Language selection

Government of Canada / Gouvernement du Canada

Search

Mosquito-borne disease surveillance report: September 1 to 7, 2019 (Week 36)

Download the alternative format
(PDF format, 1.10 Mb, 4 pages)

Organization: Public Health Agency of Canada

Date published: 2019-09-18

Related topics

Year-to-date snapshot
Year-to-date snapshot - Text equivalent

Between January 1, 2019, and September 7, 2019, 5 human cases of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (PHAC). Twenty-three WNV-positive birds, 71 WNV-positive mosquito pools, and 4 WNV-positive horse have been reported. In addition, 6 horses have tested positive for eastern equine encephalitis virus (EEEV) to date.

West Nile

Human epidemiology

As of surveillance week 36, ending on September 7, 2019, 5 human cases of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (PHAC) (Table 1). Of these, two cases in British Columbia and Ontario reported travel outside of Canada.

Table 1. Year-to-date (YTD) WNV human cases, by disease classification and province (January 1- August 31, 2019)
Province Clinical cases Total of clinical cases Footnote 1 Asymptomatic infections Footnote 2 YTD grand total Rate (per 100,000) Footnote 3
Neurological Non-neurological Unclassified
British Columbia 0 1 0 1 0 1 0.02
Alberta 0 0 0 0 0 0 0.00
Saskatchewan 0 - - 0 0 0 0.00
Manitoba 0 0 0 0 0 0 0.00
Ontario 0 1 1 2 1 3 0.02
Quebec 0 1 0 1 0 1 0.01
Maritime provinces 0 0 0 0 0 0 0.00
Territories 0 0 0 0 0 0 0.00
Total 0 3 1 4 1 5 0.01
Footnote 1

Clinical cases are the sum of confirmed and probable: WNV neurological and non-neurological syndromes, along with any unclassified.

Return to footnote 1 referrer

Footnote 2

Satisfies WNV diagnostic test criteria in the absence of clinical criteria (i.e., asymptomatic blood donors whose blood is screened by blood operators, Canadian Blood Services or Héma-Québec.

Return to footnote 2 referrer

Footnote 3

Calculated with grand total of clinical and asymptomatic cases, using Statistics Canada 2018 population estimates.

Return to footnote 3 referrer
Figure 1. Geographic distribution of WNV human clinical cases and asymptomatic infections in Canada, 2019
Figure 1 - Text equivalent

Since the start of the transmission season, 4 human cases of WNV have been reported to PHAC.

Mosquito, wild bird and equine epidemiology

As of week 36, PHAC has been notified of 9,572 mosquito pools tested for WNV. Of these, 71 (0.74%) were positive in Quebec (10), Ontario (55) and Manitoba (6) (Table 2).

Twenty-three of 51 dead wild birds have tested positive for WNV, by the Canadian Wildlife Health Cooperative (CWHC) in Saskatchewan (1), Ontario (17) and Quebec (5) (Table 3).

Since the start of this season, the Canadian Food Inspection Agency (CFIA) has reported 4 horses that tested positive for WNV in British Columbia (1), Saskatchewan (1), Alberta (1) and Quebec (1) (Table 3).

Figure 2. (A) WNV human clinical cases and asymptomatic infections, (B) positive WNV birds, and (C) percent positive mosquito pools by episode or report week, in Canada, 2019
Figure 2 - Text equivalent

Since the start of the transmission season, four human cases of West Nile virus have been reported to PHAC. A total of 23 birds and 0.74% of mosquito pools have tested positive for WNV in Canada and reported to PHAC.

Figure 2 footnotes

Footnote 1

Human cases includes clinical cases and asymptomatic infection.

Return to footnote 1 referrer

Footnote 2

Episode week is based on symptom onset or best available date including: diagnosis, lab sample or date reported.

Return to footnote 2 referrer

Footnote 3

Episode week is based off date of death or best available date including: date found, submitted, or received.

Return to footnote 3 referrer

Table 2. Year-to-date WNV positive pools and percent positive by province and nationally (January 1- September 7, 2019)
Province Footnote 1 Positive pools Total pools tested Percent positive
Saskatchewan 0 200 0.00 %
Manitoba 6 1,166 0.51 %
Ontario 55 6,807 0.81 %
Québec 10 1,399 0.71 %
Total 71 9,572 0.74 %
Footnote 1

Mosquito surveillance data is reported by the following four provinces: Saskatchewan, Manitoba Ontario and Quebec.

Return to footnote 1 referrer
Table 3. Number of WNV positive animal cases for current week and year to date (January 1- September 7, 2019)
Province Wild birds Footnote 1 Equine
Week 36 Year-to-date total Week 36 Year-to-date total
British Columbia 0 0 0 1
Alberta 0 0 0 1
Saskatchewan 0 1 0 1
Manitoba 0 0 0 0
Ontario 0 17 0 0
Quebec 0 5 0 1
Maritime provinces 0 0 0 0
Territories 0 0 0 0
Total 0 23 0 4
Footnote 1

Not all provinces conduct dead wild bird surveillance as part of their respective WNV surveillance program. However, WNV positive dead wild birds may be identified through the National Wildlife Disease Surveillance Program, CWHC or by specific provinces.

Return to footnote 1 referrer

California serogroup

As of September 7, 2019, no human exposures or cases of California serogroup virus have been reported by the National Microbiology Laboratory.

Eastern equine encephalitis

No human cases of EEEV have been reported to PHAC since the beginning of the 2019 transmission season.

The CFIA has reported 6 horses that tested 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:

Provincial

International

Notes

Thank you to all our partners for participating in the National WNV/MBD surveillance program.

Page details

Date modified: