West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - August 16 to August 22, 2015 (Report Week 33)

Summary

West Nile Virus in Canada

Humans: During surveillance week 33, ending on Aug 22, 2015, two (2) human cases of West Nile virus were reported to the Public Health Agency of Canada (the Agency). Of them, one case was reported in Ontario (Toronto) and one in Quebec (Lanaudière).

As of surveillance week 33, a total of 6 human cases have been reported to the Agency: Ontario (3) and Quebec (3). Of them, one (16.7%) was classified as West Nile virus Neurological syndrome, five (83.3%) as West Nile virus Non-neurological syndrome.  One of the three cases from Quebec was related to travel outside the province.

Mosquitoes: As of surveillance week 33, 94 mosquito pools have tested positive for West Nile virus in Canada: Ontario (48), Manitoba (28) , Saskatchewan (15) and Quebec (3).

Dead Birds: As of surveillance week 33, the Canadian Wildlife Health Cooperative has reported 22 dead birds that tested positive for West Nile virus. Ontario (14) and Quebec (8).

Domestic Animals: As of surveillance week 33, the Canadian Food Inspection Agency reported 5 horses that tested positive for West Nile virus in Canada: Ontario (2), Manitoba (1), Saskatchewan (1) and Alberta (1).

One horse tested positive for Eastern equine encephalitis virus, from Ontario.

West Nile Virus in United States

As of Aug 18, 2015, the Centers for Disease Control and Prevention (CDC) reported 210 human cases of West Nile virus:

Alabama ( 3), Arizona ( 26), Arkansas (5), California (36), Colorado (8 ), Delaware (1 ), District of Columbia (1), Florida (4),Georgia (1), Idaho (4), Iowa (1),Kansas (6), Louisiana ( 8), Maryland (2), Mississippi (11), Montana (1 ), Nebraska (11), New Jersey (3), New Mexico ( 2), New York (1), North Dakota (4 ), Ohio (6 ), Oklahoma (10), Pennsylvania (3 ), South Dakota( 10), Tennessee (2 ), Texas (26), Virginia (1 ), Washington(12) and Wyoming ( 1).

Of these, 126 (60%) were diagnosed as neuroinvasive disease cases, 84 (40%) as non-neuroinvasive disease cases. 5 fatal cases were reported. 75 presumptive viremic blood donors have been identified.

West Nile Fever in the European Union, European Economic Area and Neighbouring Countries

As of Surveillance week 33, the European Centre for Disease Prevention and Control (ECDC)  has reported thirteen cases of West Nile fever in humans in the EU Member States and ten cases in the neighboring countries. During the past week, Italy reported four new cases (including one asymptomatic), from Cremona, Parma and Reggio nell’Emilia (2 cases), three provinces already affected this year. Romania reported one case from the newly affected Sibiu County, an area also affected last year.

Hungary reported its first case of West Nile fever from Fejer County. Israel reported two new cases from already affected districts, Tel Aviv and Central district.  West Nile virus has been detected in mosquitoes in Lipetskaya and Voronezhskaya oblasts, Russia

FIGURE 1: West Nile Virus human clinical cases and asymptomatic infections, by Province/Territory and by report week, 2015 season

Text description below in table 1

TABLE 1: West Nile Virus human clinical cases and asymptomatic infections, by Province/Territory and by report week, 2015 season
  Report Weeks of 2015
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 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 1  1  0  1                                3
Ontario 0 0 0 0 0 0 0 0 0 0 0 1 0 1  0                                3
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 1 0 2  1  0  2                                6
TABLE 2: West Nile Virus human clinical cases and asymptomatic infections by Province/Territory for the current report week and year to date, 2015 season
  Week 33: Aug 16 to Aug 22, 2015
West Nile virus neurological syndrome West Nile virus non-neurological syndrome Unclassified/unspecified Total clinical casesTable 2 Footnote 1 Number of travel-related casesTable 2 Footnote 2 West Nile virus asymptomatic infectionTable 2 Footnote 3

