West Nile Virus and Other Mosquito-Borne Diseases National Surveillance Report - October 9 to October 15, 2016 (Week 41)

West Nile virus

Canada

Humans

During surveillance week 41, ending on October 15, 2016, six (6) human clinical cases of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (PHAC). Of these, one case was reported in Manitoba [Southern (1)], four in Ontario [Peel region (1), Toronto (1),Windsor-Essex County (1), York region (1)], and one in Prince Edward Island.

As of surveillance week 41, a total of 89 human clinical cases have been reported to PHAC:  Alberta (4) [Calgary zone (1) and South zone (3)], Manitoba (21) [Interlake-Eastern (3), Northern (1), Prairie Mountain (2), Southern (9) and Winnipeg (6)], Ontario (44) [Ottawa (2),Toronto (20), Niagara (7), York (3), Durham (2), Halton (1), Windsor-Essex County (3), Peel (4) ,Haldimand-Norfolk (1) and Hamilton (1)], Quebec (19) [Capitale-Nationale (1), Laurentides (2)Footnote *, Laval (5), Montérégie (4), Lanaudière (5), Montréal (1) and  Gaspésie - Îles-de-la-Madeleine (1)] and Prince Edward Island (1).  Of these, fifty-six cases (63 %) were classified as West Nile virus Neurological Syndrome, twenty- eight cases (31 %) as West Nile virus Non-Neurological Syndrome, and five cases (6 %) were unclassified. Seven fatal cases have been reported.

In addition, six West Nile virus asymptomatic infections have been reported by three provinces: Saskatchewan (1) [Mixed-Grass prairie Footnote x], Manitoba (1) [Prairie Mountain]  and Ontario (4) [Toronto (3), Windsor-Essex County (1)].

Mosquitoes

As of surveillance week 41, 345 (2.28 %) out of 15124 mosquito pools have tested positive for WNV in Canada: Saskatchewan (67), Manitoba (39), Ontario (211) and Quebec (28).

Birds

As of surveillance week 41,  the Canadian Wildlife Health Cooperative, the Québec Ministry of Agriculture, Fisheries and Food, and the Québec Centre for Wildlife Health have examined a total of 80 dead birds for WNV: British Columbia (2), Alberta (1), Saskatchewan (5), Ontario (57), and Quebec (15), of which 25 (31%) dead birds have tested positive for WNV: British Columbia (2) [Cranbrook], Saskatchewan (2)[Saskatoon (1), Moose Jaw (1)], Ontario (9) [Bradford (1), Hamilton (1), Sarnia (1), Thorold (1), Toronto (1), Tecumseh (1), Burlington (1), Waterloo (1), Elora (1)] and Quebec (12) [Estrie (2), Lanaudière (1), Montérégie (5), Saint-Jean-Baptiste (1), Abitibi-Témiscaminigue (1), Montréal (1), Capitale Nationale (1)]. The positive birds were identified as American Crows (32%), Red- tailed Hawks (20%), Sharp-shinned Hawks (16%), Merlins (8%), Northern Goshawks (8%), Great- horned Owls (4%), Cooper’s hawks(4%), Blue Jays (4%) and Burrowing Owls (4%).

Domestic Animals

As of surveillance week 41, forty-five horses with WNV infection have been reported to the Canadian Food Inspection Agency by various provincial/private animal health laboratories. These are preliminary data under validation: British Columbia (10), Alberta (7), Manitoba (13), Ontario (2) and Saskatchewan (13). In addition, the Quebec Ministry of Agriculture, Fisheries and Food, has reported one horse that tested positive for WNV, in Quebec.

United States and U.S. territories

As of October 11, 2016, the Centers for Disease Control and Prevention have reported a total of 1,264 human clinical cases of West Nile virus disease in 42 states in the US, including the following border states: Washington (9), Idaho (6), Montana (6), New York (11), North Dakota (68), Minnesota (41), Michigan (34), and Vermont (3). Of these, 645 (51%) were classified as neuroinvasive disease and 619 (49%) were classified as non- neuroinvasive disease. Forty-nine fatal cases have been reported. In addition, 193 presumptive viremic blood donors have been identified.

