West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - August 3 to August 9, 2014 (Report Week 32)

Summary

Canada

Humans: As of surveillance week 32 (August 3 to August 9, 2014), no confirmed human cases of West Nile Virus (West Nile Virus) were reported to the Public Health Agency of Canada (the Agency).

Mosquitoes: Since the start of the 2014 West Nile Virus season, a reported 26 mosquito pools tested positive for West Nile Virus in Canada: 10 in Quebec [Montreal (8) Laval (1) and Montérégie]; nine in Ontario [Halton Region (1), Peel Region (4), Lambton Health Unit (1), Toronto Public Health (1) and Middlesex-London (2)] and seven in Manitoba [Interlake-Eastern Health Region (4), Winnipeg Health Region (1) and Southern Health Region (2)].

Dead Birds: During surveillance week 32, the Canadian Wildlife Health Cooperative tested two dead birds for West Nile Virus in Saskatchewan and both are positive for West Nile Virus.

Since the start of the 2014 West Nile Virus season, the Canadian Wildlife Health Cooperative has tested 39 dead birds for West Nile Virus in Canada: Saskatchewan (26), Ontario (10) and Quebec (3). Of these, two (5.1%) are positive for West Nile Virus.

Domestic Animals: Since the start of the 2014 West Nile Virus season, the Canadian Food Inspection Agency reported two horses tested positive for West Nile Virus in Canada: Alberta (1) and Saskatchewan (1).

United States

Since the start of the 2014 West Nile Virus (West Nile Virus) season, 82 human West Nile Virus cases were reported by the Centers for Disease Control and Prevention [Arizona (13), Arkansas (1), California (19), Colorado (5), District of Columbia (1), Georgia (1), Iowa (3), Louisiana (11), Mississippi (5), Missouri (2), Nebraska (5), New York (1), Oklahoma (1), South Dakota (12), Tennessee (1), Texas (1) and Wisconsin (1)]. Of these, 39 (47.6%) were diagnosed as neuroinvasive disease cases and 43 (52.4%) as non-neuroinvasive cases. Four fatal cases were reported. Twenty-eight presumptive viremic blood donors have been identified.

European Union, European Economic Area and Neighbouring Countries

Since the start of the 2014 West Nile Virus (West Nile Virus) season, no human cases have been reported in the European Union/European Economic Area by the European Centre for Disease Prevention and Control. Twenty-five human cases have been reported in neighbouring countries: Bosnia and Herzegovina (13), Russian Federation (7) and Serbia (5).

Figure 1. West Nile Virus clinical cases and asymptomatic infections, by Province/Territory and by report week, 2014 season

* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date.

Table 1: West Nile Virus clinical cases and asymptomatic infections, by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report week of 2014
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                              
Prince Edward Island 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                              
Nova Scotia 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                              
Ontario 0 0 0 0 0 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 0 0 0                              
Saskatchewan 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                              
British Columbia 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                              
Northwest Territory 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                              
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                              
Table 2. West Nile Virus human clinical cases and asymptomatic infections by Province/Territory for the current Report week and year to date, 2014 Season
Provinces and Territories Week 32: August 3 to August 9, 2014
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 infectionsFootnote 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 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 0 0 0 0 0 0
  Year to date: January 1 to August 9, 2014
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 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 0 0 0 0 0 0

Figure 2. West Nile Virus clinical cases and asymptomatic infections by report week for selected years

* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date.

Table 3: West Nile Virus clinical cases and asymptomatic infections by report week for selected years
Years Report week of 2014
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
2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                              
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 4 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
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
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
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 4.1: Reported cumulative number of West Nile Virus positive mosquito pools by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report week of 2014
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                              
Prince Edward Island 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                              
Nova Scotia 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 1 4 9 10                              
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 2 5 9                              
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 7                              
Saskatchewan 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                              
British Columbia 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                              
Northwest Territory 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                              
Total 0 0 0 0 0 0 0 0 0 0 0 0 1 6 21 26                              
Table 4.2: Detailed mosquito pools tested and positive mosquito pools by Province/Territory, 2014 season
Year to date: January 1 to August 9, 2014
Number of mosquito
pools tested
Number of positive
mosquito pools
Percentage of positive
mosquito pools (%)
Newfoundland and Labrador 0 0 0
Prince Edward Island 0 0 0
New Brunswick 0 0 0
Nova Scotia 0 0 0
Quebec 6,329 10 0.2
Ontario 3,138 9 0.3
Manitoba 734 7 1.0
Saskatchewan 273 0 0
Alberta 0 0 0
British Columbia 101 0 0
Yukon Territory 0 0 0
Northwest Territory 0 0 0
Nunavut 0 0 0
Total 10,575 26 0.2

Figure 3. Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2014 season *

* Data from the Canadian Wildlife Health Cooperative

Table 5: Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report week of 2014
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 Total
Newfoundland and Labrador 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
New Brunswick 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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                               0
Ontario 0 0 0 0 0 0 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 0 0 0                               0
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2                               2
Alberta 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
Yukon Territory 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
Nunavut 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                               2

Figure 4. Percentage of dead birds testing positive for West Nile Virus in the 2014 season by report week, as compared to the 2003, 2012 and 2013 seasons

Table 6: Percentage of dead birds testing positive for West Nile Virus in the 2014 season by report week, as compared to the 2003, 2012 and 2013 seasons
  Report week of 2014
17 18 19 20 21 22 23 24 26 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
Numbers positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2                              
Numbers tested 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 34 3 2                              
Percentage positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100                              
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 6 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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