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  This patient presented with a gonorrheal ecthyma on the skin due to systemically disseminated N. gonorrhoeae bacteria. An ecthyma is a cutaneous eruption consisting of a large, round pustule on an inflamed base caused by untreated gonococcal bacteria spread systemically throughout the bloodstream.Adapted from CDC

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  This was a skin lesion on a patient with gonorrhea due to the systemic spread of N. gonorrhoeae bacteria. Gonorrhea is caused by Neisseria gonorrhoeae. If left untreated, will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

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  This was a newborn with gonococcal ophthalmia neonatorum caused by a maternally transmitted gonococcal infection. Unless preventative measures are taken, it is estimated that gonococcal ophthalmia neonatorum will develop in 28% of infants born to women with gonorrhea. It affects the corneal epithelium causing microbial keratitis, ulceration and perforation.Adapted from CDC

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  This patient with diagnosed gonococcal urethritis presented with unilateral gonococcal conjunctivitis. See PHIL 16400, for the appearance of her eye 24 hours following treatment with 4.8 million units of aqueous procaine penicillin G (APPG) and probenicid. If untreated N. gonorrhoeae bacteria may spread to the bloodstream, and thereby, throughout the body. The most common symptoms are then rash and joint pains, but other generalized symptoms may result as well such as conjunctivitis.Adapted from CDC

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  This patient presented with gonorrhea and a disseminated gonococcal skin infection about the ankle. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

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  This is a photograph of a skin lesion on a patient diagnosed with gonorrhea. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

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  This is a skin lesion in a patient with systemically disseminated Neisseria gonorrhoeae bacteria. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such fully systemic dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

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  Here a technician is about to collect an intraurethral specimen to be tested for gonorrhea, or non-specific urethritis. Doctors or other health care workers usually use three laboratory techniques to diagnose gonorrhea: staining samples directly for the bacterium, detection of bacterial genes or DNA in the urine, and growing the bacteria in laboratory cultures.Adapted from CDC

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  This photograph shows the collection of a specimen from a male suspected of having gonorrhea.When collecting a male specimen, if no discharge is evident, the urethra is stripped towards the orifice to express some pus. A thin sterile swab is then inserted 23 cm into the urethra and rotated before being withdrawn.Adapted from CDC

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  The foot of this patient is swollen due to gonococcal arthritis. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

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  Note the gonococcal lesion on the skin of the left arm due to the bacterium Neisseria gonorrhoeae. N. gonorrhoeae, a gram-negative diplococcus, is the causative agent for Gonorrhea. Though these bacteria can infect the genital tract, the mouth, and the rectum, they can become disseminated throughout a person’s bloodstream. Adapted from CDC

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  Close-up of a gonococcal lesion on the skin of a patient’s arm. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions in the form of gray pustules. Adapted from CDC

Genital Herpes

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  Viewed from the right posterior-oblique view, the male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Here you see the patient’s feet from a left lateral perspective revealing papules on the dorsal surface of the left foot. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment. Adapted from CDC

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  Viewed from the right posterior-oblique view, the male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

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  This male patient presented with maculopapular lesions on the distal penile shaft that were first thought to be due to syphilis, but through the process of conducting a differential diagnosis, was later determined to be due to a Herpesviridae infection. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.Adapted from CDC

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  This was a posterior view of the back and buttocks of a male patient, in a clinical setting, who had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

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  The male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. See PHIL 15819, for another view of this patient in the same setting. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

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  This image depicts the right foot of an infant born with a herpes simplex infection, known as neonatal herpes, or herpes simplex neonatorum, which had manifested itself through the development of maculopapular lesions of the foot’s heal and sole. See PHIL 6510, for another view of this condition.Adapted from CDC

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  This image depicts the perineal region of a male patient which displayed a perianal mucocutaneous lesion caused by a herpes simplex infection. Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) or type 2 (HSV-2). Most genital herpes is caused by HSV-2. Most individuals have no or only minimal signs or symptoms from HSV-1 or HSV-2 infection. When signs do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Typically, another outbreak can appear weeks or months after the first, but it almost always is less severe and shorter than the first outbreak. Although the infection can stay in the body indefinitely, the number of outbreaks tends to decrease over a period of years. Adapted from CDC

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  This neonate displayed a maculopapular outbreak on his feet due to congenitally acquired herpes simplex virus. In this instance, due to the age of the patient, this condition is known as herpes simplex neonatorum. See PHIL 15115, for a closer view of these lesions. Genital HSV can cause potentially fatal infections in babies. It is important that women avoid contracting herpes during pregnancy because a first episode during pregnancy causes a greater risk of transmission to the baby. If a woman has active genital herpes at delivery, a cesarean delivery is usually performed. Fortunately, infection of a baby from a woman with herpes infection is rare.Adapted from CDC

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  This 7 year old child with a history of recurrent herpes labialis presented with a periocular herpes simplex vesicular outbreak. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. Adapted from CDC

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  This patient presented with what were recurrent characteristic vesiculopapular herpes simplex lesions on his anterior thigh. These early vesiculopapular herpetic lesions on the anterior thigh (Cntr) had yet to rupture. Herpes simplex virus is a member of a group of viruses including those which cause oral herpes (usually HSV-1), and genital herpes (usually HSV-2). Adapted from CDC

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  This male presented with primary vesiculopapular herpes genitalis lesion at the base of his penis due to the HSV-2 serotype. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.

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  This patient presented with what was diagnosed as a herpes genitalis outbreak on the penile shaft due to HSV-2. Genital herpes is a sexually transmitted disease caused by the herpes simplex viruses type 1 (HSV-1), and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Symptoms typically include one or more blisters on or around the genitals or rectum. Adapted from CDC

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  This patient presented with what was diagnosed as a herpes genitalis outbreak on the penile shaft due to HSV-2. Genital herpes is a sexually transmitted disease caused by the herpes simplex viruses type 1 (HSV-1), and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Symptoms typically include one or more blisters on or around the genitals or rectum. Adapted from CDC

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  This patient presented with what was differentially diagnosed as a herpes genitalis outbreak on the penile glans and shaft. Note that what at first appears as erythematous areas are actually coalescence of herpes genitalis “micro-ulcers”. Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2). Adapted from CDC

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  This male presented with primary vesiculopapular herpes genitalis lesions on his glans penis, and penile shaft. When signs of herpes genitalis do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur.

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  This 7 year old child with history of recurrent herpes labialis presented with a periocular herpes simplex vesicular outbreak. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.Adapted from CDC

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  This male patient presented with a maculopapular herpetic rash on the penile shaft and corona of the glans penis. When signs of genital herpes do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they appear. Adapted from CDC

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  This 7 year old child presented with a generalized herpes simplex vesiculopapular rash over his trunk 5 days after onset. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.

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  This patient presented with a generalized Herpes hominis vesiculopapular rash over the dorsum of the left foot. Herpesvirus hominis, otherwise known as “herpes simplex virus” is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. Adapted from CDC

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  This was an outbreak of herpes genitalis manifested as blistering around the vaginal introitus due to the HSV-2 virus. The sexually transmitted herpes simplex virus type-2 (HSV-2) typically causes one or more blisters to form on, or around the genitals or rectum, which break, leaving tender ulcers that may take 2-4 wks to heal after making their initial appearance.Adapted from CDC

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  Herpes simplex ulcerations on the lateral plantar surface of an infant’s foot. Women who acquire genital herpes during pregnancy can transmit the virus to their babies. Untreated Herpes Simplex Virus (HSV) infections in newborns can result in mental retardation and death.Adapted from CDC

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  Blisters on the vulva due to a recurring Herpes II (HSV-2) virus infection. Symptoms from HSV-1 or HSV-2 infection, when signs do occur, typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Adapted from CDC

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  Blisters on the penis due to a recurring Herpes II (HSV-2) virus infection. Symptoms from HSV-1 or HSV-2 infection, when signs do occur, typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Adapted from CDC

Pubic lice infestation

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  This 2006 image depicted five body lice, Pediculus humanus var. corporis, which from left to right included three nymphal-staged lice, beginning with a stage N1, then N2, and thirdly a N3-staged nymph, followed by an adult male louse, and finally an adult female louse. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus capitis (head louse), Pediculus humanus corporis (body louse, clothes louse) and Phthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

