Species distribution maps of Culex mosquitos, important vectors of West Nile virus

Abstract:

West Nile virus is a mosquito-borne pathogen with a sustained transmission cycle between birds, the reservoir host, and mosquitoes, the viral vector. This virus can spill over into humans if they are bitten by an infected mosquito. After its introduction to the Americas through New York (US) in 1999, West Nile virus established itself throughout North America and is now the largest cause of mosquito-borne disease in humans in both the United States and Canada. Cases have been reported throughout South America, too, reaching as far south as Argentina. Some of the most important mosquito species for transmitting West Nile virus are from the Culex genus. Our current understanding of the geographical distribution of these mosquito species is limited to the state and province level from work published in the early 1980s. Recent data science efforts to curate species presence records in large databases provide a new opportunity to model the contemporary distribution of these vector species. We used mosquito presence data from 1990-2020 from the Global Biodiversity Information Facility and a presence-only ecological niche algorithm called MaxENT to estimate the contemporary distribution of seven Culex species found in North and South America: Cx. erraticus, Cx. nigripalpus, Cx. pipiens, Cx. quinquefasciatus, Cx. restuans, Cx. salinarius, and Cx. tarsalis. We used environmental predictors such as mean annual temperature, precipitation, and land cover as explanatory variables to characterize the mosquito distributions. Our contemporary Culex distribution maps may be used in future West Nile virus risk assessments and can be applied to estimate the risk of other infectious diseases carried by these Culex species.