West Nile Virus, National Surveillance Report - November 10 to November 23, 2013 (Report Week 46 & 47)

Posted 2013-12-09

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Summary

Canada

Humans: During weeks 46-47, the Public Health Agency of Canada (the Agency) was informed of two (2) additional cases of West Nile virus (WNv): Manitoba (1) and British Columbia (1). As of November 23 (week 47), a total of one hundred and ten clinical cases and three (3) asymptomatic infections with WNv have been reported to the Agency: twenty-nine in Québec; fifty-three in Ontario; three (3) in Manitoba; six (6) in Saskatchewan, twenty-one in Alberta, and one (1) in British Columbia. Of the 110 clinical cases, 40 (36%) were diagnosed as WNv neurological syndrome; 46 (42%) as WNv non-neurological syndrome; and 24 (22%) as unclassified. Four (4) fatalities (3.6%) associated with West Nile virus have been reported.

Mosquitoes: To date (Week 47), a total of 13, 458 mosquito pools have been tested for WNv in Canada: Québec (2,530); Ontario (8,642); Manitoba (1088); Saskatchewan (909); and British Columbia (289). Of these, 318 (2.4%) positive mosquito pools were reported: Québec (60); Ontario (198); Saskatchewan (40); Manitoba (19); and British Columbia (1).

Dead Birds: A total of 187 dead birds have been tested for WNv by the Canadian Cooperative Wildlife Health Centre (CCWHC) and provinces. Of these, 89 positives were reported: Québec (38); Ontario (36); Manitoba (2); Saskatchewan (11); Alberta (1); and British Columbia (1). In addition, two birds were reported from an Ontario zoo, one domestic Ross goose was reported from MAPAQ (Ministère de l'Agriculture, des pêcherie et de l'Alimentation du Québec).

Domestic Animals: West Nile virus: A total of fifty-seven animals positive for WNv have been reported by the Canadian Food Inspection Agency and provinces: Québec (8); Ontario (15); Manitoba (3); Saskatchewan (17); Alberta (13); and British Columbia (1).

Eastern Equine Encephalitis:
A total of two horses have been tested positive for Eastern Equine Encephalitis in 2013: one in Québec and another in Ontario.

National WNv surveillance data and maps can be found on the PHAC web site.

United States

As of week 47, 2,271 human cases of WNv have been reported by the Centers for Disease Control and Prevention in the United States. Of these, 1140 (50%) were diagnosed as neuroinvasive disease, and 1131 (50%) as non-neuroinvasive. One hundred fatal cases (4%) were reported. Four hundred and three cases of presumptive viremic blood donors were reported.

Detailed information can be accessed via the CDC web site.

Europe and Neighbouring countries

A total of 783 human cases of WNv have been reported by the European Centre for Disease Prevention and Control. Of these, two hundred and twenty-six human cases have been reported in the European Union and the European Economic Area: Croatia (16); Greece (86), Hungary (31), Italy (69); and Romania (24). Five hundred and fifty-seven human cases have been reported in neighbouring countries: Bosnia and Herzegovina (3), the Former Yugoslav Republic of Macedonia one (1); Montenegro (4); Serbia (302); the Russian Federation (177); Ukraine (1); Israel (63); and Tunisia (6).

Detailed information can be accessed via the ECDC web site.

Figure 1. WNv clinical cases and asymptomatic infections, by Province / Territory and
by report week, 2013 season

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* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date
Text Equivalent - Figure 1 WNv clinical cases and asymptomatic infections, by Province / Territory and by report week, 2013 season
WNv clinical cases and asymptomatic infections, by Province / Territory and by report week, 2013 season
  Report Weeks of 2013
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
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
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
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
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
Quebec 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 8 3 4 2 3 1 1 1 0 0 0 1 0 0 0
Ontario 0 0 0 0 0 1 1 0 0 0 1 2 1 5 4 5 5 2 2 7 3 5 0 5 1 0 3 0 0 0 0
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 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 1 3 1 0 1 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 3 5 4 2 5 2 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 1 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
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
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
Total 1 0 0 0 0 1 1 0 0 0 1 2 1 5 5 8 17 11 13 13 11 9 1 6 1 0 3 1 0 1 0
Table 1. West Nile virus human clinical cases and asymptomatic infections
by Province / Territory for the current Report Week and year to date, 2013 Season
Provinces and Territories November 10-November 23, 2013 (Week 46 & 47)
West Nile virus Neurological syndrome
# cases
West Nile virus
Non-Neurological syndrome
# cases
Unclassified/
Unspecified
Total clinical
casesTable 1 - Footnote 1
# of travel
related casesTable 1 - Footnote 2
West Nile virus
asymptomatic infectionsTable 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 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 1 1 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 1 0 1 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 0 1 1 2 0 0
  & Year to date: From January 1 to November 23, 2013
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 22 6 0 28 2 1
Ontario 8 21 23 52 1 1
Manitoba 1 1 1 3 0 0
Saskatchewan 4 1 0 5 0 1
Alberta 5 16 0 21 0 0
British Columbia 0 1 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 40 46 24 110 3 3
Footnote 1
1Total 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.
Footnote 2
2Likely related to travel outside the province/territory. These cases are included in either the total clinical cases or West Nile virus asymptomatic infections.
Footnote 3
3Satisfies 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 (NAT), 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 NAT following any positive donor screen test result.

