A conceptual scheme of the environmental transmission pathways of West Nile Virus in the Ontario/Quebec region

West Nile virus (WNV) is an arbovirus of the Flaviviridae viral family transmitted by mosquito bites causing mostly a febrile syndrome but a slight to severe neurological impairment in 20 to 43% of symptomatic human cases in... [ view full abstract ]

West Nile virus (WNV) is an arbovirus of the Flaviviridae viral family transmitted by mosquito bites causing mostly a febrile syndrome but a slight to severe neurological impairment in 20 to 43% of symptomatic human cases in Canada. Since its first detection in Canada in 2002, the geographic dispersal of WNV is expanding and it has been found active sporadically in Canadian Prairies region, as well as Ontario and Québec provinces. In addition, we expect WNV activity to increase with the climate change. The WNV disease is not currently endemic but sporadic and little is known about associated drivers such as, the role of migratory birds in virus transmission. Previous models developed so far have not provided an understanding of this sporadic behavior. Our aim is to develop a conceptual scheme of WNV transmission cycle for the Ontario/Quebec ecoregion that would describe the relationships between various actors involved and support hypotheses generation regarding the sporadic circulation of WNV. A review of scientific literature was used to develop the initial scheme and empirical data specific to the targeted area were used to better tailor the scheme to the Ontario/Quebec region. Specifically, the data included dead wild bird (2002- ) data and WNV in mosquito data (2013-2014). A comprehensive and qualitative conceptual scheme, summarizing current knowledge on the circulation of WNV and identifying key knowledge gaps and plausible hypotheses for WNV sporadic activity. This preliminary study will be an optimal foundation for developing mathematical models for testing hypotheses on the WNV sporadic activity in the Ontario/Quebec region while taking into account the most significant actors involved in the circulation of WNV. As a results it will also support improved prediction capacity in non-endemic WNV areas.