Whipworm infection overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aravind Kuchkuntla, M.B.B.S[2]
Overview
Trichuris trichiura is the third most common nematode worldwide, following Ascaris and Enterobius infections. Infection is acquired by the ingestion of embryonated eggs from contaminated drinking water and food. Whipworm causes disease by colonic mucosal invasion by the adult worm, resulting in inflammation of the colonic mucosa. In most cases, whipworm infection causes no clinical symptoms, but a severe infection can cause abdominal pain, diarrhea, constipation, weight loss, and anemia. The diagnosis of whip worm infection is confirmed by a stool examination for ova and parasites, which may demonstrate the presence of whipworm eggs. Whip worm eggs are barrel-like with two polar plugs. Medical therapy with antihelminthic medications is the primary modality of treatment, using albendazole, mebendazole, and ivermectin. Primary prevention measures include maintaining proper hygiene, hand washing, encouraging people not to defecate outdoors, and improving sewage disposal systems.
Historical Perspective
In 1761, Roederer described whipworm for the first time. In 1771, Carl Linnaeus coined the binomial name for human whipworm as Trichuris trichiura. The human whipworm (Trichuris trichiura) is generally considered "heirloom," since it is found in African non-human primates, and parasite eggs were found in fossilized human feces in archaeological sites before animal domestication and before the Columbian colonization. The origin of human Trichuris is believed to be in Africa, where the parasite was transmitted to humans through early primates.
Classification
Trichuriasis infection is classified by the World Health Organization (WHO) for helminth control programs based on the number of eggs per gram of feces into light, moderate, and heavy infection.
Pathophysiology
Infection is acquired by the ingestion of embryonated eggs from contaminated drinking water and food. The eggs, once ingested, hatch in the small intestine, and the larvae enter the intestinal crypts. The larve migrate to the proximal colon and mature into adult worms. The females begin to oviposit 60 to 70 days after infection and shed between 3,000 and 20,000 eggs per day. Whipworm causes disease by colonic mucosal invasion of the adult worms, resulting in inflammation of the colonic mucosa.
Causes
The human whipworm (Trichuris trichiura or Trichocephalus trichiuris) is a round worm that causes trichuriasis. It is commonly known as the whipworm which refers to the shape of the worm; it looks like a whip with wider "handles" at the posterior end.
Differentiating whipworm infection from other diseases
Trichuris trichiura must be differentiated from other nematode infections, such as ascariasis, hook worm infection, and Strongyloides stercoralis, that can present with diarrhea and abdominal pain.
Epidemiology and Demographics
Trichuris trichiura is the third most common nematode worldwide following Ascaris and Enterobius; in total, the three infections affect approximately 1 billion people. Whip worm infection is endemic in tropical and subtropical countries. The prevalence of Trichuris trichiura is high, affecting 95% of children in countries where protein energy malnutrition and anemias are prevalent.
Risk Factors
Risk factors predisposing patients to the development of whip worm infection include low socio-economic status, low levels of education, poor sanitation, and poor hygiene.
Screening
There is insufficient evidence to recommend routine screening for Whipworm infection.
Natural History, Complications and Prognosis
In most cases, whipworm infection causes no clinical symptoms. A heavy whipworm infection (greater than 10,000 eggs per gram of feces) infection can cause abdominal pain, diarrhea, constipation, weight loss, and anemia. If left untreated, severe infection can result in Trichuris dysentery syndrome. Complications of heavy whipworm infection include chronic dysentry, rectal prolapse, and growth retardation. Prognosis is excellent with antihelminthic treatment and complete recovery occurs in 1 to 2 weeks.
Diagnosis
History and Symptoms
The majority of patients with light trichuriasis infection are asymptomatic. Trichuriasis presents with weight loss, bloody diarrhea, abdominal pain, tenesmus, and rectal prolapse in patients with moderate to heavy infection.
Physical Examination
There are no specific physical examination findings associated with whip worm infection. Patients with severe infection may present with pallor, finger nail clubbing, rectal prolapse, and abdominal tenderness.
Laboratory Findings
The diagnosis of whip worm infection is confirmed by a stool examination for ova and parasites. It will demonstrate the presence of whipworm eggs. There are no specific laboratory findings associated with whip worm infection. Chronic blood loss may demonstrate an iron deficiency anemia on peripheral blood smear with microcytic and hypochromic anemia.
EKG
There are no specific EKG findings associated with whipworm infection.
Chest X-Ray
There are no specific chest X-Ray findings associated with whipworm infection.
CT Scan
CT scan findings are non specific in patients with whipworm infection, but irregular nodular colonic thickening of the cecum and the ascending colon may be present.
Other Imaging Findings
A double contrast barium enema will demonstrate the presence of multiple tiny target-like or pinwheel shaped collections of barium, associated with s-shaped filling defects and appearance characteristic of a male worm with a coiled tip.
Other Diagnostic Findings
The other diagnostic studies for whip worm infection include stool examination for ova and parasites, colonoscopy, and an abdominal ultrasound. Whip worm eggs are barrel-like with two polar plugs. Colonoscopy is not routinely indicated, but it can be performed in patients with non specific symptoms and a negative stool test for the presence of eggs.
Treatment
Medical Therapy
Medical therapy with antihelminthic medications is the primary modality of treatment. The treatment options include albendazole, mebendazole, and ivermectin.
Surgery
Surgery is not recommended for the treatment of whipworm infection.
Prevention
Primary Prevention
Primary prevention measures include maintaining proper hygiene, hand washing, encouraging people not to defecate outdoors, and improving sewage disposal systems.
Secondary Prevention
Secondary preventive measures for whip worm infection are similar to the primary preventive measures.