Publication: Experimental and modelling investigations of Opisthorchis viverrini miracidia transmission over time and across temperatures: implications for control
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Issued Date
2017-04-01
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ISSN
18790135
00207519
00207519
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2-s2.0-85014535348
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Mahidol University
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SCOPUS
Bibliographic Citation
International Journal for Parasitology. Vol.47, No.5 (2017), 257-270
Suggested Citation
Pierre Echaubard, Tomas León, Kulwadee Suwanatrai, Jukkrid Chaiyos, Christina S. Kim, Frank F. Mallory, Sasithorn Kaewkes, Robert C. Spear, Banchob Sripa Experimental and modelling investigations of Opisthorchis viverrini miracidia transmission over time and across temperatures: implications for control. International Journal for Parasitology. Vol.47, No.5 (2017), 257-270. doi:10.1016/j.ijpara.2016.10.007 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/42823
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Title
Experimental and modelling investigations of Opisthorchis viverrini miracidia transmission over time and across temperatures: implications for control
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Abstract
© 2017 Australian Society for Parasitology Transmissibility is a significant factor in parasite fitness. The rate and magnitude of parasite transmission affect prevalence and infection intensity in individual hosts and are influenced by environmental factors. In this context, the objectives of this study were: (i) to experimentally assess Opisthorchis viverrini miracidia survival and infectivity over time and across temperatures; and (ii) to combine these experimental results with environmental data to build a key component of a transmission model, identifying seasonal windows of transmission risk in hyper-endemic northeastern Thailand. Five replicates of 50 O. viverrini eggs were randomly distributed and maintained under four temperature conditions (25 °C, 30 °C, 35 °C, 40 °C). Microscopic observations were performed on all experimental units over a period of 3 months to record miracidia motility and mortality trends. Six infection trials were also conducted to assess infectivity of miracidia over time and across temperatures, using observations of egg hatching success and infection rates. Upon completion of experiments, data were integrated into a transmission model to create a transmission risk index and to simulate seasonal transmission risk. Miracidia survival rate and motility decreased steadily with 50% mortality observed after 2 weeks. Hatching and infection success also decreased significantly after 3 weeks. Temperatures over 30 °C were associated with increased mortality and decreased infectivity. When incorporating local environmental parameters into our model, we observed low transmission risk during the dry season and increasing transmission risk at the onset of the rainy season, culminating with the highest risk in September. We believe that our results provide the first estimates of O. viverrini miracidia survival and transmission potential under variable temperature conditions and suggest that high temperature treatment (>40 °C) of fecal waste could be an efficient control strategy.