Anaplasmosis: Difference between revisions
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}} </ref> Anaplasmosis, caused by ''Anaplasma phagocytophilum'', causes symptoms of fever, headache, and [[myalgia]], with [[Gastrointestinal tract|GI]] symptoms occurring in less than half of the patients and a macular, maculopapular of patechial skin rash in less than 10% of patients. Patients who are immunocompromised and on immunosuppressive drugs like corticosteroids and chemotherapeutic medications have severe illness. | }} </ref> Anaplasmosis, caused by ''Anaplasma phagocytophilum'', causes symptoms of fever, headache, and [[myalgia]], with [[Gastrointestinal tract|GI]] symptoms occurring in less than half of the patients and a macular, maculopapular of patechial skin rash in less than 10% of patients. Patients who are immunocompromised and on immunosuppressive drugs like corticosteroids and chemotherapeutic medications have severe illness. | ||
Lab findings: It is characterized by [[thrombocytopenia]], [[leukopenia]], and elevated [[Blood plasma|serum]] [[transaminase]] and [[LDH]] levels in the majority of infected patients, also, anemia and increased serum creatinine can be seen. The causative bacterium is transmitted to humans via ticks.<ref>Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. ''Medical Microbiology, Fifth Edition''. United States: Elsevier Mosby, 2005</ref> | |||
Diagnosis: The decision to start treatment depends on the history of a tick bite, and sign and symptoms of HGA in patients living in endemic areas along with lab features of thrombocytopenia, leukopenia. However, to obtain a definitive diagnosis serological tests such as [[ELISA]], [[PCR]], and examination of peripheral blood for the characteristic intracytoplasmic morulae can be done. | |||
===Lifecycle=== | ===Lifecycle=== | ||
Revision as of 04:00, 20 May 2020
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Faizan Sheraz, M.D. [2]
- This article is about the ruminant disease. For anaplasmosis in dogs, see Ehrlichiosis (canine). For anaplasmosis in humans, see Human granulocytic ehrlichiosis.
Human Granulocytic Anaplasmosis(HGA) is a disease caused by a rickettsial parasite of ruminants, Anaplasma spp. The organism occurs in the erythrocytes and is transmitted by natural means through by a number of haematophagous species of ticks most commonaly by black-legged deer tick Ixodes scapularis and flies. It can also be transmitted iatrogenically by the use of surgical, dehorning, castration, and tattoo instruments and hypodermic needles that are not disinfected between uses. HGA is a notifiable disease in the USA. [1] The annual incidence of HGA in the USA is 6.3 cases per million population from 2008 to 2012.[2] In the United States, anaplasmosis is notably present in the south and west where the tick hosts Dermacentor spp. are found. Although vaccines have been developed, none are currently available in the United States. Early in the 20th century, this disease was considered one of the major economic consequences in the western United States. In the 1980s and 1990s, control of ticks through new acaricides and practical treatment with prolonged-action antibiotics, notably tetracycline, has led to the point where the disease is no longer considered a major problem.
Clinical features
The average incubation period of HGA is 5.5 days after a tick bite.[3] Anaplasmosis, caused by Anaplasma phagocytophilum, causes symptoms of fever, headache, and myalgia, with GI symptoms occurring in less than half of the patients and a macular, maculopapular of patechial skin rash in less than 10% of patients. Patients who are immunocompromised and on immunosuppressive drugs like corticosteroids and chemotherapeutic medications have severe illness.
Lab findings: It is characterized by thrombocytopenia, leukopenia, and elevated serum transaminase and LDH levels in the majority of infected patients, also, anemia and increased serum creatinine can be seen. The causative bacterium is transmitted to humans via ticks.[4]
Diagnosis: The decision to start treatment depends on the history of a tick bite, and sign and symptoms of HGA in patients living in endemic areas along with lab features of thrombocytopenia, leukopenia. However, to obtain a definitive diagnosis serological tests such as ELISA, PCR, and examination of peripheral blood for the characteristic intracytoplasmic morulae can be done.
Lifecycle
The organism can go through a complete lifecycle in the gut of certain species of ticks but the flies appear to be only a mechanical vector, thus, not as important in the maintaining the disease in any given area. The disease causes severe anemia and wasting in adult cattle which are infected. Young cattle and most other ruminants will not show clinical signs if infected but may serve as carriers. Since the organism "hides" from the body's immune system in red blood cells, it is difficult if not impossible for an infection to be totally cleared. As the immune response wanes, the organism again builds up and the host relapses.
Antimicrobial regimen
- Human granulocytic anaplasmosis, suspected or symptomatic [5]
- Preferred regimen: Doxycycline 100 mg PO bid (or IV for those patients unable to take oral medication) for 10 days
- Alternative regimen: Rifampin 300 mg PO bid for 7–10 days (For patients with mild illness due to HGA who are not optimally suited for doxycycline treatment because of a history of drug allergy, pregnancy, or age <8 years)
- Pediatric regimen:
- Children ≥ 8 years of age
- Preferred regimen: Doxycycline 4 mg/kg/day PO bid (Maximum, 100 mg/dose) (or IV for children unable to take an oral medication) for 10 days
- Children < 8 years of age
- Preferred regimen: Rifampin 10 mg/kg bid (Maximum, 300 mg/dose) for 4-5 days
- Note (1): If the patient has concomitant Lyme disease, then Amoxicillin 50 mg/kg/day in 3 divided doses (maximum of 500 mg per dose) OR Cefuroxime axetil 30 mg/kg per day in 2 divided doses (maximum of 500 mg per dose) should be initiated at the conclusion of the course of Doxycycline to complete a 14-day total course of antibiotic therapy
- Note (2): Rifampin is not effective therapy for Lyme disease, patients coinfected with B. burgdorferi should also be treated with Amoxicillin OR Cefuroxime axetil
References
- ↑ Khatri, Akshay; Lloji, Amanda; Doobay, Richard; Wang, Guiqing; Knoll, Bettina; Dhand, Abhay; Nog, Rajat (2019). "Anaplasma phagocytophilum
presenting with orchitis in a renal transplant recipient". Transplant Infectious Disease. 21 (4). doi:10.1111/tid.13129. ISSN 1398-2273. line feed character in
|title=at position 26 (help) - ↑ F. Scott Dahlgren, Kristen Nichols Heitman, Naomi A. Drexler, Robert F. Massung & Casey Barton Behravesh (2015). "Human granulocytic anaplasmosis in the United States from 2008 to 2012: a summary of national surveillance data". The American journal of tropical medicine and hygiene. 93 (1): 66–72. doi:10.4269/ajtmh.15-0122. PMID 25870428. Unknown parameter
|month=ignored (help) - ↑ ME Aguero-Rosenfeld, HW Horowitz, GP Wormser, DF McKenna, J. Nowakowski, J. Munoz & JS Dumler (1996). "Human granulocytic ehrlichiosis: a case series from a medical center in New York State". Annals of internal medicine. 125 (11): 904–908. doi:10.7326 / 0003-4819-125-11-199612010-00006 Check
|doi=value (help). PMID 8967671. Unknown parameter|month=ignored (help) - ↑ Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. Medical Microbiology, Fifth Edition. United States: Elsevier Mosby, 2005
- ↑ Wormser GP, Dattwyler RJ, Shapiro ED, Halperin JJ, Steere AC, Klempner MS; et al. (2006). "The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America". Clin Infect Dis. 43 (9): 1089–134. doi:10.1086/508667. PMID 17029130.