Tedla Shibru (PhD)Lakew Mekuria2018-07-052023-11-082018-07-052023-11-081983-02http://etd.aau.edu.et/handle/123456789/6615The region of Debre Berhan, Where schistosomiasis is not endemic, Vias compared with a' well established focusof S.mansoni, vlonji , with regard to climate, snail habitat s and snail differences in susceptibility and growth rate. In general rain and changes associated with it have influqnce on the snail yopulation but this does not account for the lack of endemic schistosomiasis. Snails from both areas were equally susceptible to infection with §.mansoni. The low mean temperature in Debre Berhan increased the incubation period of the parasite. Mortality rate of Debre Berhan snails was higher than th~£e of wonji snails while the growth rate was vice verSI1. Despite the relatively unfavourable conditions, the possibility of introduction of schistosomiasis to Debre Berhan as a result of environmental modifications that may bring changes in human activities can not be discounted.enBiologyThesis