Parasitic diseases. Other roundworms. Trichuris, hookworm, and Strongyloides

Trichuriasis may be asymptomatic or, in heavy infection, lead to profuse, bloody diarrhea and rectal prolapse. Diagnosis is made by finding the distinctive barrel shaped eggs in the stool or in the heavily infested patient, by anoscopy and identification of worms attached to reddened and ulcerated rectal mucosa. Mebendazole is the drug of choice in treatment. Capillariasis, a parasitic infection encountered mainly in the Philippine Islands, is of interest in that the eggs may be confused with the eggs of trichuris. Hookworm disease is generally asymptomatic, but in heavy infection, leads to iron deficiency and hypochromic, microcytic anemia. Diagnosis is made by finding the characteristic hookworm eggs on a examination of a direct fecal film. Accidental invasion of humans by dog and cat hookworm leads to cutaneous larva migrans, also known as "creeping eruption." Human hookworm is treated most effectively with mebendazole, while the rash produced by creeping eruption responds to topical thiabendazole. Strongyloides is fairly common in rural areas of the southeastern United States and may be seen in the urban setting among inmates of mental institutions, prisons, and in immigrants who formerly resided in endemic tropical regions. Because of its remarkable capacity for dissemination of larvae throughout the body, this parasite is now recognized as a serious problem for the patient who is immunocompromised. Diagnosis is made by finding larvae in the stool or by the Enterotest. All infected patients should be treated with thiabendazole. I consider the issue on Drugs For Parasitic Infections, published annually or biannually by The Medical Letter on Drugs and Therapeutics, to be the single best source of information on the treatment of parasitic diseases for primary care physicians.