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  This photomicrograph depicts a dorsal view of an adult female human head louse, Pediculus humanus capitis. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus capitis (head louse), Pediculus humanus corporis (body louse, clothes louse) and Pthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations (pediculosis and pthiriasis) are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

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  This illustration depicts a dorsal view of a “crab louse”, Phthirus pubis, a member of the suborder Anoplura, or “sucking lice”. The crab louse Phthirus pubis, is not known to carry disease producing organisms. Infestations usually occur in the pubic region of humans, and may occasionally be found on other coarse body hair, such as hair on the legs, armpits, mustache, beard, eyebrows, or eyelashes. Infestations of young children are usually on the eyebrows or eyelashes. Lice found on the head are not pubic lice; they are head lice. Adapted from CDC

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  This illustration depicts some of the morphologic differences seen in two “sucking lice” of the Order Annoplura. The louse on the left is a “body louse”, Pediculus humanus var. corporis, and the louse on the right is a “crab” or “pubic louse”, Phthirus pubis. Note that both of these lice are wingless, and possess three pairs of claw-tipped legs, which allows them to firmly grasp the hair shafts to which they remain attached as human ectoparasitic pests. Adapted from CDC

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  This photograph reveals the presence of crab lice, Phthirus pubis with reddish-brown crab feces. Pubic lice are generally found in the genital area on pubic hair; but may occasionally be found on other coarse body hair, such as hair on the legs, armpit, mustache, beard, eyebrows, and eyelashes. Adapted from CDC

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  This is an illustration comparing the Head Louse, Pediculus humanus, with the Pubic Louse, Phthirus pubis. These insects use their hook-like appendages to grasp unto the hair shafts of their hosts in body regions unique to its species, i.e. the head louse infests the head region of its host, while the pubic louse infests its host’s pubic region. Adapted from CDC

• 

  This patient presented with an infestation of Phthirus pubis, or crab lice. A Phthirus pubis infestation has caused the erythematous lesions seen in the pubic region of this patient in response to the bites of the crab lice arthropods. Adapted from CDC

• 

  This image depicts a dorsal view of a female head louse, Pediculus humanus var. capitis. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus var. capitis (head louse), Pediculus humanus var. corporis (body louse, clothes louse) and Pthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations (pediculosis and pthiriasis) are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

Scabies

• 

  Under a moderate modification, this photomicrograph revealed the histopathologic changes in a human skin sample from the site of a number of scabies burrows, due to an infestation of Sarcoptes scabiei var. hominis. Note that the scabies had burrowed into the upper layers of this patient’s skin, into the epidermis, superficial to the stratum basale, also known as the stratum germinativum. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

• 

  This image depicts the anterior aspect of a patient’s lower legs, either of which displaying the pathologic consequences of an infestation of Sarcoptes scabiei var. hominis, otherwise known as scabies. Of note, were the secondary severe excoriations, resulting from the patient having scratched at the primary maculopapular rash caused by the scabies bites. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

• 

  This close view of the genitalia of a male patient reveals the presence of erosive, inflamed lesions, which had been caused by an infestation of scabies, Sarcoptes scabiei var. hominis. The lesions are on the penile glans, and the preputial skin. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

• 

  This photograph depicting the dorsal surface of a human hand focused on the interdigital web space between the index and middle fingers, and revealed the presence of papules due to an infestation of the human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

• 

  The right axillary region of this male patient exhibited a papular rash, which had been caused by an infestation of the human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

• 

  This photomicrograph reveals a single human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies, that had burrowed itself into the epidermal layers of a skin tissue sample extracted from an unknown host. The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs. The most common symptoms of scabies are intense itching and a pimple-like skin rash. The scabies mite usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies. Scabies occurs worldwide and affects people of all races and social classes. Scabies can spread rapidly under crowded conditions where close body contact is frequent. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks. Adapted from CDC

• 

  This woman presented with a rash composed of pimple-like irritations on the abdomen and thorax due to canine scabies. If an animal is infested with scabies, or mange, and comes in close contact with humans, the mites can get under the skin causing itching and irritation. However, this form of scabies is mild, and the mites die in a couple of days without reproducing. Adapted from CDC

Syphilis

• Description Adapted from CDC

  Description Adapted from CDC

Trichomoniasis

• 

  This photomicrograph of a wet-mounted vaginal discharge specimen, reveals numbers of Trichomonas vaginalis protozoan parasites, leading to a diagnosis of trichomoniasis, or “trich”, which is a very common sexually transmitted disease (STD) that is caused by infection with T. vaginalis. Although symptoms of the disease vary, most women and men who have the parasite cannot tell they are infected. The parasite is passed from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina, or urethra), and in men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite is usually transmitted from a penis to a vagina, or from a vagina to a penis, but it can also be passed from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not, but it probably depends on factors like the person’s age and overall health. Infected people without symptoms can still pass the infection on to others. Adapted from CDC

• 

  This patient presented with a "strawberry cervix” due to a Trichomonas vaginalis infection, or trichomoniasis. The term “strawberry cervix” is used to describe the appearance of the cervix due to the presence of T. vaginalis protozoa. The cervical mucosa reveals punctate hemorrhages along with accompanying vesicles or papules.

---

Parasite Gallery

A

Acanthocephaliasis

Bolbosoma spp.

• 

  Transverse section through the body wall of Bolbosoma sp. in an intestinal biopsy specimen, stained with H&E. Image taken at 100x magnification. Cetaceans are the normal definitive hosts for Bolbosoma spp., and humans usually become infected after eating under-cooked fish which serve as paratenic hosts for the parasite.
  Adapted from CDC

• 

  Higher-magnification (200x) of the specimen in Figure 1. Identifiable in this image are the characteristic thin cuticle (CU, black arrow), syncytial epidermis (EP), longitudinal muscles (blue arrows) and eggs (green arrows).
  Adapted from CDC

• 

  Transverse section through the body wall of Bolbosoma sp. in an intestinal biopsy specimen, stained with H&E. Image taken at 100x magnification. In this image, a portion of the reproductive system is visible within the pseudocoelom.
  Adapted from CDC

Moniliformis moniliformis

Eggs of M. moniliformis

• 

  Eggs of M. moniliformis liberated from an adult worm that was recovered from the stool of a patient.
  Adapted from CDC

• 

  Egg of M. moniliformis liberated from an adult worm that was recovered from the stool of a patient.
  Adapted from CDC

Adults of M. moniliformis

• 

  Adult of M. moniliformis.
  Adapted from CDC

• 

  Adult of M. moniliformis.
  Adapted from CDC

• 

  Higher magnification of the anterior end of the specimen in Figures 1 and 2, showing a close-up of the proboscis.
  Adapted from CDC

• 

  Higher magnification of the anterior end of the specimen in Figures 1 and 2, showing a close-up of the proboscis.
  Adapted from CDC

Macracanthorhynchus hirudinaceous

Eggs of M. hirudinaceous

• 

  Eggs of M. hirudinaceous in an unstained wet mount of stool.
  Adapted from CDC

• 

  Egg of M. hirudinaceous in an unstained wet mount of stool.
  Adapted from CDC

• 

  Image of the same egg in Figure 2, but in a different plane of focus, showing the textured exterior.
  Adapted from CDC

Adults of M. hirudinaceous

• 

  Adult of M. hirudinaceous.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 1, showing a close-up of the anterior end and the proboscis containing hooks.
  Adapted from CDC

• 

  Cross-section of the intestine of a pig, stained with H&E, showing the anterior end of an adult Macracanthorhynchus hirudinaceous embedded within the intestinal wall.
  Adapted from CDC

African trypanosomiasis (Sleeping sickness)

Trypansoma brucei

Trypansoma brucei ssp. in thick blood smear stained with Giemsa

• 

  Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
  Adapted from CDC

• 

  Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
  Adapted from CDC

• 

  Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
  Adapted from CDC

Trypansoma brucei ssp. in thin blood smear stained with Giemsa

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
  Adapted from CDC

Trypansoma brucei ssp. in thin blood smears stained with Wright-Giemsa

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
  Adapted from CDC

Trypansoma brucei ssp. in thin blood smear, beginning to divide

• 

  Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa. The trypomastigote is beginning to divide; dividing forms are seen in African trypanosomes, but not in American trypanosomes.
  Adapted from CDC

Amebiasis

Amebiasis cysts

• 

  Cyst of E. histolytica/E. dispar stained with trichrome. Note the chromatoid body with blunt ends (red arrow).

