Tag: West Nile virus

West nile virus risk

The following is offered to help predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies. This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in Figure 1 but the unusual heat across the prairies greatly accelerated mosquito development!

As of July 25, 2021 (Fig. 1), C. tarsalis development has now reached the point that adults are predicted to be flying across the south of the prairies from Manitoba to Alberta. Outdoor enthusiasts falling within areas highlighted red (i.e., areas that have accumulated sufficient heat accumulation for C. tarsalis to emerge) should wear DEET to protect against WNV! Because of the continued high temperatures, areas highlighted yellow or orange in the map below (as of July 25) should also start to use DEET this week! IF C. tarsalis is present in an area where WNV is active, it may take as little as 14 days for adults to become fully infective with the current warm weather (Fig. 2).

Figure 1. Predicted development of Culex tarsalis across the Canadian prairies (as of July 25, 2021).
Figure 2. Predicted days for virulence of West Nile Virus to develop within Culex tarsalis, if present within a region (as of July 26, 2021).

The Public Health Agency of Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance. Link here to access their most current weekly update (reporting date June 21, 2021; retrieved July 29, 2021). The screenshot below (retrieved 29Jul2021) serves as a reference and reports one human case of WNV, a positive wild bird, and positive mosquito pools in Ontario.

Bird surveillance continues to be an important way to detect and monitor West Nile Virus. The Canadian Wildlife Health Cooperative (CWHC) works with governmental agencies (i.e., provincial laboratories and the National Microbiology Laboratory) and other organizations to report the occurrence of WNV. Dead birds retrieved from areas of higher risk of West Nile Virus are tested for the virus. A screenshot of the latest reporting results posted by Canadian Wildlife Health Cooperative is below (retrieved 29Jul2021).

Anyone keen to identify mosquitoes will enjoy this pictorial key for both larvae and adults which is posted on the Centre for Disease Control (CDC) website but sadly lacks a formal citation other than “MOSQUITOES: CHARACTERISTICS OF ANOPHELINES AND CULICINES prepared by Kent S. Littig and Chester J. Stojanovich” and includes Pages 134-150. The proper citation may be Stojanovich, Chester J. & Louisiana Mosquito Control Association. (1982). Mosquito control training manual. pp 152.

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (reporting date July 12-18, 2020; retrieved Aug 13, 2020). The screenshot below (retrieved Aug 13, 2020) serves as reference but access that Health Canada information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of August 9, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 9, 2020).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 5-11, 2020; retrieved July 30, 2020). The screenshot below (retrieved July 30, 2020) serves reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 30, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 30, 2020).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020; retrieved July 23, 2020). The screenshot below (retrieved July 23, 2020) serves reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 19, 2020, areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 19, 2020).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020). The screenshot below was retrieved 16Jul2020 as reference but access that information here.

This image has an empty alt attribute; its file name is 2020Jun28-Jul04_WNV_Weekly_HealthCanada-1024x593.png

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of July 13, 2020, areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 13, 2020).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 4, 2020). The screenshot below was retrieved 09Jul2020 as reference but access that information here.

The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below.  As of July 8, 2020, areas highlighted yellow are approaching sufficient heat accumulation for mosquitoes to emerge.  Plan to protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 8, 2020).

West Nile Virus and Culex tarsalis

West Nile Virus Risk
Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (August 10, 2019). The screenshot below was retrieved 22Aug2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, 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 18, 2019, areas highlighted orange are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red in the map below should now have C. tarsalis in flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 18, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).  For example, as of August 18, 2019, areas highlighted orange in the map below had C. tarsalis flying that required 18-20 days to become fully infective.

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (August 3, 2019). The screenshot below was retrieved 15Aug2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, 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 11, 2019, areas highlighted orange are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red in the map below should now have C. tarsalis in flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 11, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).  For example, as of August 11, 2019, Foremost AB was predicted to only take 16-18 days for C. tarsalis to become fully infective.

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 27, 2019). The screenshot below was retrieved 09Aug2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of July 28, 2019, areas highlighted orange are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red in the map below should now have C. tarsalis in flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 5, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).  For example, as of August 8, 2019, Winnipeg MB was predicted to only take 16-18 days for C. tarsalis to become fully infective.

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 20, 2019). The screenshot below was retrieved 01Aug2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of July 28, 2019, areas highlighted orange are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red in the map below should now have C. tarsalis in flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 28, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).  For example, as of July 28, 2019, Altona MB is predicted to only take 16 days for C. tarsalis to become fully infective!

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 13, 2019). The screenshot below was retrieved 25Jul2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted yellow in the map below (Fig. 2) are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted lime green should be preparing for C. tarsalis flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 21 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Reminder – In 2018, there were 426 human clinical cases of West Nile virus (WNV) in Canada (Fig. 1). 