Figure 2. WNv clinical cases and asymptomatic infections by report week,
2013 season compared to previous seasons


* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date
Text Equivalent - Figure 2 WNv clinical cases and asymptomatic infections by report week, 2013 season compared to previous seasons
WNv clinical cases and asymptomatic infections by report week, 2013 season compared to previous seasons
  Report Weeks of 2013
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
2013 1 0 0 0 0 1 1 0 0 0 1 2 1 5 5 8 17 11 13 13 11 9 1 6 1 0 3 1 0 1 0
2012 1 0 0 0 0 0 0 0 0 0 3 5 11 16 27 53 63 57 43 43 45 24 30 14 9 5 1 0 0 0 0
2011 0 0 0 0 1 0 1 0 2 0 0 0 0 0 1 8 3 8 16 11 5 13 6 3 3 2 0 0 0 0 0
2010 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 1 0 0 0 0 0 0 0 0 0 0 0
2009 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 0 2 1 1 0 0 2 0 0 1 0 0 0 0
2008 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 1 5 6 2 11 8 1 1 0 1 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
2006 0 0 0 0 0 0 0 0 0 0 2 1 1 4 10 11 15 27 22 16 13 1 2 2 0 0 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
2004 0 0 0 0 0 0 0 0 0 1 0 0 0 1 2 6 4 2 3 2 1 1 1 0 0 1 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
Table 2: Reported cumulative number of West Nile virus positive mosquito pools
by Province/Territory and by report week, 2013 seasonTable 2 - Footnote *
Provinces and
Territories
Report weeks of 2013
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
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
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
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
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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 2 3 5 11 23 36 36 40 47 59 60 60 60 60 60 60 60 60 60
Ontario 0 0 0 0 0 0 0 0 0 2 2 4 12 22 41 65 89 131 155 179 190 194 196 198 198 198 198 198 198 198 198
Manitoba 0 0 0 0 0 0 0 0 0 0 0 1 1 7 10 16 16 16 17 17 19 19 19 19 19 19 19 19 19 19 19
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 1 1 3 3 18 29 29 36 40 40 40 40 40 40 40 40 40 40 40 40
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
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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
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
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
Total 0 0 0 0 0 0 0 0 0 2 2 6 16 36 62 111 147 201 245 277 297 313 316 318 318 318 318 318 318 318 318
Footnote *
*Detailed West Nile virus mosquito surveillance data can be accessed through Provincial/ Territorial websites

Figure 3. Reported number of dead birds testing positive for WNv by Province / Territory
and by report week, 2013 season

Text Equivalent - Figure 3 Reported number of dead birds testing positive for WNv by Province / Territory and by report week, 2013 season
Reported number of dead birds testing positive for WNv by Province / Territory and by report week, 2013 season
  Report Weeks of 2013
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
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
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
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
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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 2 4 5 9 6 4 2 0 0 0 0 0 0 0 0 0
Ontario 0 0 0 0 0 0 0 0 0 1 0 0 2 0 8 6 2 0 8 2 2 2 1 0 0 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 3 1 2 1 0 1 0 0 0 2 1 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 1 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 1 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
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
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
Total 0 0 0 0 0 0 0 0 0 1 0 0 5 2 13 9 6 6 18 9 6 6 2 0 1 0 0 0 0 0 0

Figure 4. Percentage of dead birds testing positive for WNv in the 2013 season
by report week, as compared to the 2003 and 2012 seasons

Text Equivalent - Figure 4 Percentage of dead birds testing positive for WNv in the 2013 season by report week, as compared to the 2003 and 2012 seasons
Percentage of dead birds testing positive for WNv in the 2013 season by report week, as compared to the 2003 and 2012 seasons
  Report Weeks of 2013
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
Numbers positive 2013 0 0 0 0 0 0 0 0 0 1 0 0 5 2 13 9 6 6 18 9 6 6 2 0 1 0 0 0 0 0 0
Numbers tested 2013 0 0 0 1 0 0 0 2 2 5 8 5 9 10 29 19 16 16 24 13 9 10 3 3 2 0 0 0 0 0 0
Percentage positive 2013 0 0 0 0 0 0 0 0 0 20 0 0 56 20 45 47 38 38 75 69 67 60 67 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
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
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