Schistosomiasis 0.0 / 5 ? OtherHuman ParasitologyUniversityNone Created by: bancroftiCreated on: 21-12-17 15:03 What type of transmission is involved? Active transmission 1 of 22 Name 3 main parasites involved in transmission of schistosomiasis Schistosoma mansoni, S. japonicum, S. haematobium 2 of 22 Are the parasites nematodes or trematodes? Trematodes (flat worms) 3 of 22 The male and female parasites live in copula - how? Female is clasped in the gynaecophoric canal of the male 4 of 22 What is the intermediate host? Snail 5 of 22 What is the definitive host? (plus definition) Human - it is where sexual reproduction occurs. 6 of 22 Name the species of intermediate hosts for urinary, intestinal and Asian intestinal schistosomiasis respectively Bulinus spp., Biomphalaria spp. and Oncomelania spp. 7 of 22 What sort of restriction is there upon the transmission of schistosomiasis? Geographical 8 of 22 What attracts the parasite to the host? Turbulence in the water and chemicals in the skin 9 of 22 Describe step 1 of the life cycle Eggs are eliminated in the faeces or urine (F=S. mansoni and S. japonicum/U=S. haematobium) 10 of 22 Describe step 2 of the life cycle Under optimal conditions, the eggs hatch and release miracidia 11 of 22 Describe step 3 of the life cycle Miracidia swim and penetrate specific snail tissue using proteases 12 of 22 Describe step 4 of the life cycle 2 successive generations of sporocysts (germ-line) 13 of 22 Describe step 5 of the life cycle Cercariae released by snail into water and free-swimming 14 of 22 Describe step 6 of the life cycle Infective cercariae swim and penetrate the skin of the human host 15 of 22 Describe step 7 of the life cycle Cercariae lose their forked tails during penetration to become schistosomulae (48hrs) 16 of 22 Describe step 8 of the life cycle Migrate to portal veins of the livers (die if not), and mature into adults 17 of 22 Describe step 9 of the life cycle Paired adult worms reside in the mesenteric venules in various locations for up to 15yrs 18 of 22 Where do S. japonicum adults reside? Superior mesenteric veins leading to the small intestine 19 of 22 Where do S. mansoni adults reside? Venules draining to the large intestine 20 of 22 Where do S. haematobium adults reside? Venous plexus of the bladder and rectal venules 21 of 22 What causes the most pathology? Eggs 22 of 22
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