Reinfection with Schistosoma haematobium following school-based chemotherapy with praziquantel in four highly endemic villages in Cote d'Ivoire

We present the comparative evaluation of school-based chemotherapy with pra ziquantel on Schistosoma haematobium reinfection patterns, 6, 12, 18 and 24 months after systematic treatment of schoolchildren in four villages of so uth-central Cote d'Ivoire. At baseline, very high S. haematobium infection prevalences of 88-94% were found in Taabo Village, located adjacent to a la rge man-made lake, and in Batera and Bodo, where small dams were constructe d. In Assinze, a village with no man-made environmental alterations, the ba seline infection prevalence was significantly lower (67%). The parasitologi cal cure rate, assessed 4 weeks after praziquantel administration in the vi llage with the highest prevalence and intensity of infection, was high (82% ), and showed a clear association with infection intensity prior to treatme nt. Six months after chemotherapy, significant reductions in the prevalence and intensity of infection were observed in all villages. However, infecti on prevalence was again high in Taabo Village (63%) and in Batera (49%). Di fferent patterns of reinfection occurred in the four villages: rapid reinfe ction in Taabo Village to reach almost baseline infection prevalence 12 mon ths post-treatment; slow but gradual increase in the prevalence and intensi ty of infection in Bodo; marked increase in prevalence and intensity of inf ection during the second year of the follow-up in Assinz; and prevalence an d intensity of infection that remained almost constant between 6 and 24 mon ths post-treatment in Batera. Our study confirms that S. haematobium reinfe ction patterns largely depend on the local epidemiological setting, which i s of central importance to tailoring treatment strategies that are well ada pted to these different settings.