Weekly Update (Aug 24, 2017; Wk 17) - West Nile Virus and Culex tarsalis

West Nile Virus Risk –  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of August 20, 2017, areas highlighted in red on the map below have accumulated sufficient heat for C. tarsalis to fly.  Culex tarsalis are also flying in areas highlighted in red, pink or mauve so wear your DEET to stay protected!  Areas highlighted orange or yellow in the map should also be preparing for C. tarsalis flight.

The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer (screen shot of map below).  The Public Health Agency of Canada (PHAC), as of August 12, 2017, reported eight clinical cases (confirmed or probable) in Ontario and one asymptomatic infection in British Columbia.  All eight cases from ON are currently unclassified and two were travel-related. 

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of August 24, 2017, 1218 birds were examined and 58 tested positive for West Nile virus; three from Saskatchewan, two from Manitoba, 15 from Ontario, and 38 from Quebec.

The Public Health Agency of Canada also monitors and posts updates on the status of WNV in Mosquitoes.  As of August 12, 2017, Quebec, Ontario, Manitoba and Saskatchewan reported positive mosquito pools for West Nile Virus.  

A total of 224 positive mosquito pools have been found: 

• 172 from Ontario [Brant County (2), Chatham-Kent (3), Durham Region (4), Eastern Ontario (3), Halton Region (15), Hamilton (4), Haliburton-Kwartha-Pine Ridge District (1), Hastings and Prince Edward Countries (7), Kingston-Frontenac and Lennox and Addington (2), Lambton (1), Middlesex-London (3), Niagara Region (7), Ottawa (11), Oxford County (1), Peel (40), Perth District (2), Peterborough County-City (1), Renfrew County and District (2), Simcoe Muskoka District (1), Toronto (31), Waterloo (2), Wellington-Dufferin-Guelph (2), Windsor-Essex County (21), and York Regional (6)];
• 35 from Manitoba [(Winnipeg (12), Southern (4), Interlake Eastern (5), and Prairie Mountain (12)];
• 9 from Quebec [Montérégie (6), Laval (1), and Mauricie-centre-du-Québec(2)];
• 8 from Saskatchewan.