Detailed information can be accessed via the CDC web site.

Europe and Neighbouring Countries

As of October 20, 2016, a total of 198 human cases of WNV have been reported in the European Union and 249 cases have been reported in the neighbouring countries.

Detailed information can be accessed via the ECDC web site.

Eastern equine encephalitis

Canada

Domestic Animals

As of surveillance week 41, two horses with Eastern Equine Encephalitis in Québec, has been reported to the Canadian Food Inspection Agency by a provincial/private animal health laboratory.

Footnote 1

This case was acquired during WNV season in 2015

Return to footnote * referrer

Footnote 2

Sun Country, Regina Qu'Appelle, Five Hills, Cypress, Heartland Health Regions

Return to first footnote x referrer

Figure 1: Geographic distribution of WNV in humans (clinical cases) and horsesFootnote * in Canada, as of October 15, 2016

Map showing geographic distribution of WNV in Humans (clinical cases) and horses in Canada.

Footnote *

These are preliminary data, under validation

Return to footnote * referrer

Figure 1 - Text Description

Map showing geographic distribution of WNV in Humans (clinical cases) and horses in Canada.

As of surveillance week 41 ending October 15, 2016, a total of 89 human clinical cases of WNV have been reported in Canada: Alberta (4), Manitoba (21), Ontario (44), Quebec (19) and Prince Edward Island (1).

Forty-five horses with WNV infection have been reported (preliminary data): British Columbia (10), Alberta (7), Manitoba (13), Ontario (2) and Saskatchewan (13).

Figure 2: WNV human clinical cases and asymptomatic infections by province/ territory and by report week, as of October 15, 2016

 WNV human clinical cases and asymptomatic infections by province/ territory and by report week, as of October 15, 2016

Footnote *

Acquired during WNV season in 2015

*

Figure 2 - Text Description
WNV human clinical cases and asymptomatic infections by province/ territory and by report week, as of October 15, 2016
  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 46 47 48 49 50 Total
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
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                   1
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
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
Quebec 0 0 0 0 0 0 0 1Footnote * 0 0 0 0 0 0 1 0 0 0 2 3 1 2 7 2 0                   19
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 8 15 8 5 1 4                   48
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 4 4 6 0 3 0 0 2 0                   22
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                   1
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0                   4
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
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
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
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
Total 0 0 0 0 0 0 0 1 0 0 0 0 0 0 2 2 6 8 15 11 19 10 12 5 4                   95
Footnote *

Acquired during WNV season in 2015

*

Figure 3: WNV human clinical cases and asymptomatic infections by report week for selected years, in Canada

WNV human clinical cases and asymptomatic infections by report week for selected years, in Canada

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.

*

Figure 3 - Text Description
WNV human clinical cases and asymptomatic infections by report week for selected years, in Canada
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
2016 0 0 0 0 0 0 0 1 0 0 0 0 0 0 2 2 6 8 15 11 19 10 12 5 4                   95
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
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.

*

Table 1: West Nile virus human clinical cases and asymptomatic infections by province/territory for the current report week and year to date, 2016 season
  Week 41: October 9 to October 15, 2016
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
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 1 0 1 1 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 2 1 1 4 0 0
Manitoba 0 1 0 1 0 1
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 2 3 1 6 1 1
  Year to date: January 1 to October 15, 2016
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 1 0 1 1 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 14Footnote * 5 0 19Footnote * 0 0
Ontario 29 10 5 44 3 4
Manitoba 12 9 0 21 2 1
Saskatchewan 0 0 0 0 0 1
Alberta 1 3 0 4 1 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 56 28 5 89 7 6
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 footnote 1 referrer

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 footnote 2 referrer

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 footnote 3 referrer

Footnote *

One of the cases was acquired in 2015.

