Compatibility of Schistosoma japonicum from the hilly region and Oncomelania hupensis hupensis from the marshland region within Anhui, China

Abstract

Schistosome japonicum remains one main public concern in China. This is exemplified in the hilly region in Anhui Province, where rodents have served as reservoirs for the parasite and no effective intervention could target such wild animals. The closer relationship between the hilly region and the near marshland induces the worry of spread of the hill parasite to the marshland region. Therefore, the level of snail-parasite compatibility between the hill parasite and snail populations from the Yangtze River valley was investigated. The results of this study demonstrated that both the hill (Shitai, Anhui) and the marshland (Wuxi, Jiangsu) strains of parasite were more infective to the marshland strains of snail (Zongyang and Hexian, Anhui) than to the hill strain of snail (Shitai, Anhui). When snails were individually exposed to one single miracidium, the longest prepatent period for cercarial development was observed in the combination of Shitai schistosome/Shitai snail. A nocturnal cercarial emergence pattern was observed for the hill parasite, either harbored in the hill or the marshland strain of snails. The results suggested a high compatibility between the marshland strains of snail and both the hill and the marshland strains of parasite. This would have practical implications. Moreover, the fact of the lower compatible relationship between the hill parasite and its local intermediate hosts warranted more studies.

Circadian rhythms of trematode parasites: applying mixed models to test underlying patterns

“…), which infect approximately 200 million people worldwide (Fenwick, 2012), emerge en masse from aquatic snails at times that parallel peak activity of local villagers (Silva et al 1995;Ahmed et al 2006;Mintsa-Nguéma et al 2014). Intriguingly, parasite emergence patterns vary regionally in association with differences in village-specific behaviours as well as the role of alternative hosts (N'Goran et al 1997;Lu et al 2009;Su et al 2013;Wang et al 2014). Su et al (2013) reported that S. japonicum was more likely to emerge nocturnally in regions where rodents served as important reservoir hosts, whereas strains maintained in the laboratory emerge during the day.…”

Detecting genotyping errors at Schistosoma japonicum microsatellites with pedigree information

“…Individual snails, with no previous schistosome infections, were individually exposed to a single miracidium and later checked for infection of schistosome with a shedding experiment. For the details in procedure, see the work in [ 24 , 25 ]. As the parasite undergoes only asexual reproduction within snail hosts these individually laboratory-infected snails therefore each harbored only clonal cercariae of the same gender and genotype.…”

The influence of natural factors on the spatio-temporal distribution of Oncomelania hupensis

“…Water is one of the necessary conditions for snails to breed and calve. Young snails often live in water surroundings, and adult snails living in areas of soil with plenty of water and food (Wang et al, 2014). Usually, the annual rainfall in areas with snail distribution is greater than 750 mm (Yang et al, 2009a(Yang et al, , 2009b.…”

“…Studies of the influence of natural factors on the spatio-temporal distribution of snails have mainly focused on statistical analysis, correlation analysis and normal regression analysis, generalized linear models, generalized additive models, and Bayesian models (Wang et al, 2014;Sun et al, 2011;Liu et al, 2016;Hu et al, 2013;Yang et al, 2009a,b). These studies all ignored some attributions (spatial autocorrelation, spatial heterogeneity, scale-dependent and so on) of schistosomiasis and snail (its host) data, and the spatio-temporal heterogeneity of the effects of natural factors on snails, which might lead to some biased research conclusions and a limited understanding of these effects.…”