West Nile Virus and Other Mosquito-Borne Diseases National Surveillance Report - June 25 to July 1, 2017 (Week 26)

West Nile virus

Canada

Humans

As of surveillance week 26, ending on July 1, 2017, the Public Health Agency of Canada (PHAC) has not been informed of any human cases of West Nile virus by provinces and territories since the beginning of the 2017 season in Canada. 

Mosquitoes

In week 26 there have been 5 positive tests of West Nile Virus, 3 from Ontario (Peel Regional (1), Toronto (1), and Windsor-Essex County (1)), and 2 from Manitoba (Winnipeg (1), Southern (1)). As of initial surveillance, PHAC has received 2,284 mosquito pools data tested for West Nile virus in Canada. All were reported in Ontario and Manitoba.

Birds

The Canadian Wildlife Health Cooperative has tested 6 dead birds for West Nile virus: one in Saskatchewan, four in Ontario, and one in Quebec. Of these, three were positive for WNV and all were reported in Campbellsville, Ontario. 

Domestic Animals

The Canadian Food Inspection Agency has not reported any domestic animals tested positive for West Nile virus since the beginning of the 2017 season.

United States and U.S. territories

As of July 1, 2017, there are no human cases of West Nile virus in the United States and U.S territories, reported by the Centers for Disease Control and Prevention.

Detailed information can be accessed via the CDC web site.

Europe and Neighbouring Countries

As of July 1, 2017, there are no human cases of West Nile virus reported in the European Union and neighbouring countries.

Detailed information can be accessed via the ECDC web site.

Other Mosquito-borne Diseases

Canada

Eastern Equine Encephalitis virus:

No human cases of eastern equine encephalitis virus have been reported to the Public Health Agency of Canada since the 2017 season.

California Serogroup virus:

During surveillance week 26, no human cases/exposures of California serogroup virus were diagnosed by the National Microbiology Laboratory in the Public Health Agency of Canada.

Since January 1, 2017, 9 human cases of laboratory-confirmed cases/exposures of California serogroup virus were diagnosed by the National Microbiology Laboratory in Canada: Alberta (2), Saskatchewan (1), and Quebec (6).  Of these cases, four were further classified as Jamestown Canyon virus and the rest as unknown.

Figure 1: Geographic distribution of West Nile virus human clinical cases in Canada, as of July 1, 2017

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Figure 1: Text Equivalent

Map showing geographic distribution of human clinical cases of WNV in Canada.

 As of surveillance week 26, ending July 1, 2017, there are no human clinical cases of WNV in Canada.

FIGURE 2: West Nile virus human clinical cases and asymptomatic infections by province/ territory and by report week, as of July 1, 2017 

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*West Nile virus clinical cases and asymptomatic infections are grouped by report week, based on episode date.  Episode date could include one of the following: onset date, diagnosis date, lab sample date or reporting date.

Figure 2: Text Equivalent

As of week 26, ending July 1,  2017, there are no West Nile virus human clinical cases and asymptomatic infections in Canada.

Table showing WNV Human clinical cases and Asymptomatic Infections in Canada, by Province/ Territory and by Report week, as of week 26, ending July 1, 2017 season
  Week 26:  June 25 to July 1, 2017
West Nile virus neurological syndrome West Nile virus non-neurological syndrome Unclassified/
unspecified
Total clinical cases Number of travel-related cases West Nile virus asymptomatic infection
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0

FIGURE 3: West Nile virus human clinical cases and asymptomatic infections by report week for selected years, in Canada

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Figure 3: Text Equivalent
Table showing WNV Human Clinical cases and Asymptomatic Infections in Canada, by Report week for selected years
  Report Week
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Total
2017 0 0 0 0 0 0 0 0 0 0                                                  
2016 0 0 0 0 0 0 0 0 0 0                                               0
2015 0 0 0 0 0 0 0 0 0 0 0 1 1 2 1 0 2 7 4 8 9 11 4 8 11 8 4 0 1 0 0 0 0 0 82
2013 0 0 0 0 0 1 1 0 0 0 1 2 2 5 5 6 9 10 21 16 14 12 7 2 1 0 1 1 0 0 0 0 0 1 118
2012 0 0 0 0 0 0 1 0 0 0 3 5 11 16 27 53 63 57 43 43 45 24 30 14 9 5 1 0 0 0 0 0 0 0 450
2007 0 0 0 0 0 0 2 2 3 4 11 35 36 72 139 424 471 443 287 182 116 71 30 18 10 11 5 4 2 0 0 0 0 0 2378
Table 1: West Nile virus human clinical cases and asymptomatic infections by province/territory for the current report week and year to date, 2017 season
  Week 26:  June 25 to July 1, 2017
West Nile virus neurological syndrome West Nile virus non-neurological syndrome Unclassified/
unspecified
Total clinical casestable 1 Footnote 1 Number of travel-related casestable 1 Footnote 2 West Nile virus asymptomatic infectiontable 1 Footnote 3
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0
Total 0 0 0 0 0 0
  Year to date:  January 1 to July 1, 2017
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0
Total 0 0 0 0 0 0

Table 1 Footnotes

table 1 Footnote 1

Total clinical cases is the sum of both probable and confirmed: West Nile virus neurological and non-neurological syndromes, along with any unclassified or unspecified cases.