Return to footnote * referrer

Table 2: Number of mosquito pools tested and number of positive mosquito pools by province/territory, 2016 season
Province Year to date: January 1 to October 15, 2016 Footnote *
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
Footnote *

In 2016, mosquito surveillance is conducted by the following provinces only: Quebec, Ontario, Manitoba and Saskatchewan

Return to footnote * referrer

Table 3: Number of WNV positive mosquito pools/ total number of WNV mosquito pools tested by report week and by province/ territory, 2016 season Footnote
Province / Territory Report week of 2016
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
Newfoundland and Labrador _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Prince Edward Island _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
New Brunswick _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Nova Scotia _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Quebec 0 0 0 0 0 0 2/59 0/67 0/65 2/78 4/69 2/79 6/76 4/67 2/78 1/89 0/79 1/77 0/52 NA NA
Ontario 0/49 0/90 0/190 0/460 0/542 0/562 0/802 1/795 2/688 5/649 20/927 30/947 36/882 42/886 29/906 17/836 19/767 7/706 2/364 1/102 0/25
Manitoba 0/4 0/8 0/3 0/17 0/56 0/58 0/69 0/100 4/113 7/192 5/241 6/246 15/143 1/65 1/42 0/29 0/8 Footnote Footnote Footnote Footnote
Saskatchewan 0 0 0/1 0/9 0/8 0/14 1/26 0/37 0/31 3/62 10/68 16/106 31/144 4/55 2/28 0/6 Footnote Footnote Footnote Footnote Footnote
Alberta _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
British Columbia _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Yukon Territory _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Northwest Territory _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Nunavut _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Total 0/53 0/98 0/194 0/486 0/606 0/634 3/956 1/999 6/897 17/983 39/1305 54/1378 88/1245 51/1073 34/1054 18/960 19/854 8/783 2/416 1/102 0/25
Footnote 1

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

Return to footnote referrer

Footnote 3

Mosquito surveillance has ended.

Return to footnote referrer

Footnote 2

_ These jurisdictions do not maintain regular mosquito surveillance.

Figure 4: Reported number of dead birds tested positive for WNV in Canada, by province/ territory and by report week, 2016 season

Reported number of dead birds tested positive for WNV in Canada, by province/ territory and by report week, 2016 season

Figure 4 - Text Description
Figure 4: Reported number of dead birds tested positive for WNV in Canada, by province/ territory and by report week, 2016 season
Province/Territory 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 46 47 48 49 50 Total
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
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
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
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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 1 4 1 1 1 0                   12
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 0 0 1 2 0 1 0                   9
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
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0                   2
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
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                   2
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
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
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
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 3 3 3 5 3 1 2 0                   25

Figure 5: Percentage of dead birds tested positive for WNV by report week in 2012, 2015 and 2016, and number of dead birds tested positive for WNV, by report week, 2016, in CanadaFootnote

Figure 5: Percentage of dead birds tested positive for WNV by report week in 2012, 2015 and 2016, and number of dead birds tested positive for WNV, by report week, 2016, in Canada

Footnote 1

Not all provinces are conducting dead bird surveillance as part of their own WNV surveillance program. However, WNV positive dead birds may be identified through the National Wildlife Disease Surveillance Program of the Canadian Wildlife Health Cooperative (CWHC)

Return to footnote referrer

Figure 5 - Text Description
Figure 5: Percentage of dead birds tested positive for WNV by report week in 2012, 2015 and 2016, and number of dead birds tested positive for WNV, by report week, 2016, in Canada Footnote
  Report Week
  Years 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 0 0 0 0 0 40 100 20 75 75 71 100 50 100 0              
# Positive 2016 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 3 3 3 5 3 1 2 0              
Footnote 1

Not all provinces are conducting dead bird surveillance as part of their own WNV surveillance program. However, WNV positive dead birds may be identified through the National Wildlife Disease Surveillance Program of the Canadian Wildlife Health Cooperative (CWHC)

Return to footnote referrer

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: