West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - September 18 to September 24, 2016 (Week 38)

West Nile virus

Canada

Humans

During surveillance week 38, ending on September 24, 2016, eleven (11) human clinical cases of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (PHAC). Of these, eight cases have been reported in Ontario [Ottawa (1),Toronto (2), Windsor-Essex County (2), Durham (1), Peel (1), Haldimand-Norfolk (1)] and three cases in Quebec [Montérégie (2), Montréal (1)].

As of surveillance week 38, a total of 69 human clinical cases have been reported to PHAC:  Alberta (4) [Calgary zone (1) and South zone (3)], Manitoba (20) [Interlake-Eastern (3), Northern (1), Prairie Mountain (2), Southern (8) and Winnipeg (6)], Ontario (34) [Ottawa (1),Toronto (17), Niagara (6), York (2), Durham (2), Halton (1), Windsor-Essex County (2), Peel (2) ,Haldimand-Norfolk (1)] and Quebec (11) [Capitale-Nationale (1), Laurentides (1)Footnote *, Laval (3), Montérégie (3), Lanaudière (2), Montréal (1) ]. Of these, thirty-seven cases (54 %) were classified as West Nile virus Neurological Syndrome, nineteen cases (27 %) as West Nile virus Non-Neurological Syndrome, and thirteen cases (19 %) were unclassified. Three fatal cases have been reported.

In addition, five West Nile virus asymptomatic infections have been reported: Saskatchewan (1) [Mixed-Grass prairieFootnote x (1)] and Ontario (4) [Toronto (3), Windsor-Essex County (1)].

Mosquitoes

As of surveillance week 38, 338 (2.32 %) out of 14569 mosquito pools have tested positive for WNV in Canada: Saskatchewan (67), Manitoba (39), Ontario (208) and Quebec (24).

Birds

As of surveillance week 38,  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 66 dead birds for WNV: British Columbia (2), Saskatchewan (3), Ontario (49), and Quebec (12), of which 21 (32%) dead birds have tested positive for WNV: British Columbia (2) [Cranbrook], Sakatchewan (1)[Saskatoon], [Ontario (8) [Bradford (1), Hamilton (1), Sarnia (1), Thorold (1), Toronto (1), Tecumseh (1), Burlington (1), Waterloo (1)] and Quebec (10) [ Estrie (1), Lanaudière (1), Montérégie (5), Saint-Jean-Baptiste (1), Abitibi-Témiscaminigue (1), Montréal (1)]. The positive birds were identified as American Crows (38%), Red- tailed Hawks (24%), Sharp-shinned Hawks (14%), Merlins (9%), Northern Goshawks (5%), Great- horned Owl (5%) and Cooper's hawk (5%).

Domestic Animals

As of surveillance week 38, forty-four 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 (12), 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 September 24, 2016, the Centers for Disease Control and Prevention have reported a total of 986 human clinical cases of West Nile virus disease in the US, including the following border states: Washington (8), Idaho (6), Montana (5), New York (1), North Dakota (11), Minnesota (34), Michigan (32), and Vermont (3). Of these, 505 (51%) were classified as neuroinvasive disease and 481 (49%) were classified as non- neuroinvasive disease.

Detailed information can be accessed via the CDC web site.

Europe and Neighbouring Countries

As of September 24, 2016, a total of 149 human cases of WNV have been reported in the European Union and 205 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 38, one horse with Eastern Equine Encephalitis in Berthierville, Québec, has been reported to the Canadian Food Inspection Agency by a provincial/private animal health laboratory.

Figure 1: Geographic distribution of WNV in humans (clinical cases) and horsesFigure 1 - Footnote * in Canada, as of September 24, 2016

Map of West Nile Virus number of cases

Figure 1 - Footnote *

These are preliminary data, under validation.

Return to Figure 1 - Footnote * referrer

Figure 1 - Text Description

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

As of surveillance week 38, ending September 24, 2016, a total of 69 human clinical cases of WNV have been reported in Canada: Alberta (4), Manitoba (20), Ontario (34) and Quebec (11).

Forty-four horses with WNV infection have been reported (preliminary data): British Columbia (10), Alberta (7), Manitoba (12), Ontario (2) and Saskatchewan (13).

Figure 2: WNV human clinical cases and asymptomatic infections by province/ territory and by report week, as of September 24, 2016

Figure 2

Figure 2 - Text Description
WNV human clinical cases and asymptomatic infections by province/ territory and by report week, as of September 24, 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
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
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
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
Quebec 0 0 0 0 0 0 0 1Figure 2 Footnote * 0 0 0 0 0 0 1 0 0 0 2 2 2 3                         11
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 8 15 8                         38
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 4 4 6 0 3 0                         20
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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                         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
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
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
Nunavut 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 7 15 10 20 11                         74
Figure 2 Footnote *

Acquired during WNV season in 2015

Return to figure 2 footnote * referrer

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

Figure 3

Figure 3 - 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 Figure 3 - Footnote * referrer

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 7 15 10 20 11                         74
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, 2016 season
  Week 38: September 18 to September 24, 2016
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 3 0 0 3 0 0
Ontario 5 2 1 8 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 8 2 1 11 0 0
- Year to date: January 1 to September 24, 2016
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 8Table 1 Footnote * 3 0 11Table 1 Footnote * 0 0
Ontario 22 8 4 34 3 4
Manitoba 6 5 9 20 0 0
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 37 19 13 69 4 5
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 1 Footnote *

One of the cases was acquired in 2015.

Return to table 1 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 September 24, 2016Table 2 Footnote *
Number of positive mosquito pools Number of mosquito pools tested Percentage of positive mosquito pools (%)
Quebec 24 871 2.76
Ontario 208 11707 1.78
Manitoba 39 1394 2.8
Saskatchewan 67 597 11.22
Total 338 14569 2.32
Table 2 Footnote ͌

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

Return to table 2 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 seasonTable 3 Footnote ǂ
Province / Territory Report week of 2016
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
Newfoundland and Labrador Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Prince Edward Island Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
New Brunswick Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Nova Scotia Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Quebec 0 0 0 0 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 0/65
Ontario 0 0/6 0/5 0/12 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
Manitoba 0 0 0 0 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 Table 3 - Footnote *
Saskatchewan 0 0 0 0 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 Table 3 - Footnote * Table 3 - Footnote *
Alberta Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
British Columbia Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Yukon Territory Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Northwest Territory Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Nunavut Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _ Table 3 - Footnote _
Total 0 0/6 0/5 0/12 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 7/771
Table 3 Footnote ǂ

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

Return to table 3 footnote ǂ referrer

Table 3 - Footnote _

These jurisdictions do not maintain regular mosquito surveillance.

Return to first Table 3 - Footnote _ referrer

Table 3 - Footnote *

Mosquito surveillance has ended.

Return to first Table 3 - Footnote * referrer

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

Figure 4

Figure 4 - Text Description
Reported number of dead birds tested positive for WNV by province/ territory and by report week, 2016 season in Canada
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
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
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
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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 1 4 1                         10
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 0 0 1 2                         8
Manitoba 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 0 0 1                         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
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 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
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
Nunavut 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 1 5 4                         21

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 CanadaFigure 5 Footnote

Figure 5

Figure 5 - Footnote ¶

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 Figure 5 - Footnote referrer

Figure 5 - Text Description
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
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
% 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 23 75 100 100 100                    
# Positive 2016 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 3 3 1 5 4                    
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