Figure 1. Geographic distribution of WNV human clinical cases and asymptomatic infections in Canada, 2018.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (11Jul2019).  Access the full map at https://www.canada.ca/en/public-health/services/publications/diseases-conditions/west-nile-virus-surveillance/2018/november-11-december-15-week-46-50.html

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 6, 2019). The screenshot below was retrieved 18Jul2019 as reference but access that information here.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  Take note of the provincial distribution of positive WNV birds in 2018 (table posted below as reference).

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 2). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted yellow in the map below (Fig. 2) are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted lime green should be preparing for C. tarsalis flight.

Figure 2. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 14, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 3).

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  In 2018, there were 426 human clinical cases of West Nile virus (WNV) in Canada (Fig. 1). 

Figure 1. Geographic distribution of WNV human clinical cases and asymptomatic infections in Canada, 2018.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (11Jul2019).  Access the full map at https://www.canada.ca/en/public-health/services/publications/diseases-conditions/west-nile-virus-surveillance/2018/november-11-december-15-week-46-50.html

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (June 29, 2019). The screenshot below was retrieved 11Jul2019 as reference but access that information here.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  Take note of the provincial distribution of positive WNV birds in 2018 (table posted below as reference).

The following is offered to predict when Culex tarsalis will begin to fly (Fig. 2) across the Canadian prairies. Protect yourself by wearing DEET!  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted lime green in the map below (Fig. 2) are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge soon.  

Figure 2. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 7, 2019).

Once the adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – as quickly as 20-22 days, given the current environmental conditions in the highlighted areas of the map below (Figure 3).

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.  Areas highlighted yellow then orange are approaching sufficient heat accumulation for mosquitoes to emerge while mosquitoes will be flying in areas in red so wear DEET to stay protected! 

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 7, 2018) on 2018 testing (screenshot retrieved 25Jul2018 provided below for reference only).

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of June 28, 2018, 872 birds were examined and nine have tested positive for West Nile virus. View a screen shot of the summary of those results below:

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.  Areas highlighted yellow then orange are approaching sufficient heat accumulation for mosquitoes to emerge while mosquitoes will be flying in areas in red so wear DEET to stay protected! 

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (July 7, 2018) on 2018 testing (screenshot retrieved 25Jul2018 provided below for reference only).

Reminder – The 2017 WNV surveillance map for human cases is available here but a screenshot is posted below for reference.

Figure 1.  As of surveillance week 49, ending December 9, 2017, the preliminary data indicated 197 human cases of WNV in Canada; twenty-five from Québec, 159 from Ontario, five from Manitoba, seven from Alberta, and one from British Columbia.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of June 28, 2018, 642 birds were examined and zero have tested positive for West Nile virus. 

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.  Areas highlighted yellow then orange are approaching sufficient heat accumulation for mosquitoes to emerge while mosquitoes will be flying in areas in red so wear DEET to stay protected! 

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  Link here to access the most current weekly update (June 30, 2018) on 2018 testing (screenshot retrieved 18Jul2018 provided below for reference only).

Reminder – The 2017 WNV surveillance map for human cases is available here but a screenshot is posted below for reference.

Figure 1.  As of surveillance week 49, ending December 9, 2017, the preliminary data indicated 197 human cases of WNV in Canada; twenty-five from Québec, 159 from Ontario, five from Manitoba, seven from Alberta, and one from British Columbia.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of June 28, 2018, 642 birds were examined and zero have tested positive for West Nile virus. 

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.  Areas highlighted yellow then orange are approaching sufficient heat accumulation for mosquitoes to emerge while mosquitoes will be flying in areas in red so wear DEET to stay protected!

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  The 2017 WNV surveillance map for human cases is available here but a screenshot is posted below for reference.

Figure 1.  As of surveillance week 49, ending December 9, 2017, the preliminary data indicated 197 human cases of WNV in Canada; twenty-five from Québec, 159 from Ontario, five from Manitoba, seven from Alberta, and one from British Columbia.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of June 28, 2018, 642 birds were examined and zero have tested positive for West Nile virus. 

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. 

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 13 2017, areas highlighted in red on the map below have accumulated sufficient heat for C. tarsalis to fly.  Areas highlighted in red, orange and even yellow will have C. tarsalis flying so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer and three cases of viral West Nile have been reported so far (as of August 5, 2017).  All cases were reported from Ontario (in Timiskaming and Windsor-Essex).

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of August 17, 2017, 1113 birds were examined and 48 have tested positive for West Nile virus; one from Saskatchewan, two from Manitoba, 13 from Ontario, and 32 from Quebec.

