Heterogeneities in anti-schistosome humoral responses following chemotherapy.

Schistosomiasis is a major public health problem in Africa, the Middle East, Asia and South America. The main control strategy is to treat infected people with anthelmintic drugs, principally the safe and relatively cheap drug praziquantel. Several treatment re-infection studies in humans have shown that praziquantel can have long-term effects beyond a transient reduction of infection intensity. These long-term effects include the altering of schistosome-specific immune responses in humans, which is associated with resistance to re-infection. Differences have been observed in treatment-induced immunological changes between individuals and between populations. This article discusses the contributions of host- and parasite-related heterogeneities to post-treatment humoral responses in humans infected with Schistosoma mansoni and Schistosoma haematobium and considers the practical implications of such heterogeneity for schistosome immuno-epidemiology studies.