Amebiasis trophozioites

• 

  Trophozoites of E. histolytic with ingested erythrocytes stained with trichrome. The ingested erythrocytes appear as dark inclusions. The parasite above show nuclei that have the typical small, centrally located karyosome, and thin, uniform peripheral chromatin.
  Adapted from CDC

• 

  Entamoeba histolytica trophozoites in colon tissue stained with H&E.
  Adapted from CDC

American trypanosomiasis (Chagas disease)

Trypanosoma cruzi

Trypanosoma cruzi in thick blood smears stained with Giemsa

• 

  Trypanosoma cruzi in thick blood smears stained with Giemsa.
  Adapted from CDC

T. cruzi in thin blood smears stained with Giemsa

• 

  T. cruzi trypomastigote in a thin blood smear stained with Giemsa. Note the typical C-shape of the trypomastigote that characterizes T. cruzi in fixed blood smears.
  Adapted from CDC

• 

  T. cruzi trypomastigote in a thin blood smear stained with Giemsa.
  Adapted from CDC

• 

  T. cruzi trypomastigote in a thin blood smear stained with Giemsa.
  Adapted from CDC

• 

  Higher magnification of Figure 3, T. cruzi.
  Adapted from CDC

T. cruzi in cerebrospinal fluid (CSF) stained with Giemsa

• 

  Trypanosoma cruzi trypomastigote in cerebrospinal fluid (CSF) stained with Giemsa.
  Adapted from CDC
  

T. cruzi amastigotes in heart tissue

• 

  Trypanosoma cruzi amastigotes in heart tissue. The section is stained with hematoxylin and eosin (H&E).
  Adapted from CDC
  

• 

  Trypanosoma cruzi amastigotes in heart tissue. The section is stained with H&E.
  Adapted from CDC
  

T. cruzi epimastigotes, from culture

• 

  Trypanosoma cruzi epimastigotes from culture. Note the location of the kinetoplast anterior to the nucleus.
  Adapted from CDC
  

Ancylostomiasis (Hookworm)

Ancylostoma caninum

• 

  Anterior end of an adult of Ancylostoma caninum, a dog parasite that has been found to produce a rare human infection known as eosinophilic enteritis.
  Adapted from CDC

Ancylostoma duodenale

• 

  Adult worm of Ancylostoma duodenal. Anterior end is depicted showing cutting teeth.
  Adapted from CDC

Necator americanus

• 

  Adult worm of Necator americanus. Anterior end showing mouth parts with cutting plates.
  Adapted from CDC

Angiostrongyliasis

Angiostrongylus cantonensis

• 

  Angiostrongylus cantonensis third stage (L3), infective larva recovered from a slug. Image captured under differential interference contrast (DIC) microscopy.
  Adapted from CDC

• 

  A. cantonensis (L3), infective larvae recovered from a slug. Image captured under DIC microscopy.
  Adapted from CDC

• 

  Higher magnification of Image 2. Note the terminal projection on the tip of the tail which is characteristic of A. cantonensis.
  Adapted from CDC

• 

  Angiostrongylus cantonensis third stage (L3), infective larva, in a wet mount, recovered from a slug. Note the terminal projection on the tip of the tail which is characteristic of A. cantonensis.
  Adapted from CDC

• 

  A. cantonensis L3, infective larvae, in wet mounts, recovered from slugs.
  Adapted from CDC

• 

  A. cantonensis L3, infective larvae, in wet mounts, recovered from slugs.
  Adapted from CDC

Angiostrongylus costaricensis

A. costaricensis Eggs

• 

  Angiostrongylus costaricensis eggs in intestinal tissue stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Thin-shelled A. costaricensis eggs in intestinal tissue stained with H&E, a feature consistent with the presence of mature female worms.
  Adapted from CDC

• 

  A. costaricensis first stage (L1) larva in intestinal tissue stained with H&E
  Adapted from CDC

A. costaricensis adult female in tissue sections stained with H&E

• 

  Angiostrongylus costaricensis female worm in appendix tissue sections stained with hematoxylin and eosin (H&E). Image courtesy of Regions Hospital, St. Paul, MN.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 1. Notice the thick, multinucleate intestine (IN) and eggs (EG) within the uterus (UT).
  Adapted from CDC

• 

  Another image from the specimen seen in Figure 1.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 3. Shown here are the thick, multinucleate intestine (IN), reproductive tubes (RT), and lateral chords (LC).
  Adapted from CDC

Anisakiasis

Anisakis simplex

• 

  Cross-section of Anisakis sp., viewed under DIC microscopy.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 1. Note the tall, prominent muscle cells (MU) and Y-shaped lateral chords (LC), characteristic for this genus.
  Adapted from CDC

Pseudoterranova decipiens

Pseudoterranova sp. larval worms

• 

  Anterior ends of Pseudoterranova sp. worms; images taken at 40x and 200x magnification, respectively.
  Adapted from CDC

• 

  Anterior ends of Pseudoterranova sp. worms; images taken at 40x and 200x magnification, respectively.
  Adapted from CDC

• 

  Anterior end of Pseudoterranova sp. The red arrow indicates the intestinal cecum.
  Adapted from CDC

• 

  Close-up of the intestinal cecum in the same specimen seen in Figure 3.
  Adapted from CDC

• 

  Mid-section of a Pseudoterranova sp. worm, showing the esophagus and intestine. Image taken at 40x magnification.
  Adapted from CDC

• 

  Posterior end of Pseudoterranova sp. Image taken at 200x magnification.
  Adapted from CDC

Cross sections of Pseudoterranova sp. worms Cross sections of anisakid worms.

• 

  Cross-section of Pseudoterranova sp. Note the large butterfly-shaped lateral chords (black arrows), characteristic for this genus.
  Adapted from CDC

• 

  Cross-section of Pseudoterranova sp. viewed under differential interference contrast (DIC) microscopy.
  Adapted from CDC

Ascariasis

Ascaris lumbricoides

Adult A. lumbricoides

• 

  Adult female A. lumbricoides.
  Adapted from CDC

Unfertilized egg of A. lumbricoides

• 

  Unfertilized egg of A. lumbricoides in an unstained wet mount, 200x magnification.
  Adapted from CDC

Fertilized egg of A. lumbricoides

• 

  Fertilized egg of A. lumbricoides in unstained wet mounts of stool, with embryos in the early stage of development.
  Adapted from CDC

A. lumbricoides in tissue specimen

• 

  Eggs of A. lumbricoides in an appendix biopsy, stained with H&E. This image was taken at 200x magnification.
  Adapted from CDC

B

Babesiosis

Babesia microti

• 

  Babesia microti in a thin blood smear stained with Giemsa. Babesia sp. cannot be identified to the species level by morphology alone; additional testing, such as PCR, is always recommended.
  Adapted from CDC

• 

  Babesia microti in a thin blood smear stained with Giemsa. Babesia sp. cannot be identified to the species level by morphology alone; additional testing, such as PCR, is always recommended. Note the tetrad form in this image.
  Adapted from CDC

• 

  Babesia microti in a thin blood smear stained with Giemsa. Note the intra-erythrocytic vacuolated forms indicated by the black arrows.
  Adapted from CDC

Balantidiasis

Balantidium coli

B. coli cysts

• 

  B. coli cysts in a wet mount, unstained.
  Adapted from CDC

B. coli trophozoites

• 

  B. coli trophozoite in a wet mount, 500× magnification. Note the visible cilia on the cell surface.
  Adapted from CDC

• 

  Balantidium coli trophozoites in colon tissue stained with hematoxylin and eosin (H&E) at 400x magnification.
  Adapted from CDC

Baylisascariasis

Baylisascaris procyonis

Baylisascaris procyonis eggs

• 

  Unembryonated egg of B. procyonis.
  Adapted from CDC

• 

  Embryonated eggs of B. procyonis, showing the developing larva inside.
  Adapted from CDC

Baylisascaris procyonis larvae

• 

  Larva of B. procyonis hatching from an egg.
  Adapted from CDC

• 

  Cross-sections of larvae of B. columnaris in muscle of a laboratory-infected mouse. The larval morphology and microscopic manifestations would be similar with B. procyonis in human tissue. Image taken at 400x magnification.
  Adapted from CDC

