West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - September 7 to September 13, 2014 (Report Week 37)

Summary

Canada

Humans: During surveillance week 37 (September 7 to September 13, 2014), nine human clinical cases of West Nile virus were reported in Canada: one in Manitoba (Interlake-Eastern Health Region), four in Ontario [Chatham-Kent (1), City of Ottawa (1) and City of Toronto (2)] and four in Quebec [Lanaudière (1), Montérégie (1) and Montreal (2)]. Of these, three (33.3%) are clinically classified as West Nile virus neurological syndrome, three (33.3%) as West Nile virus non-neurological syndrome and three (33.3%) as unclassified/unspecified.

One asymptomatic infection was reported in Quebec: Mauricie and Centre-du-QuébecFootnote 1.

As of surveillance week 37, 15 human clinical cases of West Nile virus have been reported in Canada: three in Manitoba [Interlake-Eastern Health Region (1), Prairie Mountain Health Region (1)Footnote 1 and Winnipeg Health Region (1)], eight in Ontario [Chatham-Kent (1), Lambton County (1), City of Ottawa (2), Simcoe-Muskoka District (1) and City of Toronto (3)] and four in Quebec [Lanaudière (1), Montérégie (1) and Montreal (2)]. Of these, six (40.0%) are clinically classified as West Nile virus neurological syndrome, five (33.3%) as West Nile virus non-neurological syndrome and four (26.7%) as unclassified/unspecified.

Two asymptomatic infections have been reported: one in Ontario (Windsor-Essex County) and one in Quebec (Mauricie and Centre-du-QuébecFootnote 1).

Mosquitoes: As of surveillance week 37, a reported 195 mosquito pools have tested positive for West Nile virus in Canada: 24 in Manitoba [Interlake-Eastern Health Region (7), Prairie Mountain Health Region (1), Southern Health Region (11) and Winnipeg Health Region (5)]; 52 in Ontario [Haliburton-Kawartha-Pine Ridge District (1), Halton Regional (3), City of Hamilton (7), Lambton (1), Middlesex-London (4), Niagara Regional (2), City of Ottawa (3), Peel Regional (19), City of Toronto (9), Windsor-Essex County (1) and York Regional (2)]; 99 in Quebec [Laval (10), Montérégie (36) and Montreal (53)] and 20 in Saskatchewan.

Dead Birds: During surveillance week 37, the Canadian Wildlife Health Cooperative tested six dead birds for West Nile virus in Canada: Quebec (2) and Saskatchewan (4). Two (33.3%) dead birds have tested positive for West Nile virus in Quebec.

As of surveillance week 37, the Canadian Wildlife Health Cooperative tested 99 dead birds for West Nile virus in Canada: Ontario (20), Quebec (16) and Saskatchewan (63). Of these, 11 (11.1%) dead birds have tested positive for West Nile virus in Canada: Ontario (4), Quebec (5) and Saskatchewan (2).

Domestic Animals: As of surveillance week 37, the Canadian Food Inspection Agency reported 10 horses tested positive for West Nile virus in Canada: Alberta (5), Quebec (1) and Saskatchewan (4).

United States

As of September 9, 2014, the Centers for Disease Control and Prevention (CDC) has reported 579 West Nile virus human disease cases:

Arizona (29), Arkansas (2), California (182), Colorado (41), District of Columbia (2), Florida (1), Georgia (6), Idaho (13), Illinois (4), Indiana (2), Iowa (9), Kansas (5), Louisiana (68), Maryland (1), Massachusetts (1), Minnesota (6), Mississippi (24), Missouri (2), Montana (3), Nebraska (28), Nevada (1), New Jersey (2), New York (4), North Dakota (9), Ohio (3), Oklahoma (6), Pennsylvania (2), South Carolina (2), South Dakota (31), Tennessee (3), Texas (70), Utah (1), Virginia (1), Washington (6), Wisconsin (5) and Wyoming (4).

Of these, 320 (55.3%) were diagnosed as neuroinvasive disease cases and 259 (44.7%) as non-neuroinvasive disease cases. Twenty-three fatal cases were reported. One hundred and forty-one presumptive viremic blood donors have been identified.

European Union, European Economic Area and Neighbouring Countries

During surveillance week 37, the European Centre for Disease Prevention and Control (ECDC) reported 17 new human cases of West Nile fever in Europe: Greece (2), Italy (7) and Romania (8). In the neighboring countries, 29 new human cases were reported: Russian Federation (17) and Serbia (12).

As of September 11, 2014, 37 human cases of West Nile fever have been reported in Europe: Austria (1), Greece (13), Italy (8) and Romania (13). In the neighbouring countries, 77 human cases have been reported: Bosnia and Herzegovina (13), Israel (2), Russian Federation (24) and Serbia (38).

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

* 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 clinical cases and asymptomatic infections, by Province/Territory and by report week, 2014 season
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 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
New Brunswick 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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5Footnote *
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 3 4
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2Footnote * 0 0 1
Saskatchewan 0 0 0 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 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
Yukon Territory 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
Nunavut 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 0 0 3Footnote * 1 3 10Footnote *
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 37: September 7 to September 13, 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 3 1 0 4 0 1Footnote **
Ontario 0 2 2 4 1 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 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 3 3 9 1 1Footnote **
Year to date: January 1 to September 13, 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 3 1 0 4 0 1Footnote **
Ontario 2 3 3 8 1 1
Manitoba 1 1Footnote ** 1 3Footnote * 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 6 5Footnote * 4 15Footnote * 1 2Footnote *

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

* 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 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 0 3Footnote * 1 3 10Footnote *
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 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
New Brunswick 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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 1 4 9 10 19 19Footnote ** 39 70 99
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 2 5 9 11 13 30 43 52
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 7 14 19 22 24 24
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 9 19 20 20 20
Alberta 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 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
Northwest Territory 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
Total 0 0 0 0 0 0 0 0 0 0 0 0 1 7 22 28 53 70 111 157 195
Table 4.2: Number of mosquito pools tested and number of positive mosquito pools by Province/Territory, 2014 season
Provinces and
Territories
Year to date: January 1 to September 13, 2014
Number of mosquito
pools tested
Number of positive
mosquito pools
Percentage of positive
mosquito pools (%)
Quebec 9,567 99 1.0
Ontario 12,700 52 0.4
Manitoba 1,505 24 1.6
Saskatchewan 823 20 2.4
British Columbia 236 0 0
Total 24,831 195 0.8

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 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
New Brunswick 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
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 2 5
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 0 0 4
Manitoba 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 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
British Columbia 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
Northwest Territory 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
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 3 0 2 11

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 2 2 3 0 2
Numbers tested 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 39Footnote * 10 13 9 6 12 3 6
Percentage positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 22 33 25 0 33
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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