Table 2 Footnotes

Table 2 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 2 footnote 1 referrer

Table 2 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 2 footnote 2 referrer

Table 2 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 2 footnote 3 referrer

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 0 1 0 1 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 1 1 0 2 0 0
  Year to date: January 1 to Aug 22, 2015
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 2 0 3 1 0
Ontario 0 3 0 3 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 1 5 0 6 1 0

FIGURE 2: West Nile Virus clinical cases and asymptomatic infections by report week for selected years

Text description in table 3 below

* 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
  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

Table 3 Footnotes

Footnote *

One of these cases was likely exposed prior to the 2014 West Nile virus season.

Return to table 3 footnote * referrer

2015 0 0 0 0 0 0 0 0 0 0 0 1 0 2 1 0 2                            
2014 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 4Table 3 Footnote * 3 5 6 1 1 0 0 1 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: Number of West Nile Virus mosquito pools tested weekly by Province/Territory - 2015 season Table 4.1 Footnote 1
Province / Territory Report week of 2015
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 Total

Table 4.1 Footnotes

Table 4.1 Footnote 1

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

Return to table 4.1 footnote 1 referrer

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 0 120 127 132 131 129 126 112 125                       1002
Ontario 0 0 0 0 0 180 356 852 886 954 1152 1216 1219 1222 1176 1168 1168                       11549
Manitoba 0 0 0 0 12 4 87 82 44 75 73 132 139 204 275 195 228                       1550
Saskatchewan 0 0 0 0 2 0 3 3 10 13 16 40 47 69 67 80 94                       444
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 14 184 446 937 940 1162 1368 1520 1536 1624 1644 1555 1615                       14545
TABLE 4.2: Number of mosquito pools tested and number of positive mosquito pools by Province/Territory, 2015 season
Province Year to date: January 1 to Aug 22, 2015
Number of positive mosquito pools Number of mosquito pools tested Percentage of positive mosquito pools (%)
Quebec 3 1002 0.30
Ontario 48 11549 0.42
Manitoba 28 1550 1.81
Saskatchewan 15 444 3.38
Total 94 14545 0.65

FIGURE 3: Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2015 season*

Text description in table 5 below

* Data from the Canadian Wildlife Health Cooperative and the Quebec Ministry of Health and Social Services

TABLE 5: Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2015 season Table 5 Footnote *
  Report week of 2015
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

Table 5 Footnotes

Table 5 Footnote *

Data from the Canadian Wildlife Health Cooperative.

Return to table 5 footnote * referrer

Table 5 Footnote 1

Data from the Quebec Ministry of Health and Social Services

Return to table 5 footnote 1 referrer

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 1 1 2 3 0 1Table 5 Footnote 1                             8
Ontario 0 0 0 0 0 0 0 1 0 0 0 0 4 1 8 0 0                             14
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 1 0 0 0 1 5 3 11 0 1                             22

FIGURE 4: Percentage of dead birds testing positive for West Nile Virus in the 2015 season by report week, as compared to the 2003, 2012 and 2014 seasons

Text description in table 6 below

TABLE 6: Percentage of dead birds testing positive for West Nile Virus in the 2015 season by report week, as compared to the 2003, 2012 and 2014 seasons
  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

Table 6 Footnotes

Table 6 Footnote *

Data became available during Week 30; this is a cumulative number of dead birds tested from Week 1 to Week 30.

Return to table 6 footnote * referrer

Numbers positive 2015 0 0 0 0 0 0 0 1 0 0 0 1 5 3 11 0 1                            
Numbers tested 2015 0 0 0 0 0 0 0 1 0 0 1 1 6 5 15 7 4                            
Percentage positive 2015 0 0 0 0 0 0 0 100 0 0 0 100 83 60 73 0 25                            
Numbers positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 4 0 2 3 0 1 0 0 0 0 0 0 0
Numbers tested 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 41Table 6 Footnote * 10 13 9 7 13 6 10 3 1 4 2 1 0 0 0 0 0
Percentage positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 22 29 31 0 20 100 0 25 0 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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