Baylisascaris procyonis larvae

• 

  Larva of B. procyonis hatching from an egg.
  Adapted from CDC

• 

  Cross-sections of larvae of B. columnaris in muscle of a laboratory-infected mouse. The larval morphology and microscopic manifestations would be similar with B. procyonis in human tissue. Image taken at 400x magnification.
  Adapted from CDC

Bed Bugs

Cimex lectularius

• 

  Two adults and one nymph (arrow) of C. lectularius, collected in a hotel in urban Georgia.
  Adapted from CDC

• 

  Close-up of one of the adults in Figure 1.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 2. Note the reduced forewings (arrow).
  Adapted from CDC

• 

  Ventral view of the specimen in Figure 2.
  Adapted from CDC

• 

  Higher magnification of the specimen in Figure 4, showing a close-up of the typical hemipteran piercing-sucking mouthparts (arrow).
  Adapted from CDC

• 

  Nymph of C. lectularius. The blue marks represent 1 mm.
  Adapted from CDC

Bertiella infection

• 

  Eggs of Bertiella sp. liberated from proglottids. The proglottids were shed from a human patient who had lived for a number of years in Africa. In several of these eggs, the pyriform apparatus can be easily seen. Images courtesy of Clinipath Pathology, Perth, Australia.
  Adapted from CDC

• 

  An egg of Bertiella sp. liberated from a gravid proglottid. The arrows point to the hooklets.
  Adapted from CDC

• 

  Proglottids of Bertiella sp.
  Adapted from CDC

Bertiella struderi

• 

  Scolex of Bertiella studeri. Image courtesy of Richard Bradbury.
  Adapted from CDC

Blastocystis hominis infection

Blastocystis hominis

Blastocystis hominis cyst-like forms in wet mounts

• 

  B. hominis cyst-like forms in a wet mount, unstained.
  Adapted from CDC

• 

  B. hominis cyst-like form in a wet mount, unstained.
  Adapted from CDC

B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy

• 

  B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy.
  Adapted from CDC

• 

  B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy.
  Adapted from CDC

B. hominis cyst-like forms in wet mounts stained with iodine

• 

  B. hominis cyst-like forms in wet mounts stained in iodine.
  Adapted from CDC

• 

  B. hominis cyst-like forms in wet mounts stained in iodine.
  Adapted from CDC

B. hominis cyst-like forms stained with trichrome

• 

  B. hominis cyst-like forms stained with trichrome. The nuclei in the peripheral cytoplasmic rim are visible, staining purple.
  Adapted from CDC

• 

  B. hominis cyst-like forms stained with trichrome. The nuclei in the peripheral cytoplasmic rim are visible, staining purple.
  Adapted from CDC

• 

  Blastocystis hominis cyst-like forms stained with trichrome.
  Adapted from CDC

• 

  Blastocystis hominis cyst-like forms stained with trichrome.
  Adapted from CDC

• 

  B. hominis cyst-like forms stained with trichrome.
  Adapted from CDC

• 

  B. hominis cyst-like forms undergoing binary fission; stained with trichrome.
  Adapted from CDC

• 

  B. hominis cyst-like forms stained with trichrome.
  Adapted from CDC

C

Cercarial dermatitis (Swimmer’s itch)

Austrobilharzia variglandis

Cercaria of Austrobilharzia variglandis

• 

  Cercaria of Austrobilharzia variglandis, which can cause cercarial dermatitis.
  Adapted from CDC

• 

  Cercaria of Austrobilharzia variglandis, which can cause cercarial dermatitis. Note the forked 'tail' and a pair of 'eye spots' near the anterior end.
  Adapted from CDC

Clinical manifestations of Austrobilharzia variglandis

• 

  Skin of a patient showing the inflammatory response to cercaria in the skin.
  Adapted from CDC

Chilomastix mesnili

Chilomastix mesnili trophozoites, trichrome stain

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

Chilomastix mesnili cysts, trichrome stain

• 

  Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst (lower) and trophozoite (upper) of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
  Adapted from CDC

Chilomastix mesnili cysts in wet mounts

• 

  Cyst of C. mesnili in a concentrated wet mount of stool, stained with iodine. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Cyst of C. mesnili in a concentrated wet mount of stool, stained with iodine. Image taken at 1000x magnification.
  Adapted from CDC

Clonorchiasis

Clonorchis sinensis

Clonorchis sinensis eggs

• 

  C. sinensis egg: the small knob at the abopercular end is visible in this image.
  Adapted from CDC

• 

  C. sinensis egg. Note the operculum resting on "shoulders;" image taken at 400× magnification.
  Adapted from CDC

• 

  C. sinensis egg; images taken at 400× magnification.
  Adapted from CDC

• 

  C. sinensis egg; images taken at 400× magnification.
  Adapted from CDC

Clonorchis sinensis adults

• 

  Adult of C. sinensis.
  Adapted from CDC

• 

  Adult of C. sinensis stained with carmine. Clearly visible in this image are the oral sucker (OS), pharynx (PH), ceca (CE), acetabulum, or ventral sucker (AC), uterus (UT), vitellaria (VT) and testes (TE).
  Adapted from CDC

Clonorchis sinensis eggs

• 

  Shells of Parafossarulus manchouricus, the most common snail host of C. sinensis in endemic areas in southeast Asia. Image courtesy of the Web Atlas of Medical Parasitology and the Korean Society for Parasitology.
  Adapted from CDC

• 

  Bithynia sp., another common intermediate host of C. sinensis. Image courtesy of Michal Manas.
  Adapted from CDC

Coenurosis

Taenia spp.

Gross coenurus specimens

• 

  Large, polycephalic coenurus removed from the shoulder of a baboon (Papio sp.).
  Adapted from CDC

• 

  Close-up of a coenurus of T. multiceps removed from the eye of a patient, broken open to show multiple protoscoleces.
  Adapted from CDC

Coenuri in tissue specimens, stained with hematoxylin and eosin (H&E)

• 

  Coenurus removed from a subcutaneous nodule in the shoulder area of a patient, stained with hematoxylin and eosin (H&E). Image taken at 50x magnification. Although the species was not identified in this case, the pathology is consistent with T. serialis.
  Adapted from CDC

• 

  Higher magnification (200x) of the coenurus in Figure 1.
  Adapted from CDC

• 

  Higher magnification (200x) of the same specimen shown in Figures 1 and 2. The black arrows point to hooklets in the protoscoleces.
  Adapted from CDC

• 

  Higher magnification (200x) of the same specimen shown in Figures 1 and 2. The black arrows point to hooklets in the protoscoleces.
  Adapted from CDC

Coenurus in an eye specimens, stained with hematoxylin and eosin (H&E)

• 

  Cross-section of a human eye, showing multiple protoscoleces within a coenurus.
  Adapted from CDC

• 

  Higher magnification (200x) of the coenurus in Figure 1.
  Adapted from CDC

• 

  Higher magnification (200x) of protoscoleces shown in Figures 1 and 2.
  Adapted from CDC

• 

  Higher magnification (200x) of protoscoleces shown in Figures 1 and 2.
  Adapted from CDC

• 

  Higher magnification of the protoscolex in Figure 4, showing multiple hooklets.
  Adapted from CDC

Cryptosporidiosis

Cryptosporidium spp.

