A comparative study of Multiple versus Single infection doses of Schistosoma haematobium in Golden hamsters (Mesocricetus auratus)

Schistosoma haematobium is widely distributed in Africa. In Kenya, endemic areas include the upper and the lower regions of the Coast Province, Lake Victoria and the Kano plains. Low infection rates over prolonged periods of time characterize schistosome infections of people living in endemic areas. However, the common laboratory practice is to expose the definitive host to a single high dose. In order to utilize the laboratory results appropriately, it is important to know whether or not a large single infection has similar results to multiple small doses. In this study, immune responses, worm burden, gross and histopathological patterns of multiple infection of S. haematobiumium in the Golden hamster (Mesocricetus auratus) were compared with those of single exposure. Multiple infections with low doses of the parasite did not seem to be protective, as suggested by; more worms, worse gross and histopathology in multiple low dose group compared to single high dose group. Most probably there is an antigenic threshold, which needs to be attained before protective mechanisms come into play. Although necessary for protection, there was no direct correlation between IgG levels and degree of protection. African Journal of Health Sciences Vol. 14 (3-4) 2007: pp. 187-194