West Nile virus and other mosquito-borne disease national surveillance report 2015

2015 - Final - Summary

West Nile Virus in Canada

Humans: During the 2015 West Nile virus season, three provinces: Manitoba (3 health regions), Ontario (15 health regions) and Quebec (8 health regions) reported human cases of West Nile virus to the Public Health Agency of Canada (Figure 1).

A total of 80 human clinical cases were reported in Canada: Manitoba (5), Ontario (33), and Quebec (42). Of these, forty-seven (59%) were classified as West Nile virus Neurological Syndrome, twenty-six (32%) as West Nile virus Non-Neurological Syndrome, and seven (9%) unclassified. No fatalities were reported.

In addition, four (4) asymptomatic infections have been reported: one in Ontario [Toronto], and three in Quebec [Laval (1) and Montérégie (2)] (Table 2).

Mosquitoes: A total of 173 (0.86%) out of 20,046 mosquito pools tested positive for West Nile virus in the following provinces: Saskatchewan 16 (3.04%), Manitoba 30 (1.61%), Ontario 94 (0.59%), and Quebec 33 (1. 89%) (Table 4). Mosquito species positive for WNV were identified as Culex tarsalis, Culex pipiens and Culex restuans.

Wild Birds: The Canadian Wildlife Health Cooperative and the Québec Centre for Wild Animal Health examined a total of 104 dead birds for West Nile virus in 2015, of which 50 (48%) have tested positive for West Nile virus: Saskatchewan (1), Ontario (23), and Quebec (26).

The positive birds were identified as American crow (36%), Great horned owl (18%), Red-tailed hawk (10%), Merlin (8%), Sharp -shinned hawk (8%), Snowy owl (4%), Mallard (4%), Bald eagle (2%), Common Grackle (2%), Gyrfalcon (2%), Northern Harrier (2%), Northern Saw-Whet Owl (2%), and Double-crested cormorant (2%).

Domestic Animals: The Canadian Food Inspection Agency (CFIA) and the Québec Ministry of Agriculture, Fisheries and Food, reported a total of 19 horses tested positive for West Nile virus: Alberta (8), Saskatchewan (5), Manitoba (2), Ontario (3), and Quebec (1). Cases reported to the CFIA were collected through provincial and private animal health laboratories.

California Serogroup Viruses in Canada

In 2015, 40 human cases of laboratory confirmed cases/exposures of California serogroup virus were diagnosed by the National Microbiology Laboratory in the following provinces: Alberta (6), Saskatchewan (2), Manitoba (2), Ontario (4), Quebec (16), New Brunswick (5), and Nova Scotia (5). Of these cases, 30 were further classified as Jamestown Canyon virus, seven as Snowshoe hare virus, and the rest as unknown. Most of the samples were initially collected for testing West Nile virus, and further assayed for non-West Nile virus mosquito-borne agents.

Eastern Equine Encephalitis in Canada

Humans

No human cases of Eastern Equine Encephalitis were reported in Canada.

Domestic Animals

A total of nine horses of Eastern Equine Encephalitis virus were reported in the following three provinces: Ontario (5), Quebec (1) and Nova Scotia (3) (Figure 5). These cases were reported to the Canadian Food Inspection Agency  through a variety of provincial and private animal health laboratories.

Figure 1: Geographic distribution of reported human clinical cases of West Nile virus infection in Canada, 2015

text equivalent below

Figure 1: Text equivalent

Map showing geographic distribution of West Nile virus in humans (clinical cases) in Canada, 2015.

During the 2015 West Nile virus season, a total of 80 West Nile virus human clinical cases were reported in Canada: Manitoba (5), Ontario (33), and Quebec (42).

Figure 2: West Nile virus clinical cases and asymptomatic infections by Province/ Territory, Canada, 2015

text equivalent below in Table 1

Table 1: West Nile virus human clinical cases and asymptomatic infections, by Province/Territory and by report week, 2015 seasonTable 1 Footnote *
  Report Weeks of 2015 Total
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
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 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 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 2 2 2 9 9 7 6 2 3 0 0 0 0 0 0 0 0 45
Ontario 1 0 0 0 0 1 0 1 2 1 0 0 1 0 3 2 6 4 3 2 3 1 1 2 0 0 0 0 0 0 0 0 0 0 34
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 5
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Total 1 0 0 0 0 1 0 1 2 1 0 0 1 1 3 4 7 6 6 5 13 11 8 8 2 3 0 0 0 0 0 0 0 0 84

Table 1 Footnotes

Table 1 Footnote *

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.

Return to table 1 footnote * referrer

Table 2: West Nile virus human clinical cases and asymptomatic infections by Province/Territory for the 2015 season
  West Nile virus neurological syndrome West Nile virus non-neurological syndrome Unclassified/ unspecified Total clinical casesTable 2 Footnote 1 Number of travel-related casesTable 2 Footnote 2 West Nile virus asymptomatic infectionTable 2 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 32 10 0 42 2 3
Ontario 14 12Table 2 Footnote * 7 33Table 2 Footnote * 0 1
Manitoba 1 4 0 5 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 47 26Table 2 Footnote * 7 80Table 2 Footnote * 2 4

Table 2 Footnotes

Table 2 Footnote 1

Total clinical case 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 2 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 2 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

Footnote *

One of these cases was likely exposed prior to the 2015 West Nile virus season.