Cryptosporidium sp. oocysts in a wet mount

• 

  Cryptosporidium spp. oocysts (pink arrows) in wet mount. A budding yeast (brown arrow) is in the same field.
  Adapted from CDC

• 

  Cryptosporidium parvumoocysts in wet mount, under differential interference contrast (DIC) microscopy. The oocysts are rounded and measure 4.2 µm - 5.4 µm in diameter. Sporozoites are visible inside the oocysts, indicating that sporulation has occurred.
  Adapted from CDC

Cryptosporidium sp. oocysts stained with trichrome

• 

  Cryptosporidium sp. oocysts stained with trichrome. Oocysts may be detected, but should not be confirmed by this method. Trichrome staining is inadequate for a definite diagnosis because oocysts will appear unstained. Here the Cryptosporidium oocysts are represented by red arrows; the blue arrow represents yeast.
  Adapted from CDC

• 

  Cryptosporidium sp. oocyst stained with trichrome. Oocysts may be detected, but should not be confirmed by this method. Trichrome staining is inadequate for a definite diagnosis because oocysts will appear unstained. Here the Cryptosporidium oocyst is represented by a red arrow; the blue arrows represent yeast.
  Adapted from CDC

Cryptosporidium sp. oocysts stained with modified acid-fast

• 

  Cryptosporidium parvum oocysts stained with modified acid-fast. Against a blue-green background, the oocysts stand out in a bright red stain. Sporozoites are visible inside the two oocysts to the right in this image.
  Adapted from CDC

• 

  Cryptosporidium parvum oocysts stained with modified acid-fast. Against a blue-green background, the oocysts stand out in a bright red stain.
  Adapted from CDC

• 

  Cryptosporidium sp. oocysts stained with modified acid-fast.
  Adapted from CDC

• 

  Cryptosporidium sp. oocyst stained with modified acid-fast.
  Adapted from CDC

Cryptosporidium sp. oocysts unstained on a slide stained with modified acid-fast

• 

  Cryptosporidium sp. oocysts (red arrows) that did not take up the modified acid-fast stain. The slide was counterstained with methylene blue. Note that yeast cells did stain red (yellow arrows).
  Adapted from CDC

• 

  Unstained Cryptosporidium sp. oocysts (black arrows) on a slide stained with modified acid-fast. The slide was counterstained with malachite green.
  Adapted from CDC

Cryptosporidium sp. oocysts stained with safranin

• 

  Cryptosporidium sp. oocysts stained with safranin.
  Adapted from CDC

• 

  Cryptosporidium sp. oocysts stained with safranin.
  Adapted from CDC

Cryptosporidium sp. oocysts stained with Ziehl-Neelsen modified acid-fast

• 

  Cryptosporidium sp. oocysts stained with Ziehl-Neelson modified acid-fast. Image contributed by the Oregon State Public Health Laboratory.
  Adapted from CDC

Cryptosporidium parvum oocysts stained with the fluorescent stain auramine-rhodamine

• 

  Cryptosporidium parvum oocysts stained with the fluorescent stain auramine-rhodamine.
  Adapted from CDC

Oocysts of C. parvum' and cysts of Giardia duodenalis labeled with immunofluorescent antibodies

• 

  Cryptosporidium sp. oocysts labeled with immunofluorescent antibodies. Images contributed by the Kansas Department of Health and Environment.
  Adapted from CDC

• 

  Cryptosporidium sp. oocyst labeled with immunofluorescent antibodies. Images contributed by the Kansas Department of Health and Environment.
  Adapted from CDC

• 

  Cryptosporidium sp. oocysts (yellow arrows) and cysts of Giardia duodenalis (red arrow) labeled with immunofluorescent antibodies.
  Adapted from CDC

• 

  Cryptosporidium sp. oocysts (yellow arrows) and cysts of Giardia duodenalis (red arrows) labeled with immunofluorescent antibodies.
  Adapted from CDC

Cyclosporiasis

Cyclospora cayetanensis

Cyclospora cayetanensis oocysts in wet mounts

• 

  Oocyst of C. cayetanensis in an unstained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis in an unstained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis in an unstained wet mount of stool. Image taken at 1000x magnification.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis in an unstained wet mount of stool. Image taken at 1000x magnification.
  Adapted from CDC

Cyclospora cayetanensis oocysts stained with trichrome

• 

  Oocyst of C. cayetanensis stained with trichrome; while the oocyst is visible, the staining characteristics are inadequate for a reliable diagnosis.
  Adapted from CDC

• 

  Oocysts of C. cayetanensis stained with trichrome; while the oocyst is visible, the staining characteristics are inadequate for a reliable diagnosis.
  Adapted from CDC

C. cayetanensis oocysts viewed under ultraviolet (UV) microscopy

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under UV microscopy.
  Adapted from CDC

C. cayetanensis oocysts stained with modified acid-fast

• 

  Oocysts of C. cayetanensis stained with modified acid-fast stain. Note the variability of staining in the four oocysts.
  Adapted from CDC

• 

  Two oocysts of C. cayetanensis stained with modified acid-fast stain. Both oocysts failed to take up the carbol fuschin stain. Image courtesy of the Arizona State Public Health Laboratory.
  Adapted from CDC

• 

  Oocysts of C. cayetanensis stained with modified acid-fast stain. Note the wrinkled edge and the lack of stain in the two oocysts. Image courtesy of the Arizona State Public Health Laboratory.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis stained with modified acid-fast stain.
  Adapted from CDC

• 

  Oocysts of C. cayetanensis stained with modified acid-fast stain.
  Adapted from CDC

• 

  Oocysts of C. cayetanensis stained with modified acid-fast stain.
  Adapted from CDC

C. cayetanensis oocysts stained with safranin (SAF)

• 

  Oocyst of C. cayetanensis stained with safranin (SAF).
  Adapted from CDC

• 

  Oocyst of C. cayetanensis stained with safranin (SAF).
  Adapted from CDC

• 

  Oocyst of C. cayetanensis stained with safranin (SAF).
  Adapted from CDC

• 

  Oocyst of C. cayetanensis stained with safranin (SAF).
  Adapted from CDC

• 

  A pair of oocysts of C. cayetanensis stained with safranin (SAF).
  Adapted from CDC

• 

  Oocyst of C. cayetanensis (yellow arrow) along with an oocyst of Cryptosporidium parvum (red arrow), stained with safranin (SAF). Cryptosporidium spp. also stain with the safranin and modified acid-fast stains.
  Adapted from CDC

C. cayetanensis oocysts viewed under differential interference contrast (DIC) microscopy

• 

  Oocyst of C. cayetanensis viewed under differential interference contrast (DIC) microscopy. The refractile globules are easily visible under DIC.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under differential interference contrast (DIC) microscopy. The refractile globules are easily visible under DIC.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under DIC microscopy. There are two sporocysts are visible in this image.
  Adapted from CDC

• 

  Oocyst of C. cayetanensis viewed under DIC microscopy.
  Adapted from CDC

• 

  A pair of oocysts of C. cayetanensis viewed under DIC microscopy.
  Adapted from CDC

• 

  Rupturing oocyst of C. cayetanensis viewed under DIC microscopy. One sporocyst has has been released from the mature oocyst; the second sporocyst is still contained within the oocyst wall.
  Adapted from CDC

Cysticercosis

Taenia solium

Larval Taenia solium

• 

  Larval Taenia solium cyst in a section of a lesion found in the right frontal lobe of a patient stained with hematoxylin and eosin (H&E), magnification 40×.
  Adapted from CDC

• 

  An entire cysticercus seen within the bladder walls (blue arrows). A single scolex is visible inside yellow circle) within the cyst.
  Adapted from CDC

• 

  Higher magnification (100×) of the cyst in Figures 1 and 2. The parenchymatous portion of the cysticercus can be better observed.
  Adapted from CDC

• 

  The extensive folding of the spiral canal and one sucker of the scolex (black arrow) are apparent. Calcareous corpuscles can be seen in the fibrous tissues (green arrows).
  Adapted from CDC

• 

  Cross-sections of cysticerci stained with H&E, at 40x magnification
  Adapted from CDC

• 

  Cross-sections of cysticerci stained with H&E, at 100x magnification.
  Adapted from CDC

Cystoisosporiasis (Isosporiasis)

Cystoisospora belli (Isospora belli)

Cystoisospora belli oocysts

• 

  Immature oocyst of C. belli in an unstained wet mount, containing a single sporoblast.
  Adapted from CDC

• 

  Immature oocyst of C. belli stained with safranin, containing a single sporoblast.
  Adapted from CDC

• 

  Immature oocyst of C. belli stained with acid-fast, showing a single sporoblast.
  Adapted from CDC

• 

  Oocyst of C. belli viewed under ultraviolet (UV) microscopy, showing two sporoblasts.
  Adapted from CDC

• 

  Immature oocyst of C. belli in an unstained wet mount showing a single sporoblast.
  Adapted from CDC

• 

  Immature oocyst of C. belli in an unstained wet mount showing two sporoblasts.
  Adapted from CDC

• 

  Same oocyst as in Figure 1 but viewed under differential interference contrast (DIC)
  Adapted from CDC

• 

  Same oocyst as in Figure 2 but viewed under ultraviolet (UV) fluorescent micrscopy.
  Adapted from CDC

