West Nile Virus and Other Mosquito-borne Disease National Surveillance Report
2016 - Final - Summary West Nile Virus in Canada
Humans
During the 2016 West Nile virus (WNV) season, seven provinces (Alberta, Manitoba, Ontario, Quebec, Saskatchewan, New Brunswick and Prince Edward Island) reported West Nile virus activity to the Public Health Agency of Canada. 104 human clinical cases (both confirmed cases and probable cases) were reported in Canada: Alberta (5), Manitoba (23), Ontario (44), Quebec (30), New Brunswick (1), and Prince Edward Island (1). Of these, sixty (58%) were classified as West Nile virus Neurological Syndrome, thirty-seven (35%) as West Nile virus Non-Neurological Syndrome, and seven (7%) as unclassified. Nine fatalities were reported. In addition, two asymptomatic infections were reported: one in Manitoba, and the other in Saskatchewan.
Mosquitoes
345 (2.28 %) out of 15,124 mosquito pools tested positive for West Nile virus in the following provinces: Saskatchewan 67 (11.22%), Manitoba 39 (2.80 %), Ontario 211 (1.73 %), and Quebec 28 (2.99%).
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Wild Birds
The Canadian Wildlife Health Cooperative and the Québec Centre for Wild Animal Health examined a total of 141 dead birds for WNV in 2016, of which 37 (26%) dead birds were positive for West Nile virus: British Columbia (2), Saskatchewan (4), Ontario (20), and Quebec (11).
The positive bird species included Red-tailed hawk (29%), American crow (24%), Sharp -shinned hawk (16%), Merlin (8%), Goshawk (8%), Black-billed Magpie (3%), Blue Jay (3%), Burrowing Owl (3%), Cooper’s Hawk (3%), and Great horned owl (3%).
Domestic Animals
Forty-six horses with WNV infection were reported to the Canadian Food Inspection Agency by various provincial/private animal health laboratories. In addition, the Quebec Ministry of Agriculture, Fisheries and Food, reported two horses positive for West Nile virus.
Ten horses were reported in British Columbia [Langley(1), Nelson (1), Cranbrook (4) and Creston (4)], seven in Alberta [ Lethbridge (3), Taber (1), Brooks (1), Dalemead (1), Strathmore (1)], thirteen in Manitoba [Minnedosa (1), Steinbach (2), Winnipeg (1), Beauséjour (1), Hartney (3), Stonewall (1), Virden (2), Glenboro (1), Elm Creek (1) ], thirteen in Saskatchewan [ Maple Creek (3), Moose Jaw (2), Ogema (1), Swift Current (2), Redvers (1), Assiniboia (1), Melfort (1), Saskatoon (1), Simmie (1) ], two in Ontario [ Mississauga (1), Denfield (1)], and three in Quebec [ Saint-Hyacinthe (1), Lanaudiere (1), Mauricie-Centre du Quebec (1) ].
Eastern Equine Encephalitis Virus in Canada
Humans
In the summer 2016, the first human case of mosquito-borne Eastern Equine Encephalitis (EEE) virus was reported in Canada. The individual was a resident of Ontario and has fully recovered.
Domestic Animals
Two horses tested positive for Eastern Equine Encephalitis virus in Quebec and were reported by the Canadian Food Inspection Agency through various private animal health laboratories.
California Serogroup Viruses in Canada
In 2016, 24 human cases of laboratory confirmed cases/exposures of California serogroup virus were diagnosed by the National Microbiology Laboratory in the following provinces: Alberta (3), Manitoba (3), Ontario (2), Quebec (11), New Brunswick (2), and Nova Scotia (3). Of these cases, 14 were further classified as Jamestown Canyon virus, 3 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.
