This modification of the life cycle, called internal autoinfection, explains persistent strongyloidiasis, as long as 40 years in patients who have moved to areas where the disease is not generally found. Autoinfection may produce heavy infections and severe disease, especially in patients with reduced immunity such as those receiving corticosteroids or other immunosuppressive drug treatment. Many Strongyloides infections are mild and go unnoticed. Moderate infections may cause a burning pain in the abdomen. Nausea and vomiting may be present, and diarrhea and constipation alternate.
Severe infections result in anemia, weight loss, and chronic diarrhea.
Laboratory diagnosis includes the examination of feces and duodenal contents for larvae. Scientists at the National Institute of Allergy and Infectious Diseases have developed a reliable blood test to detect antibodies to Strongyloides. Ivermectin given in one or two days, or albendazole given in two courses 10 days apart also are effective. Trichinosis Trichinosis is an infection by the larvae of a most versatile roundworm, Trichinella spiralis. This parasite can infect virtually every meat-eating mammal.