• 

  Same oocyst as in Figures 1 and 3 but viewed under ultraviolet (UV) fluorescent micrscopy.
  Adapted from CDC

• 

  Same oocyst as in Figures 2 and 4 but viewed under UV microscopy.
  Adapted from CDC

Cystoisospora belli oocysts, stained with hematoxylin and eoisin (H&E)

• 

  Oocyst of C. belli in the epithelial cells of a mammalian host, stained with H&E (yellow arrow).
  Adapted from CDC

• 

  Oocyst of C. belli in the epithelial cells of a mammalian host, stained with H&E (yellow arrow).
  Adapted from CDC

D

Dicrocoeliasis

Dicrocoelium dendriticum

Dicrocoelium dendriticum eggs in wet mounts

• 

  Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
  Adapted from CDC

• 

  Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
  Adapted from CDC

• 

  Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
  Adapted from CDC

• 

  Egg of D. dendriticum in an unstained wet mount of stool.
  Adapted from CDC

• 

  Egg of D. dendriticum in an unstained wet mount of stool.
  Adapted from CDC

Dicrocoelium dendriticum adults

• 

  Adult of D. dendriticum, stained with carmine. Structures illustrated in this figure include: oral sucker (OS), acetabulum (AC), uterus (UT), testes (TE), and vitelline glands (VT).
  Adapted from CDC

Intermediate hosts of Dicrocoelium dendriticum

• 

  Zebrina detrita, a common first intermediate host for D. dendriticum. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Formica fusca, a common second intermediate host for D. dendriticum in Europe. Image courtesy of Sedeer El-Showk.
  Adapted from CDC

Dientamoeba fragilis infection

Dientamoeba fragilis

Dientamoeba fragilis binucleate trophozoites stained with trichrome

• 

  Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate form of trophozoites of D. fragilis, stained with trichrome. A cyst-like form of Blastocystis hominis lies to the left of the D. fragilis.
  Adapted from CDC

Dientamoeba fragilis uninucleate trophozoites stained with trichrome

• 

  Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
  Adapted from CDC

• 

  Binucleate and uninucleate forms of trophozoites of D. fragilis, stained with trichrome.
  Adapted from CDC

Dioctophymiasis

Dioctophyme renale

Larvae of Dioctotphyme renale in human tissue

• 

  Cross-sections of larvae of D. renal in a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Images courtesy of the Laboratory of Parasitology, National Public Health Research Center in Vilnius, Lithuania.
  Adapted from CDC

• 

  Cross-sections of larvae of D. renal in a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Images courtesy of the Laboratory of Parasitology, National Public Health Research Center in Vilnius, Lithuania
  Adapted from CDC

• 

  Higher-magnification of the specimens shown in Figures 1 and 2, showing a close-up of the characteristic intestine, with cuboidal, uninucleate cells, pigment, and microvilli.
  Adapted from CDC

• 

  Higher-magnification of the specimens shown in Figures 1 and 2, showing a close-up of the characteristic intestine, with cuboidal, uninucleate cells, pigment, and microvilli.
  Adapted from CDC

• 

  Higher-magnification of the specimens shown in Figures 1-4. Shown in this image are the tall, polymyarian muscle cells, the characteristic ventral chord with a U-shaped row of nuclei (black arrow), and three pseudocoelomic membranes (red arrows).
  Adapted from CDC

• 

  Close-up of Figure 1, showing the ventral chord (black-arrow).
  Adapted from CDC

Eggs of D. renale in animal tissue

• 

  Egg of D. renale in the kidney of a mink, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Egg of D. renale in the kidney of a mink, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

Diphyllobothriasis

Diphyllobothrium latum

Diphyllobothrium latum eggs in wet mounts

• 

  Eggs of D. latum in an iodine-stained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
  Adapted from CDC

• 

  Note the knob at the abopercular end. Image courtesy of the Oregon State Public Health Laboratory.
  Adapted from CDC

• 

  Eggs of D. latum within a proglottid. Image courtesy of the Florida State Public Health Laboratory.
  Adapted from CDC

• 

  Eggs of D. latum within a proglottid.
  Adapted from CDC

• 

  Eggs of D. latum in an unstained wet mount.
  Adapted from CDC

• 

  Eggs of D. latum in an unstained wet mount of stool. Note the opercula are open.
  Adapted from CDC

Eggs of Diphyllobothrium latum eggs in wet mounts

• 

  Egg of D. latum in an unstained wet-mount of stool.
  Adapted from CDC

Proglottids of Diphyllobothrium latum

• 

  Section of an adult D. latum containing many proglottids. The scolex was not present in this specimen. Image courtesy of the Florida State Public Health Laboratory.
  Adapted from CDC

• 

  Close-up of a few of the proglottids from the specimen in Figure 1, showing the rosette-shaped uterus at the center of each proglottid.
  Adapted from CDC

• 

  Carmine-stained proglottids of D. latum, showing the rosette-shaped ovaries.
  Adapted from CDC

• 

  Carmine-stained proglottids of D. latum, showing the rosette-shaped ovaries.
  Adapted from CDC

• 

  Scolex of D. latum.
  Adapted from CDC

Dipylidium caninum infection

Dipylidium caninum egg packets in wet mounts

• 

  D. caninum egg packet, containing 8 visible eggs, in a wet mount.
  Adapted from CDC

• 

  D. caninum egg packet in a wet mount.
  Adapted from CDC

• 

  D. caninum egg packet in wet mount.
  Adapted from CDC

• 

  D. caninum egg packet in wet mount.
  Adapted from CDC

• 

  D. caninum egg packet in wet mount.
  Adapted from CDC

D. caninum eggs in wet mounts under conventional and differential interference contrast microscopy

• 

  D. caninum eggs clumped together in a wet mount. Image taken at 200x magnification.
  Adapted from CDC

• 

  D. caninum eggs clumped together in a wet mount. Image taken at 400x magnification, hooklets in the some of the eggs are visible.
  Adapted from CDC

• 

  D. caninum eggs clumped together under differential interference contrast microscopy (same eggs as in Figure 2).
  Adapted from CDC

• 

  Close up of Figure 3. Note the visible hooklets in three of the eggs.
  Adapted from CDC

D. caninum proglottids

• 

  D. caninum proglottid under a dissecting microscope cleared with lactophenol.
  Adapted from CDC

• 

  D. caninum proglottid.
  Adapted from CDC

• 

  D. caninum proglottid partially cleared with lactophenol, showing eggs and egg packets.
  Adapted from CDC

• 

  D. caninum proglottid. The genital pores are clearly visible in the carmine-stained proglottid.
  Adapted from CDC

Cross-section of a D. caninum proglottid stained with hematoxylin and eosin (H&E)

• 

  Cross-section of a D. caninum proglottid stained with H&E. Image taken at 100x magnification.
  Adapted from CDC

• 

  Cross-section of a D. caninum proglottid stained with H&E. Image taken at 200x magnfication.
  Adapted from CDC

• 

  Cross-section of a D. caninum proglottid stained with H&E. Image taken at 400x magnification
  Adapted from CDC

• 

  Cross-section of a D. caninum proglottid stained with H&E. Image taken at 1000x magnification.
  Adapted from CDC

D. caninum scolex

• 

  D. caninum scolex.
  Adapted from CDC

Adult tapeworm of D. caninum

• 

  Adult tapeworm of D. caninum. The scolex of the worm is very narrow and the proglottids, as they mature, get larger.
  Adapted from CDC

Dirofilariasis

Dirofilaria sp.

