Culex tritaeniorhyncus, a mosquito native to northern Asia, is the primary vector of Japanese encephalitis virus (JEV). A relative of dengue, yellow fever and West Nile, this flavivirus infects nearly 68,000 humans each year, triggering incurable brain inflammation that causes death in up to 30 per cent of the cases and permanent neurological or psychiatric damage in another 30 to 50 per cent.
The World Health Organization estimates that more than 3 billion people in 24 countries in Southeast Asia and the Western Pacific risk exposure to JEV infection. But as with many arboviruses, the distribution of its arthropod vectors is poorly documented. Here, the authors combined 225 Cx. tritaeniorhyncus records from GBIF.org along with data from VectorMap and 21st-century scientific literature, in hope of improving knowledge of where the species occurs and mapping environmentally suitable areas for incidence of JEV.
In addition to predicting high suitability in India, Nepal and China, the resulting models draw specific attention to highly suitable regions in northwest India, southeast Pakistan, northern Japan and southeast Russia where records of Cx. tritaeniorhyncus are lacking. While higher resolution occurrence data could improve the maps’ ability to assess risks, this research could help to target key monitoring sites, inform vector control measures and supplement education campaigns aimed at preventing the spread of JEV in environmentally suitable locales.