Expanding geographical distribution of the mosquito, Culex pipiens, in Canada under climate change

An important first step in assessing the possible effects of climate change on the risk of mosquito-borne disease in Canada requires an understanding of the potential shifts in the geographic range of mosquito populations under projected future climate. Risk maps of potential habitat suitability of the mosquito Culex pipiens, an important vector of West Nile and other arboviruses, were created using logistic regression models under conditions of current and projected climate. Current predictions for Culex pipiens distribution are that suitable climatic conditions for the species can be found in southern Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island and southern parts of Newfoundland and Labrador. Projected ranges of the mosquito were obtained using output from models of the Coupled Global Climate Model of the Canadian Centre for Climate Modelling and Analysis and the National Center for Atmospheric Research Community Climate System Model. Using both models, predictions of Culex pipiens range expansion were found for areas further north of the current estimated distribution in Ontario, Quebec, New Brunswick and Newfoundland and Labrador as well as increasing potential habitat suitability in parts of the prairies (Manitoba, Saskatchewan and Alberta) from the 2020s through to 2080s. The degree of range expansion varied according to the greenhouse gas emissions scenario ('A2' - high emissions scenario and 'B1' - low emissions scenario) used in calibrating the climate models. These findings suggest that through its effects on Culex pipiens survival and geographic range, climate change may broaden the range of some mosquito-borne pathogens and as a result expose new human populations to these disease-causing agents. (C) 2011 Elsevier Ltd. All rights reserved.