• 

  Cross-section of Dirofilaria sp. from a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Morphologic features visible in this image include tall, prominent muscle cells (MU), coiled vagina (VG), coiled intestine (IN), lateral chords (LC), and prominent internal lateral ridges (IR). Image courtesy of Drs. Dirk Elston and Paul Bourbeau.
  Adapted from CDC

• 

  Cross-sections of Dirofilaria spp. from a subcutaneous scalp nodule, stained with H&E. Image courtesy of the Department of Dermatopathology, University of Michigan, Ann Arbor, MI.
  Adapted from CDC

• 

  Cross-sections of Dirofilaria sp. from a subcutaneous nodule above the right breast of a female patient who traveled to several western European countries, stained with H&E. Image taken at 100x magnification. Image courtesy of Dr. Truus Derks.
  Adapted from CDC

• 

  Higher magnification of the same specimen as Figure 3, taken at 400x magnification. Note the presence of lateral chords (blue arrows) and internal lateral ridge (black arrow).
  Adapted from CDC

• 

  Dirofilaria sp. (suspect D. tennis) removed from the eye of a patient.
  Adapted from CDC

• 

  Close-up of the specimen in Figure 5 showing the cuticular ridging. A uterine tube can also be seen through the cuticle.
  Adapted from CDC

Dracunculiasis (Guinea Worm Disease)

Drancunculus medinensis

A female Dracuncunculus medinensis in a human host

• 

  The female Guinea worm induces a painful blister.
  Adapted from CDC

• 

  After rupture of the blister, the worm emerges as a whitish filament in the center of a painful ulcer which is often secondarily infected. (Images contributed by Global 2000/The Carter Center, Atlanta, Georgia).
  Adapted from CDC

E

Echinococcosis (Hydatid disease)

Echinococcus granulosus

Echinococcus granulosus in tissue

• 

  Protoscoleces in a hydatid cyst removed from lung tissue, stained with hematoxylin and eosin (H&E). Image taken at 200x magnification. Image courtesy of Phoenix Children's Hospital, Phoenix, AZ.
  Adapted from CDC

• 

  Higher magnification (600x) of the protoscoleces in Figure 1.
  Adapted from CDC

• 

  Cross-section of an E. granulosus cyst, stained with H&E. The cyst wall is composed of an acellular laminated external layer (green arrow) and a thin, germinal (nucleated) inner layer (yellow arrow). Note the brood capsule (black arrow) with protoscoleces (blue arrows) inside. Image taken at 40x magnification.
  Adapted from CDC

• 

  Higher magnification (200x) of the cyst in Figure 3, showing daughter cyst (brood capsule). Note the hooklets (purple arrow) inside one of the protoscoleces and the calcareous corpuscles (light blue arrows) along the germinal layer.
  Adapted from CDC

• 

  Protoscoleces liberated from a hydatid cyst.
  Adapted from CDC

• 

  Protoscoleces liberated from a hydatid cyst.
  Adapted from CDC

Echinococcus granulosus adults

• 

  Echinococcus granulosus adult, stained with carmine.
  Adapted from CDC

• 

  Close-up of the scolex of E. granulosus in Figure 1. In this focal plane, one of the suckers is clearly visible, as is the ring of rostellar hooks.
  Adapted from CDC

Echinococcus multilocularis

• 

  Echinococcus multilocularis in liver tissue, stained with hematoxylin and eosin (H&E). Magnification at 200x
  Adapted from CDC

• 

  Higher magnification (400x) of the specimen in Figure 1. Notice a pair of refractile hooks (yellow arrows). Cestode hooks do not stain with H&E but may be visible with proper adjustment of the microscope.
  Adapted from CDC

• 

  Echinococcus multilocularis in tissue, stained with H&E. Magnification at 200x.
  Adapted from CDC

• 

  Higher magnification (400x) of the specimen in Figure 3. Notice the refractile hook (green arrow).
  Adapted from CDC

Echinostomiasis

Echinostoma spp.

Echinostoma spp. egg in wet mounts

• 

  Egg of Echinostoma sp. in an unstained wet mount of stool. Image taken at 400x magnification.
  Adapted from CDC

Echinostoma spp. adults

• 

  Adult of E. revolutum, stained with carmine. Structures illustrated in this figure include: oral sucker (OS), armed collar (CL), cirrus sac (CS), ventral sucker, or acetabulum (AC), uterus containing eggs (UT), ovary (OV), paired testes (TE), and vitelline glands (VT). This species has been recorded from humans in Taiwan.
  Adapted from CDC

Echinostoma sp. in tissue, stained with hematoxylin and eosin (H&E)

• 

  Adult Echinostoma removed during a colonoscopy, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Higher magnification of the anterior end of the specimen in Figure 1. Notice the acetabulum (ventral sucker, AC).
  Adapted from CDC

• 

  Higher magnification of the posterior end of the specimen in Figure 1. Notice the vitelline glands (VT) and lobed testes (TE).
  Adapted from CDC

• 

  Higher magnification of the specimen in Figures 1-3. Shown here are eggs (EG) within the size range forEchinostoma spp. (roughly 100 micrometers in length, taking into account they are sections and may not be cut in a perfect horizontal plane).
  Adapted from CDC

Intermediate hosts of Echinostoma spp.

• 

  Lymnaea sp. This snail genus has been recorded as a second intermediate host for E. malayanum. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Radix sp. This snail genus has been recorded as a first intermediate host for E. hortense and a second intermediate host for E. cinetorchis. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Gyraulus sp. This snail genus has been recorded as an intermediate host for E. cinetorchis. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Viviparus sp. This snail genus has been recorded as a second intermediate host for E. cinetorchis and E. hortense. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Corbicula sp. This bivalve genus has been recorded as a second intermediate host for E. lindoense. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

Enterobiasis (Pinworm Infection)

Enterobius vermicularis

Enterobius vermicularis eggs

• 

  Eggs of E. vermicularis in a cellulose-tape preparation.
  Adapted from CDC

• 

  Eggs of E. vermicularis in a wet mount.
  Adapted from CDC

• 

  Egg of E. vermicularis in an iodine-stained wet mount from a formalin concentrate. Image contributed by the Kansas State Public Health Laboratory.
  Adapted from CDC

• 

  Egg of E. vermicularis teased from an adult worm recovered from a colonoscopy. Image contributed by the South Carolina Department of Health and Environmental Control, Bureau of Laboratories.
  Adapted from CDC

• 

  Eggs of E. vermicularis viewed under UV microscopy.
  Adapted from CDC

• 

  Eggs of E. vermicularis viewed under UV microscopy.
  Adapted from CDC

Enterobius vermicularis adult worms

• 

  Adult male of E. vermicularis from a formalin-ethyl acetate (FEA) concentrated stool smear. The worm measured 1.4 mm in length. Image contributed by the Centre for Tropical Medicine and Imported Infectious Diseases, Bergen, Norway.
  Adapted from CDC

• 

  Close-up of the anterior end of the worm in Figure 1. The esophagus, divided into muscular and bulbous portions and separated by a short, narrow isthmus, is visible in the image, as are the cephalic expansions.
  Adapted from CDC

• 

  Close-up of the posterior end of the worm in Figure 1. Note the blunt end. The spicule is withdrawn into the worm in this specimen.
  Adapted from CDC

• 

  Anterior end of an adult female of E. vermicularis, recovered from a colonscopy. Image contributed by the South Carolina Department of Health and Environmental Control, Bureau of Laboratories.
  Adapted from CDC

• 

  Posterior end of the worm in Figure 4. Note the long, slender pointed tail.
  Adapted from CDC

Enterobius vermicularis in tissue, stained with hematoxylin and eosin (H&E)

• 

  Cross-section of a male E. vermicularis from tissue, stained with H&E. Notice the presence of the alae (blue arrow), intestine (red arrow) and testis (black arrow).
  Adapted from CDC

• 

  Cross-section of an adult female E. vermicularis from the same specimen shown in Figure 1. Note the presence of the alae (blue arrow), intestine (green arrow) and ovaries (black arrows).
  Adapted from CDC

• 

  Cross section of an adult female E. vermicularis stained with H&E, recovered during a colonoscopy. Note the prominent alae (blue arrow) and the presence of eggs (yellow arrow). Image contributed by Sheboygan Memorial Hospital, Wisconsin.
  Adapted from CDC

• 

  Longitudinal section of an adult female E. vermicularis from the same specimen as Figure 3. Note the presence of many eggs.
  Adapted from CDC

• 

  Egg of E. vermicularis in a colon biopsy specimen, stained with H&E.
  Adapted from CDC

• 

  Egg of E. vermicularis in a colon biopsy specimen, stained with H&E.
  Adapted from CDC

Enteromonas hominis

Enteromonas hominis cysts

• 

  Cyst of E. hominis, possessing four nuclei, in a stool specimen stained with iron-hematoxylin.
  Adapted from CDC

• 

  Cyst of E. hominis, possessing four nuclei, in a stool specimen stained with iron-hematoxylin.
  Adapted from CDC

F

Fascioliasis

Fasciola hepatica

Fasciola hepatica eggs

• 

  Egg of F. hepatica in an unstained wet mount, taken at 400x magnification.
  Adapted from CDC

• 

  Egg of F. hepatica in an unstained wet mount, taken at 400x magnification.
  Adapted from CDC

• 

  Egg of F. hepatica in an unstained wet mount.
  Adapted from CDC

F. hepatica adults

• 

  Unstained adult of F. hepatica fixed in formalin.
  Adapted from CDC

• 

  Adult of F. hepatica stained with carmine.
  Adapted from CDC

F. hepatica adults observed in endoscopic retrograde cholangiopancreatography (ERCP)

• 

  Unstained adult of F. hepatica fixed in formalin.
  Adapted from CDC

• 

  Adult of F. hepatica stained with carmine.
  Adapted from CDC

Intermediate hosts of Fasciola spp.

