A Comparison of Kenyan Biomphalaria pfeifferi and B. Sudanica as Vectors for Schistosoma mansoni, Including a Discussion of the Need to Better Understand the Effects of Snail Breeding Systems on Transmission
| Autor: | Horace Ochanda, Ibrahim N. Mwangi, Eric S. Loker, Lijun Lu, Martina R. Laidemitt, Gerald M. Mkoji, Eric A. Lelo, Martin W. Mutuku, Geoffrey M. Maina, Joseph M. Kinuthia, Fredrick Otiato |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Veterinary medicine Kenya Time Factors 030231 tropical medicine Schistosomiasis Snail Disease Vectors Freshwater snail Biomphalaria sudanica Feces 03 medical and health sciences 0302 clinical medicine Biomphalaria pfeifferi biology.animal parasitic diseases medicine Animals Humans Child Ecology Evolution Behavior and Systematics Biomphalaria biology Ecology Schistosoma mansoni biology.organism_classification medicine.disease Schistosomiasis mansoni 030104 developmental biology Parasitology |
| Zdroj: | Journal of Parasitology. 103:669-676 |
| ISSN: | 1937-2345 0022-3395 |
| DOI: | 10.1645/17-72 |
| Popis: | In Kenya, schistosomes infect an estimated 6 million people with30 million people at risk of infection. We compared compatibility with, and ability to support and perpetuate, Schistosoma mansoni of Biomphalaria pfeifferi and Biomphalaria sudanica, 2 prominent freshwater snail species involved in schistosomiasis transmission in Kenya. Field-derived B. pfeifferi (from a stream in Mwea, central Kenya) and B. sudanica (from Nawa, Lake Victoria, in western Kenya) were exposed to S. mansoni miracidia isolated from fecal samples of naturally infected humans from Mwea or Nawa. Juvenile (6 mm shell diameter), young adult (6-9 mm), and adult snails (9 mm) were each exposed to a single miracidium. Schistosoma mansoni developed faster and consistently had higher infection rates (39.6-80.7%) in B. pfeifferi than in B. sudanica (2.4-21.5%), regardless of the source of S. mansoni or the size of the snails used. Schistosoma mansoni from Nawa produced higher infection rates in both B. pfeifferi and B. sudanica than did S. mansoni from Mwea. Mean daily cercariae production was greater for B. pfeifferi exposed to sympatric than allopatric S. mansoni (583-1,686 vs. 392-1,232), and mean daily cercariae production among B. sudanica were consistently low (50-590) with no significant differences between sympatric or allopatric combinations. Both non-miracidia-exposed and miracidia-exposed B. pfeifferi had higher mortality rates than for B. sudanica, but mean survival time of shedding snails (9.3-13.7 wk) did not differ significantly between the 2 species. A small proportion (1.5%) of the cercariae shedding B. pfeifferi survived up to 40 wk post-exposure. Biomphalaria pfeifferi was more likely to become infected and to shed more cercariae than B. sudanica, suggesting that the risk per individual snail of perpetuating transmission in Kenyan streams or lacustrine habitats may differ considerably. High infection rates exhibited by the preferential self-fertilizing B. pfeifferi relative to the out-crossing B. sudanica point to the need to investigate further the role of host breeding systems in influencing transmission of schistosomiasis by snail hosts. |
| Databáze: | OpenAIRE |
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