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ARCHIVED - West Nile Virus, National Surveillance Report - October 21 to October 27, 2012 (Week 43)

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Posted 2012-11-07

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West Nile Virus, National Surveillance Report - October 21 to October 27, 2012 (Week 43) (PDF Version - 293 KB - 8 pages)

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Summary

Canada

Humans: During surveillance week 43, ending on October 27, 2012, nine additional clinical cases caused by West Nile virus were reported to the Public Health Agency of Canada (PHAC). As of week 43, there have been a total of 433 clinical cases and 17 asymptomatic infections reported to PHAC. Of the 433 clinical cases, 139 (32 %) were classified as Neurological Syndrome, 244 (56 %) Non-Neurological Syndrome, and 50 (12%) Unclassified.  Up to week 43, six deaths associated with WNv have been reported.

Mosquitoes: To date, a total of 605 positive mosquito pools have been reported in Canada: 464 in Ontario [Central East (235), Central West (97), Eastern (61), North East (2), South West (62), First Nations Community (7)]; 116 in Manitoba [Interlake-Eastern (13), Southern (48), Western (35), Winnipeg (20)]; 6 in Saskatchewan [Sun Country (3), and Saskatoon (1), Five Hills (1), Cypress (1)] and 19 in Quebec [Laval (3), Bois-des-Filion (3), Gatineau (1), Sainte-Anne-des-Plaines (3), Terrebonne (5), Boisbriand (1), Rosemere (1), and Trois-Rivieres (2)].

Note: Quebec public health authorities have not done mosquito surveillance since 2006, however, entomological surveillance is conducted in some municipalities of the province. As of week 40, Ontario has stopped its mosquito trapping surveillance initiative.

Dead Birds: A total of 118 dead birds have been tested for West Nile virus by the Canadian Cooperative Wildlife Health Centre (CCWHC) in Canada. Of them, 64 were positive for West Nile virus, [33/54 in Ontario, 30/46 in Quebec and 1/11 in Saskatchewan].

Domestic Animals: As of week 43, the Canadian Food Inspection Agency (CFIA) has reported 49 horses testing positive for West Nile virus: [Alberta (5); Manitoba (7); Ontario (8); Quebec (19); and Saskatchewan (10)].

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

United States

As of October 23, 2012 there have been 4,725 human cases of West Nile virus infection reported to the Centers for Disease Control and Prevention in the United States, of which 2,413 (51%) were neuroinvasive and 2,312 (49%) were non-neuroinvasive. 219 deaths have been reported. In addition, 562 West Nile virus presumptive viremic blood donors have been reported.

Detailed information can be accessed via the CDC web siteExternal link.

Europe and Neighbouring Countries

As of October 25, 2012 there have been 775 confirmed human cases of West Nile virus infection reported in Europe and Neighbouring countries [Greece (161), Hungary (8), Italy (45), Romania (14), Algeria (1), Croatia (5), Yugoslav (6), Israel (46), Kosovo (4), Palestine (2), Russian Federation (397), Serbia (64), and Tunisia (22)].

Detailed information can be accessed via the ECDC web siteExternal link.

Figure 1. West Nile virus clinical cases and asymptomatic infections,
by Province / Territory and by report week, 2012 season

Figure 1
Text equivalent for figure 1
WNV Human Clinical Cases and Asymptomatic Infections, by Province/Territory, by Report week, Canada, 2011

Table 1. West Nile virus human clinical cases and asymptomatic infections
by Province / Territory for the current Report Week and year to date, 2012 Season
Provinces and Territories October 21 to October 27, 2012 (Week 43)
West Nile virus Neurological syndrome
# cases
West Nile virus
Non-Neurological syndrome
# cases
Unclassified/
Unspecified
Total clinical
cases1
# of travel
related cases2
West Nile virus
asymptomatic infections3

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.
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.
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 (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.
4 Saskatchewan has ended WNV provincial surveillance program as of September 15th 2012. The final human case count in 2012 will be reported to PHAC by end of the season.

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 1 1 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan4 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 1 1 0 0
    Year to date: From January 1 to October 27, 2012
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 1 0 0 1 1 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 67 34 25 126 2 7
Ontario 61 168 20 249 13 10
Manitoba 6 28 5 39 2 0
Saskatchewan4 0 9 0 9 2 0
Alberta 4 5 0 9 2 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 139 244 50 433 22 17

Figure 2. WNV clinical cases and asympotomatic infections by report week 2012 season, compared to previous seasons

Table 2: Reported cumulative number of West Nile virus positive mosquito pools by Province/Territory and by report week, 2012 season *
Provinces and
Territories
Report weeks of 2012
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

*   Detailed West Nile virus mosquito surveillance data can be accessed through provincial/ territorial websites
** These Provinces are not conducting mosquito surveillance as part of their West Nile virus surveillance program at provincial level in 2012

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    
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    
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    
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    
Quebec ** 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 8 19 19 19 19 19 19 19 19 19 19 19    
Ontario 0 0 0 0 0 0 0 0 2 6 10 19 30 89 162 249 312 375 409 434 454 462 462 464 464 464 464    
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 2 20 48 62 98 108 111 116 116 116 116 116 116 116 116    
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 4 6 6 6 6 6 6 6 6 6 6    
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    
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    
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    
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    
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    

Figure 3. Reported number of dead birds testing positive for West Nile virus
by Province/Territory and by report week, 2012 season

Figure 4. Percentage of dead birds testing positive for WNv in the 2012 season
by report week as compared to the 2003 and 2011 seasons

figure 4
Text equivalent for figure 4