(See also Approach to Parasitic Infections Approach to Parasitic Infections Human parasites are organisms that live on or in a person and derive nutrients from that person (its host). There are 3 types of parasites: Single-cell organisms (protozoa, microsporidia) Multicellular... read more .)
Trichuriasis is the 3rd most common soil-transmitted roundworm infection. An estimated 604 to 795 million people are infected worldwide. Trichuris trichiura occurs principally in developing tropical or subtropical areas where human feces is used as fertilizer or where people defecate indiscriminately onto soil. Children are the most heavily infected. In the United States, most cases of trichuriasis are in immigrants or travelers returning from endemic areas with poor sanitation and hygiene, but there are locally acquired cases in some southern areas.
Infection is spread via the fecal-oral route. Ingested eggs hatch and enter the crypts of the small bowel as larvae. After maturing for 1 to 3 months, the worms migrate to the cecum and ascending colon, where they attach to the superficial epithelium, mate, and lay eggs.
Adult worms are estimated to live 1 to 2 years, although some may live longer.
Symptoms and Signs of Trichuriasis
Light Trichuris infections are often asymptomatic.
Patients with heavy infections may have abdominal pain, anorexia, and diarrhea; weight loss, anemia, and rectal prolapse may result, particularly in children.
Diagnosis of Trichuriasis
Microscopic examination of stool
Diagnosis of trichuriasis is made by microscopic examination of stool; the characteristic lemon-shaped eggs with clear opercula at both ends are readily apparent. When anoscopy, proctoscopy, or colonoscopy is done for other indications, wiggling adult worms may be seen protruding into the bowel lumen.
Complete blood count (CBC) is done to check for anemia.
Treatment of Trichuriasis
Mebendazole 100 mg orally twice a day for 3 days is effective for patients with trichuriasis. A single dose of mebendazole 500 mg has been used in mass treatment programs. Also effective for individual patients is albendazole 400 mg orally once a day for 3 days or ivermectin 200 mcg/kg orally once a day for 3 days. These drugs should usually not be used during pregnancy.
If treatment with ivermectin is planned, patients should be assessed for coinfection with Loa loa Loiasis Loiasis is a filarial nematode infection with Loa loa. Symptoms include localized angioedema (Calabar swellings) in skin and subconjunctival migration of adult worms. Diagnosis is by detecting... read more if they have been in areas of central Africa where it is transmitted; ivermectin can induce severe reactions in patients with high levels of Loa loa microfilariae.
Prevention of trichuriasis is possible through effective sewage disposal systems, sanitary food preparation, avoidance of potentially contaminated water, and good personal hygiene including handwashing.
Trichuriasis occurs principally in developing tropical or subtropical areas where human feces is used as fertilizer or where people defecate onto soil, but infections also occur in the southern United States, mainly in children.
Infection is spread via the fecal-oral route.
Light infections are often asymptomatic; heavy infections may cause abdominal pain, anorexia, diarrhea, and, in children, weight loss, anemia, and rectal prolapse.
To diagnose trichuriasis, examine a stool sample for the characteristic lemon-shaped eggs with clear opercula at both ends.
Treat with mebendazole, albendazole, or ivermectin.
If treatment with ivermectin is planned, assess patients for coinfection with Loa loa if they have been in areas of central Africa where it is transmitted; ivermectin can induce severe reactions in patients with high levels of Loa loa microfilariae.