Return to table 1 footnote 1 referrer

table 1 Footnote 2

Likely related to travel outside the Province/Territory. These cases are included in either the total clinical cases or West Nile virus asymptomatic infections.

Return to table 1 footnote 2 referrer

table 1 Footnote 3

Satisfies West Nile virus diagnostic test criteria in the absence of clinical criteria. This category could include asymptomatic blood donors whose blood is screened using a nucleic acid amplification test, by blood operators (i.e. Canadian Blood Services or Hema-Quebec) and is subsequently brought to the attention of public health officials. Blood operators in Canada perform a supplementary West Nile virus specific nucleic acid amplification test following any positive donor screen test result.

Return to table 1 footnote 3 referrer

Table 2: Number of mosquito pools tested for West Nile virus and number of positive mosquito pools by province/territory, 2017 season
Province Year to date: January 1 to July 1, 2017  
Number of positive mosquito pools Number of mosquito pools tested Percentage of positive mosquito pools (%)
Quebec - - -
Ontario 3 2160 0.14
Manitoba 2 124 1.6
Saskatchewan - - -
Alberta - - -
British Columbia - - -
Newfoundland and Labrador - - -
Prince Edward Island - - -
Nova Scotia - - -
New Brunswick - - -
Yukon Territory - - -
Northwest Territory - - -
Nunavut - - -
Total 5 2284 .30
Table 3: Number of West Nile virus positive mosquito pools/ total number of WNV mosquito pools tested by report week and by province/ territory, 2017 seasontable 3 Footnote 1
Province / Territory Report week of 2017
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Newfoundland and Labrador 0 0 0 0 0 0 0 0                            
Prince Edward Island 0 0 0 0 0 0 0 0                            
New Brunswick 0 0 0 0 0 0 0 0                            
Nova Scotia 0 0 0 0 0 0 0 0                            
Quebec 0 0 0 0 0 0 0 0                            
Ontario 13 15 43 84 194 299 718 794                            
Manitoba 0 0 0 0 15 45 48 16                            
Saskatchewan 0 0 0 0 0 0 0 0                            
Alberta 0 0 0 0 0 0 0 0                            
British Columbia 0 0 0 0 0 0 0 0                            
Yukon Territory 0 0 0 0 0 0 0 0                            
Northwest Territory 0 0 0 0 0 0 0 0                            
Nunavut 0 0 0 0 0 0 0 0                            
Total 13 15 43 84 209 344 766 810                            

table 3 Footnotes

table 3 Footnote 1

Detailed West Nile virus mosquito surveillance data can be accessed through Provincial/ Territorial websites

Return to table 3 footnote 1 referrer

Figure 4: Reported number of dead birds tested positive for West Nile virus by province/ territory and by report week, 2017 season in Canada 

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Figure 4: Text Equivalent

As of week 26, ending July 1 in 2017, there are 3 West Nile virus cases in birds, in Canada.

Table showing the Reported number of dead birds tested positive for WNV in Canada, by Province/ Territory and by Report week, 2017 season
  Report Weeks of 2017
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Total
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0                                               0
Prince Edward Island 0 0 0 0 0 0 0 0 0 0                                               0
New Brunswick 0 0 0 0 0 0 0 0 0 0                                               0
Nova Scotia 0 0 0 0 0 0 0 0 0 0                                               0
Quebec 0 0 0 0 0 0 0 0 0 0                                               0
Ontario 0 0 0 0 0 0 0 0 3 0                                               3
Manitoba 0 0 0 0 0 0 0 0 0 0                                               0
Saskatchewan 0 0 0 0 0 0 0 0 0 0                                               0
Alberta 0 0 0 0 0 0 0 0 0 0                                               0
British Columbia 0 0 0 0 0 0 0 0 0 0                                               0
Yukon Territory 0 0 0 0 0 0 0 0 0 0                                               0
Northwest Territory 0 0 0 0 0 0 0 0 0 0                                               0
Nunavut 0 0 0 0 0 0 0 0 0 0                                               0
Total 0 0 0 0 0 0 0 0 3 0                                                

Figure 5: Percentage of dead birds tested positive for West Nile virus by report week in 2012, 2015, 2016, 2017 and number of dead birds tested positive, by report week, 2017, in CanadaFootnote 2

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Figure 5: Text Equivalent
Table showing Percentage of dead birds tested positive for WNV in Canada, by Report week in 2012, 2015, 2016 and 2017 and number of dead birds tested positive for WNV, by Report week, 2017 season
  Year 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
% Positive 2012 0 0 0 0 0 0 0 0 0 0 33 67 33 67 33 50 67 64 67 33 67 67 55 0 0 0 0 0 0 0 0 0
% Positive 2015 0 0 0 0 0 0 0 100 0 0 0 100 83 60 73 0 25 67 83 57 50 80 67 0 21 0 0 0 0 50 0 0
% Positive 2016 0 0 0 0 0 0 0 0 0 0                                            
# Positive 2016 0 0 0 0 0 0 0 0 0 0                                            
# Positive 2017 0 0 0 0 0 0 0 0 3 0                                            

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