Return to table 1 footnote * referrer

Figure 3: West Nile virus clinical cases and asymptomatic infections by report week for selected years

text equivalent below in Table 3

* 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.

Table 3: West Nile virus clinical cases and asymptomatic infections by report week for selected years
  Report Week Total
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
2015 1 0 0 0 0 1 0 1 2 1 0 0 1 1 3 4 7 6 6 5 13 11 8 8 2 3 0 0 0 0 0 0 0 0 84
2014 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 4Table 3 Footnote * 3 5 6 1 1 0 0 1 0 0 0 0 0 0 0 0 0 22
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
2003 0 0 0 0 0 0 0 0 0 1 1 1 5 11 9 27 66 249 323 324 178 107 82 37 14 8 4 3 0 0 0 0 0 0 1450

Table 3 Footnotes

Table 3 Footnote *

One of these cases was likely exposed prior to the 2014 West Nile virus season.

Return to table 3 footnote * referrer

Table 4: Number of mosquito pools tested for West Nile virus and number of positive mosquito pools by Province/Territory, 2015 season
Province Year to date: January 1 to Dec 19, 2015Table 4 Footnote *
Number of positive mosquito pools Number of mosquito pools tested Percentage of positive mosquito pools (%)
Quebec 33 1743 1.89
Ontario 94 15918 0.59
Manitoba 30 1858 1.61
Saskatchewan 16 527 3.04
Total 173 20046 0.86

Table 4 Footnotes

Table 4 Footnote *

In 2015, mosquito surveillance was conducted by the following provinces only: Quebec, Ontario, Manitoba and Saskatchewan

Return to table 4 footnote * referrer

Table 5: Reported number of dead birds tested positive for West Nile virus by Province/Territory and by report week, 2015 seasonTable 5 Footnote *
  Report Weeks of 2015 Total
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
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 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 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Quebec 0 0 0 0 0 0 0 0 0 1 1 1 0 2 0 0 0 5 7 3 2 0 3 0 0 0 1 0 0 0 0 0 0 0 26
Ontario 0 0 0 0 0 0 1 0 0 0 0 2 3 1 1 1 0 1 0 3 3 5 0 0 0 0 1 0 0 1 0 0 0 0 23
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  0 0 0 0 0 0
Total 0 0 0 0 0 0 1 0 0 1 1 3 3 3 1 2 0 6 7 6 5 5 3 0 0 0 2 0 0 1 0 0 0 0 50

Table 5 Footnotes

Table 5 Footnote 1

Data from the Canadian Wildlife Health Cooperative and the Québec Centre for Wild Animal Health

Return to table 5 footnote * referrer

Figure 4: Percentage of dead birds tested positive for West Nile virus in the 2015 season by report week, as compared to the 2003, 2012 and 2014 seasons

text equivalent below in Table 6

Table 6: Percentage of dead birds tested positive for West Nile Virus in the 2015 season by report week, as compared to the 2003, 2012 and 2014 seasons
  Report Weeks
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
Numbers positive 2015 0 0 0 0 0 0 1 0 0 1 1 3 3 3 1 2 0 6 7 6 5 5 3 0 0 0 2 0 0 1 0 0 0 0
Numbers tested 2015 0 0 0 0 0 1 1 1 0 1 4 8 9 7 3 9 5 6 10 11 5 6 6 4 2 0 3 1 0 1 0 0 0 0
Percentage positive 2015 0 0 0 0 0 0 100 0 0 100 25 37 33 43 33 22 0 100 70 54 100 83 50 0 0 0 67 0 0 100 0 0 0 0
Numbers positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 4 0 3 3 0 1 0 1 0 0 0 0 0 0 0 0
Numbers tested 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 43Table 6 Footnote * 10 13 10 7 13 6 11 4 1 5 3 2 0 0 1 0 0 1 0 0
Percentage positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 20 29 31 0 27 75 0 20 0 50 0 0 0 0 0 0
Percentage 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 0 0
Percentage positive 2003 0 0 1 0 1 1 1 1 1 3 3 6 7 10 17 21 38 35 43 46 45 45 58 29 20 15 8 0 0 0 0 0 0 0

Table 6 Footnotes

Table 6 Footnote *

Data became available during Week 30; this is a cumulative number of dead birds tested from Week 1 to Week 30.

Return to table 6 footnote * referrer

Figure 5: Geographic distribution of Eastern Equine Encephalitis in horses in Canada, 2015

text equivalent below

Figure 5: Text equivalent

Map showing geographic distribution of Eastern Equine Encephalitis in horses during the West Nile virus season in Canada, 2015.

During the 2015 West Nile virus season, a total of nine horses with Eastern Equine Encephalitis virus were reported in Canada: Ontario (5), Quebec (1) and Nova Scotia (3)

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: