Identification and mapping of some potential transmission foci of schistosomasis in Maroua, Far North Region, Cameroon


Like many African cities affected by urban schistosomiasis, Maroua in the Far North Region of Cameroon has a moderate level of schistosomiasis transmission, as indicated by human infections. This study was designed to identify and map some potential transmission sites of schistosomiasis in Maroua. Water ponds were surveyed for snail intermediate host of schistosome and mapped using a handheld Global Positioning Systems (GPS). Snail status was assessed via cercaria shedding procedure. The vegetation cover, human water contact activities and some physico-chemical characteristics of the water including pH, temperature, salinity, total dissolve solute (TDS) were measured and documented. Twenty two water ponds were surveyed and 21 of them were found to have at least one of the two identified schistosome snail host species. A total of 658 specimens of snails were collected: 57.45% B. senegalensis and 42.55% B. globosus. Eleven water ponds were found to have both snail host and the 10 other have single species (8 with B. senegalensis and 2 with B. globosus). Ten (1.56%) of the 642 snails were found to shed Schistosoma cercariae: 2.21% in B. senegalensis and 0.71% in B. globosus and they were not significantly different (?2 = 1.431, p= 0.232). The presence of B. senegalensis and B. globosus (two known intermediate snail host of S. haematobium) snail and their infections with Schistosoma suggest possible local transmission of human schistosomiasis in Maroua. Exposure to these water environments may pose infection risk to general population, in particular children who seem to have greater water contact.

Keywords: Mapping, Bulinus senegalensis, Bulinus globosus, schistosomiasis, Maroua, urban area.