The emergence of angiostrongyliasis in the People’s Republic of China: the interplay between invasive snails, climate change and transmission dynamics

Abstract

Summary 1. Only few freshwater snail species transmit the rat lungworm Angiostrongylus cantonensis, which is partially explained by the low likelihood of contact between snails and infected rat faeces. The snail Pomacea canaliculata was introduced into China in 1981 and has become the key intermediate host for A. cantonensis. Thus far, the snail has been recorded in 13 provinces of southern China. 2. We developed a biological model and assessed potential impacts of climate change on the distribution of P. canaliculata and hence the transmission of A. cantonensis. Mean January temperature and snail generation intensity (generation number) were identified as the key factors determining P. canaliculata distribution. Our models predict an increase of 56.9% for the ‘spread’ and a decrease of 40.9% for the ‘establishment’ regions (‘spread’ and ‘establishment’ defined according to a national sampling survey) by the 2030s relative to the present day. 3. Key determinants of A. cantonensis transmission were identified as the generation intensity in the intermediate host, the longevity of A. cantonensis‐infected rats and the dormant period of P. canaliculata. Transmission of A. cantonensis occurs only in areas where the snail’s dormant period is <173.2 days. The potential endemic area of A. cantonensis is predicted to double by the 2030s relative to the present day. 4. The tight fit of our model predictions with data derived from a national sampling survey suggests that biological models hold promise for assessing potential impacts of climate change on infectious diseases once key determinants have been established. Geographical variation analysis may offer an approach to identify areas prone to the spread of vectors, intermediate hosts and parasites in a future warmer China and elsewhere.

Insights from an Integrated View of the Biology of Apple Snails (Caenogastropoda: Ampullariidae)

“…However, it cannot tolerate freezing (Matsukura et al, 2009a), suggesting that the isotherm limiting its southern expansion may be close to its actual southernmost extent (37-38°S; Martín et al, 2001;Seuffert et al, 2010). The northern limit of P. canaliculata, in its nonnative range, is 36°N in Japan (Ito, 2002) and around 31°N in China (Lv et al, 2011). For P. maculata in Europe it is between 40 and 41°N, in the Ebro Delta in Spain (López et al, 2010;Anonymous, 2011); this may also be the limit for P. canaliculata as it may also be present in the Ebro Delta.…”

“…Temperature has therefore been used, among other climatic factors, to predict the potential spread of both P. canaliculata (Baker, 1998;Zhou et al, 2003;Kwong et al, 2008;Lv et al, 2009aLv et al, , 2011EFSA, 2013) and P. maculata (Byers et al, 2013) in their non-native ranges. Ecological niche modeling, combining such climatic models with developmental rates at different temperatures, could be used to predict the isotherms limiting the expansion of ampullariids to higher latitudes, both in their native and non-native ranges (e.g., Lv et al, 2011). At the southernmost limit of its native range P. canaliculata is occasionally exposed to temperatures near 0°C .…”

Molecular cloning, characterization and expression analysis of HSP60, HSP70 and HSP90 in the golden apple snail, Pomacea canaliculata

“…However, the distribution of P. canaliculata is limited by southern or northern latitude, such as 37 S in South America or 31 N in China [15,16]. In our previous research in laboratory, P. canaliculata had a 50% survival rate at 36 C for 21 days but 7% survival rate at 9 C for 35 days [17].…”

Eosinophilic meningoencephalomyelitis in an orangutan (Pongo pygmaeus) caused byAngiostrongylus cantonensis

“…During the past 20 years, the distribution of Z. provisoria has rapidly expanded throughout much of peninsular Florida as demonstrated by collection records at Florida Museum of Natural History. With climate change, further expansion of the range of Z. provisoria and A. cantonensis is expected (Lv et al 2011). Like most snails, Z. provisoria are active nocturnally and during wet weather and estivate in moist, sheltered areas during dry periods.…”