Figure 1: Geographic distribution of West Nile virus in humans (clinical cases) and horses in Canada, 2016
Figure 2: West Nile virus clinical cases and asymptomatic infections by Province/ Territory, Canada, 2016
* 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
Province | Episode weeks/ month, 2016 | |||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Apr | May | June | July | Aug | Sept | Oct | Nov | Dec | ||||||||||||||||||||||||||
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 | |
Prince Edward Island | 0 | 0 | 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 |
New Brunswick | 0 | 0 | 0 | 1 | 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 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | 3 | 1 | 3 | 11 | 4 | 0 | 0 | 2 | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
Ontario | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 3 | 5 | 6 | 10 | 6 | 6 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Manitoba | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 7 | 4 | 2 | 2 | 2 | 1 | 1 | 1 | 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 | 0 | 1 | 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 | 1 | 0 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 5 | 5 | 14 | 11 | 16 | 12 | 9 | 6 | 15 | 5 | 0 | 0 | 3 | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
|
Province | West Nile virus neurological syndrome | West Nile virus non-neurological syndrome | Unclassified/ unspecified | Total clinical casesFootnote 1 | Number of travel-related casesFootnote 2 | West Nile virus asymptomatic infectionFootnote 3 |
---|---|---|---|---|---|---|
Prince Edward Island | 0 | 1 | 0 | 1 | 1 | 0 |
New Brunswick | 0 | 1 | 0 | 1 | 1 | 0 |
Quebec | 18Footnote * | 12 | 0 | 30Footnote * | 0 | 0 |
Ontario | 29 | 8 | 7 | 44 | 2 | 0 |
Manitoba | 12 | 11 | 0 | 23 | 0 | 1 |
Saskatchewan | 0 | 0 | 0 | 0 | 0 | 1 |
Alberta | 1 | 4 | 0 | 5 | 1 | 0 |
Total | 60 | 37 | 7 | 104 | 5 | 2 |
|
Figure 3: West Nile virus clinical cases and asymptomatic infections by report week for selected years
* 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.
Year | Episode weeks/month, 2016 | |||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Apr | May | June | July | Aug | Sept | Oct | Nov | Dec | ||||||||||||||||||||||||||
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 | |
2016 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 5 | 5 | 14 | 11 | 16 | 12 | 9 | 6 | 15 | 5 | 0 | 0 | 3 | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
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 |
2014 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 4* | 3 | 5 | 6 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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 |
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 |
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 |
2005 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 4 | 11 | 28 | 28 | 38 | 45 | 27 | 15 | 7 | 12 | 3 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
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 |
Province | 2016 West Nile virus seasonFootnote * | ||
---|---|---|---|
Number of positive mosquito pools | Number of mosquito pools tested | Percentage of positive mosquito pools (%) | |
Quebec | 28 | 935 | 2.99 |
Ontario | 211 | 12198 | 1.73 |
Manitoba | 39 | 1394 | 2.80 |
Saskatchewan | 67 | 597 | 11.22 |
Total | 345 | 15124 | 2.28 |
|
Province | Report Weeks of 2016 | ||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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 | |
Quebec | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 3 | 1 | 2 | 2 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
Ontario | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 0 | 0 | 1 | 2 | 0 | 4 | 0 | 8 | 0 | 0 | 0 |
Saskatchewan | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
British Columbia | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 7 | 1 | 4 | 3 | 3 | 1 | 5 | 0 | 8 | 0 | 0 | 0 |
|
Figure 4: Numbers and Percentages of dead birds tested positive for West Nile virus in the 2016 season by report week, as compared to percentages in 2003, 2012 and 2015 seasons
Year | Report Weeks | |||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 to 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 | ||
Numbers positive | 2016 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 7 | 1 | 4 | 3 | 3 | 1 | 5 | 0 | 8 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Numbers tested | 2016 | 4 | 1 | 0 | 0 | 1 | 4 | 3 | 1 | 3 | 1 | 2 | 5 | 9 | 4 | 2 | 6 | 6 | 30 | 4 | 5 | 7 | 7 | 5 | 14 | 3 | 10 | 1 | 1 | 1 | 0 | 0 | 0 | 1 |
Percentage positive | 2016 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 33 | 50 | 23 | 25 | 80 | 43 | 43 | 20 | 36 | 0 | 80 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Percentage 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 | 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 |
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 |
Figure 5: Geographic distribution of Eastern Equine Encephalitis in horses in Canada, 2016
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