Predicting the spatial distribution of Biomphalaria straminea, a potential intermediate host for Schistosoma mansoni, in China

Abstract

Schistosomiasis is one of the most prevalent parasitic diseases impacting human health in the tropics and sub-tropics. The geographic distribution of Schistosoma mansoni, the most widespread species, includes areas in Africa, the Middle East, South America and the Caribbean. Snails of the genus Biomphalaria act as intermediate host for S. mansoni. Biomphalaria straminea is not indigenous in China but was accidentally introduced to Hong Kong from South America and has spread to other habitats in the southern parts of the country. This species is known for its great dispersal capacity that highlights the importance of the snail as a potential host for S. mansoni in China. In this connection, although no such infection has been recorded in the field so far, the continuous expansion of China's projects in endemic areas of Africa and import of the infection via returning workers or visitors deserve attention. The purpose of this study was to map and predict the spatial distribution of B. straminea in China. Snail occurrence data were assembled and investigated using MaxEnt software, along with climatic and environmental variables to produce a predictive risk map. Of the environmental variables tested, the precipitation of warmest quarter was the most contribution factor for snail's spatial distribution. Risk areas were found in southeastern China and it is expected that they will guide policies and control programmes to potential areas area of snail abundance and used for spatial targeting of control interventions for this invasive species.

Distribution and current infection status of Biomphalaria straminea in Hong Kong

“…The identification of two shell colours of B. straminea contrasts with the previous field investigations in Hong Kong; either the colour variants were missed in the earlier studies or a new phenotype has evolved in the last 30 years [14, 15, 28–30]. A previous pigmentation study supported the existence of B. straminea with both shell colours [31].…”

“…It has also been predicted that B. straminea will spread to Pearl River Delta areas in Guangdong, southern parts of Guangxi and Fujian provinces, as well as the North of Taiwan [30]. These data suggest that the B. straminea situation should be closely monitored.…”

“…Ever since the first report of identification of B. straminea in Hong Kong back in the 1970s, there have always been concerns about S. mansoni infection breakouts southern China [14–20, 28–30]. In the north-east of Brazil, the prevalence of S. mansoni infection in B. straminea ranges from 11 to 24% [38, 39], while artificial exposures of S. mansoni to B. straminea in the laboratory have shown low infectivity, with prevalence ranging from 1.2 to 1.6% depending on the strain of miracidia being tested [40].…”

The complete mitochondrial genome of invasive species Biomphalaria straminea (Planorbidae: Biomphalaria) and phylogenetic analysis

“…This invasive species has a tendency of expansion in the further in China. It has been predicted that B. straminea will spread to Pearl River Delta of Guangdong, southern parts of Guangxi and Fujian provinces, and the North of Taiwan (Habib et al 2016). However, in recent years, it is a sharp increase in the number of Africa-aid projects, and more cases infected with schistosomiasis have been detected when the workers returned to China from Africa (Zhou et al 2011).…”

Padrão de distribuição da diversidade genética molecular e espacial de Biomphalaria spp. e sua relação com a ocorrência da esquistossomose na região do Médio Paranapanema, estado de São Paulo

“…No Brasil, a utilização dos SIGs aplicados em estudos de distribuição de caramujos hospedeiros intermediários de S. mansoni em relação a ocorrência da esquistossomose, foram principalmente utilizados em áreas de alta endemicidade no estado da Bahia (BAVIA et al, 1999;CARDIM et al, 2011), Pernambuco (ALMEIDA et al, 2003GOMES et al, 2012GOMES et al, , 2018, Minas Gerais (GUIMARÃES et al, 2009(GUIMARÃES et al, , 2012FONSECA et al, 2014) BARBOSA et al, 2016, CARVALHO et al, 2017GOMES et al, 2018). Outros exemplos de sua aplicação são os estudos da distribuição da espécie Biomphalaria no Uruguai, Argentina (RUMI et al, 2017), China e na África (PEDERSEN et al, 2014;HABIB et al, 2016;YANG et al, 2018;FAN et al, 2018). MARENGO et al (2012MARENGO et al ( , 2014 fizeram estudos de previsão de aumento de precipitação para as próximas décadas no Brasil, em função das alterações climáticas globais, que provavelmente terão como consequência o aumento do volume de água de todas as bacias hidrográficas brasileiras.…”