Ecological Niche and Positive Clusters of Two West Nile Virus Vectors in Ontario, Canada

Abstract

West Nile virus (WNV) is a mosquito-borne pathogen associated with uncommon but severe neurological complications in humans, especially among the elderly and immune-compromised. In Northeastern North America, the Culex pipiens/restuans complex and Aedes vexans are the two principal vector mosquito species/species groups of WNV. Using a 10-year surveillance dataset of WNV vector captures at 118 sites across an area of 40,000 km2 in Eastern Ontario, Canada, the ecological niches of Cx. pipiens/restuans and Aedes vexans were modeled by random forest analysis. Spatiotemporal clusters of WNV-positive mosquito pools were identified using Kulldorf’s spatial scan statistic. The study region encompasses land cover types and climate representative of highly populated Southeastern Canada. We found highest vector habitat suitability in the eastern half of the study area, where temperatures are generally warmer (variable importance > 0.40) and residential and agricultural cropland cover is more prominent (variable importance > 0.25). We found spatiotemporal clusters of high WNV infection rates around the city of Ottawa in both mosquito vector species. These results support the previous literature in the same region and elsewhere suggesting areas surrounding highly populated areas are also high-risk areas for vector-borne zoonoses such as the WNV.

Spatiotemporal analysis of West Nile virus infection in the human population based on arboviral detection testing of blood donations

“…Since 2002, Public Health Ontario (PHO) has collected data on mosquito surveillance activities conducted by public health units in Ontario, which comprise mosquito capture and identi cation of 22 species/species groups. Capture is performed using the protocol as described in Talbot et al (2023) 56 . Brie y, Culex pipiens/restuans are prioritized over all other species, and Ae.…”

“…We followed the approach of Talbot et al (2023) 56 to process land cover and climate data for subsequent ecological niche models. Land cover data for the year 2013 were obtained from Agriculture and Agri-Food Canada (AAFC) and the United States Geological Survey (USGS) with a resolution of 30 meters across our study area.…”

“…We followed the approach of Talbot et al (2023) 56 . The two studied mosquito species were observed at least once in the vast majority of the 3,010 sampling locations over the study period (2,783 for Ae.…”