[Specifics of the epidemiology of urinary schistosomiasis in Mauritius]

Early observations on this disease were made in Mauritius by Chapotin (1812) before the discovery of Schistosoma haematobium. Bulinus cernicus, the snail intermediate host, one of the nine species within the B. forskali group, is restricted to the island and the disease is not occurring in the neighbouring islands of La Reunion and Rodrigues. Under laboratory conditions, the snail susceptibility to the Mauritian strain of S. haematobium has been demonstrated. But the infection rate of the snail remains very low and the transmission of the disease is sporadic except in three foci. Its occurrence is not linked with agriculture or irrigation but is closely related to other man/water contacts in the rivers. Without clinical significant signs, the disease, quite different of the historic description, is largely underestimate. The snail is well adapted to the climatic conditions on Mauritius with a remarkably resistance to long drought periods. In fact, distribution of snail and evolution of population size fluctuate dramatically. Canalization and drainage of rivers, streams and marches since the beginning of malaria outbreak, widespread use of pesticides during the antimalaria spraying campaigns, only overhead irrigation, permanent maintenance of the lined canal system, induced many ecological constraints to possible snail habitats. Without animal reservoir of infection, control of urinary schistosomiasis or even its eradication looks feasible through a large school case-finding eventually associated with mollusciciding activities in the main foci.