Mosquito-borne diseases surveillance report: September 27 to October 24, 2021 (Week 39 to 42)
Organization: Public Health Agency of Canada
Date published: 2021-11-17
As of surveillance week 42, ending on October 24, 2021, 29 clinical human cases and five asymptomatic human case of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (PHAC) (Table 1).
|Province||Clinical cases||Total of clinical cases Footnote 1||Asymptomatic infections Footnote 2||YTD grand total||Rate (per 100,000) Footnote 3|
Mosquito, wild bird and equine epidemiology
As of week 42, PHAC has been notified of 17, 229 mosquito pools tested for WNV in Canada. Of these, there have been 10 WNV-positive mosquito pools identified in Québec, 104 in Ontario, 116 in Manitoba and 9 in Saskatchewan (Table 2).
22 wild birds have tested positive WNV by the by the Canadian Wildlife Health Cooperative 14 in Québec and 8 in Ontario (Table 3). The province of Québec reported additional positive bird and the province of Manitoba reported three birds that tested positive for WNV.
Since the start of this season, the Canadian Food Inspection Agency (CFIA) has identified equine cases that tested positive for WNV in Alberta (1), Saskatchewan (8), Manitoba (6) and Ontario (3) (Table 3). The province of Saskatchewan reported two additional horses that tested positive for WNV.
Figure 2 - Legend
- Human cases includes clinical cases and asymptomatic infection.
- Episode week is based on symptom onset or best available date including: diagnosis, lab sample or date reported.
- Episode week is based off date of death or best available date including: date found, submitted, or received.
|ProvinceFootnote 1||Positive pools||Total pools tested||Percent positive|
|Province||Wild birdsFootnote 1||Equine|
As of October 24th, 2021, one human case of California serogroup virus was diagnosed by the National Microbiology Laboratory in Canada: Ontario (1). The case was further classified as Jamestown Canyon virus.
Eastern equine encephalitis
No human cases of EEEV have been reported to PHAC since the beginning of the 2021 transmission season.
The CFIA has reported seven horse cases testing positive for Eastern Equine Encephalitis virus (EEEV) in Ontario.
Provincial/territorial and international surveillance links
Data reported to PHAC is subject to change and may differ from provincial webpages due to reporting timelines. To obtain the latest arbovirus surveillance data, please refer to the following jurisdictional/regional webpages:
Thank you to all our partners for participating in the National WNV/MBD surveillance program.
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