Treatment of strongyloidiasis with thiabendazole: an analysis of toxicity and effectiveness.

The effects of therapy with thiabendazole were investigated in 43 men who had been infected with Strongyloides stercoralis for 35 years. Side effects of drug treatment were frequent and sometimes severe; nausea was the most common symptom. Six months later, approximately one third of patients had persistent diarrhoea, recurrent urticaria or considered that their general health had not improved. Parasites were found in 7% of persons six months after treatment. Blood eosinophil counts fell dramatically but the falls in serum IgE levels and serum Strongyloides antibody titres were less marked. Assessment of response to treatment is difficult because of the insensitivity of parasitological techniques and the ability of this parasite to replicate. It is concluded that thiabendazole cannot always be relied upon to eradicate infection.