The diagnosis of strongyloidiasis with special reference to the value of the filarial complement fixation test as a screening test

In 72 patients from Africa, Asia, America and Australasia with strongyloidiasis the diagnosis rested in the main on stool concentration techniques, without which light or moderate infection is likely to be missed. Infections may persist for at least 20 years. Eosinophilia was inconstant, but the filarial complement fixation test was poskive in 75%. Successful treatment with thiabendazole caused the test to fall in titre or to revert to negative. Follow up stool examinations confirmed the widespread reports of the efficiency of thiabendazole in this infection. It is important to diagnose this condition. Apart from symptoms directly due to the parasite, the long term use of steroids may lead to superinfection and death, and there is a probable though rare association between strongyloidiasis and septicaemic states dependent on the auto-infective cycle. The filarial complement fixation test may be valuable in pointing to the diagnosis of light to moderate infections; positive tests in the absence of any evidence of filariasis should lead to a careful search for the larvae of Strongyloides stercoralis in the stool, and failing that in the duodenal aspirate.