West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - August 14 to August 20, 2016 (Week 33)

West Nile virus

Canada

Humans

During surveillance week 33, ending on August 20, 2016, seven (7) human clinical cases of West Nile virus (WNV) were reported to the Public Health Agency of Canada (PHAC). Of these, four cases were reported in Manitoba, one case in Ontario, one case in Quebec, and one case in Saskatchewan.

As of surveillance week 33, a total of ten (10) human clinical cases have been reported to PHAC: Manitoba (7) [Interlake-Eastern (1), Prairie Mountain (1), Southern (2) and Winnipeg (3)], Ontario (1) [Toronto], Quebec (1) [Capitale-Nationale], and Saskatchewan (1) [Mixed-Grass PrairieFootnote *]. Of these, three cases were classified as West Nile virus Neurological Syndrome (30%), and seven as Unclassified (70%).

Mosquitoes

As of surveillance week 33, 181 (1.84 %) out of 9,814 mosquito pools have tested positive for WNV in Canada: Manitoba (37), Ontario (94), Quebec (10), and Saskatchewan (40).

Birds

As of August 20, 2016, the Canadian Wildlife Health Cooperative has examined a total of 36 dead birds for WNV: Ontario (32), Quebec (2), and Saskatchewan (2), of which 2 dead birds have tested positive for WNV in Ontario. One of the birds that tested positive for WNV was a Red- tailed Hawk (Toronto) and the other an American Crow (Sarnia). In addition, the Québec Ministry of Agriculture, Fisheries and Food, and the Québec Centre for Wildlife Health have reported one bird, a Merlin that tested positive for WNV.

Domestic Animals

As of Aug 20, 2016, the Canadian Food Inspection Agency has reported a total of 2 horses that have tested positive for WNV: Manitoba (2) [Brandon (1) and Winnipeg (1)].

United States and U.S. territories

As of August 20, 2016, the Centers for Disease Control and Prevention have reported 213 human clinical cases of West Nile virus disease from 28 states in the USA, including Idaho (1), Minnesota (2), Michigan (1), North Dakota (4), Vermont (2) and Wisconsin (1). Of these, 101 (47%) were diagnosed as neuroinvasive disease cases and 112 (53% ) as non- neuroinvasive disease cases. Five fatal cases have been reported. In addition, 55 presumptive viremic blood donors have been identified.

Detailed information can be accessed via the CDC web site: CDC web site.

Europe and Neighbouring Countries

As of August 20, 2016, 22 human cases of WNV have been reported in the European Union and 43 cases have been reported in the neighbouring countries.

Detailed information can be accessed via the ECDC web site: ECDC web site.

FIGURE 1: Geographic distribution of Human Clinical cases of WNV in Canada, as of August 20, 2016

Figure 1 - Text Description

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

As of surveillance week 33, ending August 20, 2016, a total of ten human clinical cases of WNV have been reported in Canada: Manitoba (7), Ontario (1), Quebec (1) and Saskatchewan (1).

FIGURE 2: WNV Human Clinical cases and Asymptomatic Infections, by Province/ Territory and by Report week, as of August 20, 2016

Figure 2 - Text Description
WNV Human Clinical cases and Asymptomatic Infections, by Province/ Territory and by Report week, as of August 13, 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
Prince Edward Island 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
Nova Scotia 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                                   1
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1                                   1
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 4                                   7
Saskatchewan 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
British Columbia 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
Northwest Territory 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
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 7                                   10

FIGURE 3: WNV Human Clinical cases and Asymptomatic Infections by Report week for selected years, in Canada


Figure 3 - Text Description
WNV Human Clinical cases and Asymptomatic Infections in Canada, by Report week for selected years
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 0 0 0 0 0 0 0 1 2 7                                   10
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 33: August 14 to August 20, 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 1 0 0 1 0 0
Ontario 1 0 0 1 0 0
Manitoba 0 0 4 4 0 0
Saskatchewan 0 0 1 1 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 0 5 7 0 0
  Year to date: January 1 to August 20, 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 1 0 0 1 0 0
Ontario 1 0 0 1 0 0
Manitoba 1 0 6 7 0 0
Saskatchewan 0 0 1 1 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 3 0 7 10 0 0
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 and number of positive mosquito pools by Province/Territory, 2016 season
Province Year to date: January 1 to August 20, 2016Table 2 Footnote *
Number of positive mosquito pools Number of mosquito pools tested Percentage of positive mosquito pools (%)
Quebec 10 477 2.10
Ontario 94 7606 1.24
Manitoba 37 1250 2.96
Saskatchewan 40 481 8.32
Total 181 9814 1.84
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 _          
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 _          
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 _          
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 _          
Quebec 0 0 0 0 0 0 0 0 0 0 2/59 0/67 0/65 2/78 4/69 2/79 0/60          
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          
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          
Saskatchewan 0 0 0 0 0 0 0/1 0/9 0/8 0/14 1/26 0/37 0/31 3/62 10/67 16/106 10/117          
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 _          
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 _          
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 _          
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 _          
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 _          
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 61/1202          
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

FIGURE 4: Reported number of dead birds tested positive for WNV by Province/ Territory and by Report week, 2016 season in Canada

Figure 4 - Text Description
Reported number of dead birds tested positive for WNV in Canada, by Province/ Territory and by Report week, 2016 season
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
Prince Edward Island 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
Nova Scotia 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                                   1
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2                                   2
Manitoba 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
Alberta 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
Yukon Territory 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
Nunavut 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 0 3                                   3

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 - Text Description
Percentage of dead birds tested positive for WNV in Canada, by Report week in 2012, 2015 and 2016, and number of dead birds tested positive for WNV, by Report week, 2016 season
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 0 100                              
# Positive 2016 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3                              
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