The Public Health Agency of Canada also monitors and posts updates on the status of WNV in Mosquitoes.  As of July 22, 2017, Quebec, Ontario, Manitoba and Saskatchewan have reports of positive mosquito pools of West Nile Virus.  A total of 47 positive mosquito pools have been found: 

  • 33 from Ontario [Peel Regional (5), Toronto (6), Halton(5), Haliburton-Kwartha-Pine Ridge District(1), Simcoe Muskoka District (1), Windsor-Essex County (6), Eastern Ontario (1), Durham Reginal (1), Hamilton (1), Haliburton-Kawarta-Pine Ridge district (1), Hastings and Prince Edward Countries (2), and York Regional (3)];  
  • 11 from Manitoba [(Winnipeg (3), Southern (2), Interlake eastern (1), and Prairie Mountain(5)]; 
  • 2 from Quebec [Montérégie (1), Laval (1)], and 
  • 1 from Saskatchewan. 

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 July 30, 2017, areas highlighted in red on the map below have accumulated sufficient heat for C. tarsalis to fly.  Areas highlighted in red, orange and even yellow will have C. tarsalis flying so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer and two cases of viral West Nile have been reported so far (as of July 22, 2017).  Both cases were reported from Ontario (in Timiskaming and Windsor-Essex).

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of August 3, 2017, 964 birds were examined and 23 have tested positive for West Nile virus; two from Manitoba, eight from Ontario, and 13 from Quebec.


The Public Health Agency of Canada also monitors and posts updates on the status of WNV in Mosquitoes.  As of July 22, 2017, Quebec, Ontario, Manitoba and Saskatchewan have reports of positive mosquito pools of West Nile Virus.  A total of 47 positive mosquito pools have been found: 

  • 33 from Ontario [Peel Regional (5), Toronto (6), Halton(5), Haliburton-Kwartha-Pine Ridge District(1), Simcoe Muskoka District (1), Windsor-Essex County (6), Eastern Ontario (1), Durham Reginal (1), Hamilton (1), Haliburton-Kawarta-Pine Ridge district (1), Hastings and Prince Edward Countries (2), and York Regional (3)];  
  • 11 from Manitoba [(Winnipeg (3), Southern (2), Interlake eastern (1), and Prairie Mountain(5)]; 
  • 2 from Quebec [Montérégie (1), Laval (1)], and 
  • 1 from Saskatchewan. 

Weekly Update – 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 July 23, 2017, areas highlighted in yellow on the map below have accumulated sufficient heat for the initial C. tarsalis to begin to fly.  Areas highlighted in orange will have C. tarsalis flying so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer but zero cases of viral West Nile have been reported so far (June 25-July 15, 2017).  

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of July 20, 2017, 833 birds were examined and eight have tested positive for West Nile virus; four from Ontario, one from Saskatchewan, and one from Quebec. 

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 July 13, 2017, areas highlighted in yellow on the map below have accumulated sufficient heat for the initial C. tarsalis to begin to fly whereas areas highlighted in orange have to C. tarsalis flying so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer but zero cases of viral West Nile have been reported so far (June 25-July 1, 2017).  

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of July 20, 2017, 833 birds were examined and eight have tested positive for West Nile virus; four from Ontario, one from Saskatchewan, and one from Quebec. 

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 July 9, 2017, areas highlighted in yellow on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!




The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  In 2016, 104 human clinical cases of West Nile Virus were reported.  The map of clinical cases of West Nile Virus in Canada in 2017 is updated through the summer but zero cases of viral West Nile have been reported so far (June 25-July 1, 2017).

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of July 6, 2017, 729 birds were examined and six have tested positive for West Nile virus in Ontario. 

Weekly Update – 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 21, 2016, areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!




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 2016 is posted (as of July 23, 2016) while a screen shot is provided below (posted August 22, 2016).



The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 22, 2016, 36 birds were submitted for testing and two have tested positive for West Nile virus in Ontario. 

Weekly Update – 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 14, 2016, areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!


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 2016 is posted (as of July 23, 2016) while a screen shot is provided below (retrieved August 17, 2016).

WN Cases Canada.jpg

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 17, 2016, 32 birds were submitted for testing yet none have tested positive for West Nile virus. 

Weekly Update – 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 7, 2016, areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!

GDD Base 14.3 Aug 7


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 2016 is posted (as of July 23, 2016) while a screen shot is provided below (retrieved August 10, 2016).


WN Cases Canada.jpg

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 3, 2016, 27 birds were submitted for testing yet none have tested positive for West Nile virus. 

Weekly Update – 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 July 31, 2016, areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!



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 2016 is posted (as of July 23, 2016) while a screen shot is provided below (retrieved August 3, 2016).


The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 3, 2016, 27 birds were submitted for testing yet none have tested positive for West Nile virus. 

Weekly Update – 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 July 24, 2016, areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!




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 2015 is posted while a screen shot is provided below.



The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of July 27, 2016, 27 birds were submitted for testing yet none have tested positive for West Nile virus. 

Weekly Update – 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 July 17, 2016, areas highlighted in yellow or orange on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!





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 2015 is posted while a screen shot is provided below.



The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of July 7, 2016, 20 birds were submitted for testing yet none have tested positive for West Nile virus.