• 

  Galba truncately, the main intermediate host of F. hepatica throughout most of the fluke's natural range in Europe and western Asia. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Galba humilis, a host of F. hepatica in Canada and parts of the United States. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Fossaria bulamoides, a host for F. hepatica in the western United States. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Pseudosuccinea columella, a lymnaeid snail that has been introduced into South America and serves as an intermediate host for F. hepatica in Venezuela and Colombia. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

Fasciolopsiasis

Fasciolopsis buski

Fasciolopsis buski eggs

• 

  Egg of F. buski in a unstained wet mount.
  Adapted from CDC

• 

  Egg of F. buski in a unstained wet mount.
  Adapted from CDC

• 

  Egg of F. buski in unstained wet mounts.
  Adapted from CDC

• 

  Egg of F. buski in an unstained wet mount of stool.
  Adapted from CDC

• Higher magnification (400x) of the egg in Figure 4. Adapted from CDC

  Higher magnification (400x) of the egg in Figure 4.
  Adapted from CDC

Fasciolopsis buski adults

• 

  Adult fluke of F. buski. Image contributed by Georgia Division of Public Health.
  Adapted from CDC

• 

  Adult fluke of F. buski.
  Adapted from CDC

Intermediate hosts of F. buski

• 

  Snail in the genus Hippeutis, an intermediate host for F. buski. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

• 

  Snail in the genus Segmentina, an intermediate host for F. buski. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
  Adapted from CDC

Fleas

Ctenocephalides canis

• 

  The dog flea, C. canid. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
  Adapted from CDC

Ctenocephalides felis

• 

  The cat flea, C. felis. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
  Adapted from CDC

• 

  The cat flea, C. felis. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
  Adapted from CDC

Free-living amebic infections

Acanthamoeba

Acanthamoeba spp. cysts

• 

  Cysts of Acanthamoeba spp. in culture.
  Adapted from CDC

• 

  Cysts of Acanthamoeba spp. in culture.
  Adapted from CDC

• 

  Cyst of Acanthamoeba sp. from brain tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Cyst of Acanthamoeba sp. from brain tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Cysts of Acanthamoeba sp. (green arrows) in tissue, stained with H&E.
  Adapted from CDC

Acanthamoeba spp. trophozoites

• 

  Trophozoite of Acanthamoeba sp. from culture. Notice the slender, spine-like acanthapodia.
  Adapted from CDC

• 

  Trophozoites of Acanthamoeba sp. from culture. Notice the slender, spine-like acanthapodia.
  Adapted from CDC

• 

  Trophozoite of Acanthamoeba sp. in tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Trophozoites of Acanthamoeba sp. in a corneal scraping, stained with H&E.
  Adapted from CDC

Balamuthia mandrillaris

Balamuthia mandrillaris cysts

• 

  Cysts of B. mandrillaris.
  Adapted from CDC

• 

  Close-up of one of the cysts in Figure 1.
  Adapted from CDC

• 

  Cyst of B. mandrillaris.
  Adapted from CDC

• 

  Cyst of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Cyst of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of the University of Kentucky Hospital, Lexington, Kentucky.
  Adapted from CDC

• 

  Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of the University of Kentucky Hospital, Lexington, Kentucky.
  Adapted from CDC

• 

  Cysts of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of Cook Children’s Hospital, Fort Worth, Texas.
  Adapted from CDC

• 

  Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of Cook Children’s Hospital, Fort Worth, Texas.
  Adapted from CDC

Balamuthia mandrillaris trophozoites

• 

  Trophozoite of B. mandrillaris in culture.
  Adapted from CDC

• 

  Trophozoite of B. mandrillaris in culture.
  Adapted from CDC

• 

  Trophozoite of B. mandrillaris in culture.
  Adapted from CDC

• 

  Trophozoite of B. mandrillaris in culture.
  Adapted from CDC

• 

  Several trophozoites of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  A single trophozoite (green arrow) of B. mandrillaris in brain tissue, stained with H&E.
  Adapted from CDC

• 

  A single trophozoite (black arrow) of B. mandrillaris in brain tissue, stained with H&E.
  Adapted from CDC

Naegleria fowleri

Naegleria fowleri cysts

• 

  Cyst of N. fowleri in culture.
  Adapted from CDC

Naegleria fowleri trophozoites

• 

  Trophozoite of N. fowleri in culture.
  Adapted from CDC

• 

  Trophozoites of N. fowleri in culture.
  Adapted from CDC

• 

  Ameboflagellate trophozoite of N. fowleri.
  Adapted from CDC

• 

  Trophozoite of N. fowleri in CSF, stained with hematoxylin and eosin (H&E).
  Adapted from CDC

• 

  Trophozoite of N. fowleri in CSF, stained with trichrome. Image courtesy of the Texas State Health Department.
  Adapted from CDC

Sappinia pedata

• 

  Four trophozoites (yellow arrows) of S. pedata in brain tissue, stained with hematoxylin and eosin (H&E). In three of the amebae, the two nuclei can easily be seen.
  Adapted from CDC

G

Giardiasis

Giardia duodenalis (syn. G. lamblia, G. intestinalis)

Giardia duodenalis cysts in wet mounts stained with iodine

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis cyst in a wet mount stained with iodine.
  Adapted from CDC

Giardia duodenalis cysts in wet mounts under differential interference contrast (DIC) microscopy

• 

  G. duodenalis cyst in a wet mount under differential interference contrast (DIC) microscopy. Image taken at 1000× magnification.
  Adapted from CDC

• 

  Two G. duodenalis cysts in a wet mount under DIC microscopy; image taken at 1000× magnification.
  Adapted from CDC

G. duodenalis cysts in trichrome stain

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
  Adapted from CDC

• 

  G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
  Adapted from CDC

G. duodenalis trophozoites in wet mounts

• 

  G. duodenalis trophozoite in a wet mount stained with iodine.
  Adapted from CDC

• 

  G. duodenalis trophozoite in a wet mount under differential interference contrast (DIC) microscopy. Image taken at 1000× magnification.
  Adapted from CDC

G. duodenalis trophozoites stained with trichrome

• 

  G. duodenalis trophozoite stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis trophozoite stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis trophozoite stained with trichrome.
  Adapted from CDC

• 

  G. duodenalis trophozoites. Image contributed by the Vermont Department of Health Laboratory.
  Adapted from CDC

G. duodenalis trophozoites in unique stains

• 

  G. duodenalis trophozoites in Kohn stain.
  Adapted from CDC

• 

  G. duodenalis trophozoites in a Giemsa stained mucosal imprint.
  Adapted from CDC

Cysts of Giardia duodenalis and oocysts of Cryptosporidium parvum

• 

  Cysts of G. duodenalis (lower right) and oocysts of Cryptosporidium parvum (upper left) labeled with commercially available immunofluorescent antibodies.
  Adapted from CDC

Gnathostomiasis

Gnathostoma spinigerum

Head bulb and cuticular spines of Gnathostoma spinigerum

• 

  Head bulb.
  Adapted from CDC

• 

  Cuticular spines of the posterior body part.
  Adapted from CDC

Detail of cuticular spines of the anterior body part of G. spinigerum

• 

  Detail of cuticular spines of the anterior body part.
  Adapted from CDC

Detail of nondendiculated cuticular spines of G. spinigerum

• 

  Detail of nondendiculated cuticular spines.
  Adapted from CDC

• 

  Detail of nondendiculated cuticular spines.
  Adapted from CDC