Infection sources Patients reservoir host - animal reservoirs cowS, pigs(S japonicum) Rodents, monkeys, and baboons have been found infected in nature, but the role of these animals as reservoirs does not seem to be epidemiologically Important
11 Infection sources Patients reservoir host- animal reservoirs cows,pigs(S. japonicum) Rodents, monkeys, and baboons have been found infected in nature, but the role of these animals as reservoirs does not seem to be epidemiologically important
mode of transmission 3 links in parasitic epidemiology 1. The endemicity of schistosomiasis depends on the urban disposal of urine(s haematobium) and feces(S. mansoni, S japonicum, s intercalatum, s. mekongi) 2. the presence of suitable snail hosts 3. human exposure to cercariae
mode of transmission 3 links in parasitic epidemiology 1. The endemicity of schistosomiasis depends on the urban disposal of urine (S. haematobium) and feces (S. mansoni, S. japonicum, S. intercalatum, S. mekongi), 2. the presence of suitable snail hosts 3. human exposure to cercariae
The freshwater snail intermediate hosts are Biomphalaria spp in Africa and Biomphalaria glabrata(australorbis and tre Snail opicarbis in South america and the West indies 13
13 The freshwater snail intermediate hosts are Biomphalaria spp in Africa and Biomphalaria glabrata (Australorbis) andTropicarbis in SouthAmerica and theWest Indies. Snail
Susceptible population Humans are susceptible to the schistosoma young adults Summer and autumn 14
14 Susceptible population Humans are susceptible to the Schistosoma. young adults Summer and autumn
Schistosoma life cycle Adult worms in 6 weeks human vesical or mesenteric veins 5to 9 weeks Schistosomula Egg first parasite stage in urine or stools in humans 72 hours Cercaria free-living in fresh water Miracidium free (infective stage) iving in fresh water Freshwater snail asexual
Schistosoma life cycle 4 to 7 weeks 72 hours 6 weeks 5 to 9 weeks