A spatiotemporal epidemiological investigation of the impact of environmental change on the transmission dynamics of Echinococcus spp. in Ningxia Hui Autonomous Region, China

International audience; Echinococcoses are parasitic diseases of major public health importance globally. According to recent estimates, the geographical distribution of Echinococcus spp. infections is expanding and becoming an emerging and re-emerging problem in several regions of the world. Using geographic information systems and remote sensing technologies, we explored the role of environmental factors in determining the spatiotemporal variation of human echinococcosis risk in Ningxia Hui Autonomous Region, which is a hyper-endemic province for echinococcoses. Data on echinococcosis cases were obtained from a hospital-based retrospective survey undertaken between 1 January 1994 and 31 December 2013. Land cover maps of the region were created using a range of high-quality remote sensing images with approximately 30-meter spatial resolution. Data on climatic factors were obtained from 11 local meteorological stations. The inverse distance weighted interpolation method was applied to obtain data for those locations where there were no meteorological observations locally available. Bayesian spatiotemporal conditional autoregressive models were developed at the township-level to quantify the relationship between monthly cases of human echinococcoses and environmental factors. The results of the study indicate that the land cover patterns and landscape characteristics in the province were greatly altered during the study period. We also found a significant spatial heterogeneity in the prevalence of human echinococcoses across the province. Models revealed significant positive association between human cystic echinococcosis infection and mean temperature in winter (lag-10), and also negative associations between human alveolar echinococcosis and moving averages calculated for bareland, mean temperature and mean temperature in winter. Environmental determinants of human echinococcoses can be used to develop and refine initiatives local and national initiatives to reduce the medical, social and economic burden of the infection.