2019 Surveillance Data for West Nile virus in Manitoba


Positive West Nile virus (WNV) Surveillance Indicators*
Surveillance Indicators** 2019 2018 2017 Historical Maximum
WNV Positive Mosquito Collections (Adults) 3 152 37 894
Human Cases (Total)*** 0 28 4 431

* As of August 23, 2019

** The historical comparison data is based on the same period of time for each year represented in the table above.

*** Additional information on these cases including classification, severity and health region of residence is available here.

^ Back to Top


Culex Tarsalis Mosquito Trap Catch by Health Region
Trapping Week Health Region Manitoba
Interlake-Eastern Prairie Mountain Southern-Santé Sud Winnipeg

May 19 – 25

No trapping
No trapping
0
0
0

May 26 – June 1

No trapping
No trapping
0
0
0

June 2 – June 8

0
No trapping
0
0
0

June 9 – June 15

0
0
< 1
< 1
< 1

June 16 – June 22

< 1
< 1
< 1
< 1
< 1

June 23 – June 29

2 1 < 1 < 1 1

June 30 – July 6

1 5 1 1 2

July 7 – July 13

17 21 20 14 18

July 14 – July 20

17 113 27 13 45

July 21 – July 27

7 50 13 5 20

July 28 – August 3

27 100 58 52 62

August 4 – August 10

49 99 101 39 78

August 11 – August 17

14 16 9 12 12

August 18 – August 24

         

August 25 – August 31

         

Sept. 1 – Sept. 7

         

Sept. 8 – Sept. 14

         

* As of August 23, 2019

Permanent mosquito traps are set up in 28 community areas in southern Manitoba to monitor Culex tarsalis mosquitoes, the mosquitoes that are most likely to transmit West Nile virus to humans in Manitoba. The above table will represent the average number of Cx. tarsalis mosquitoes per trap catch for the week by health region and provides a relative measure of the activity levels of Cx. tarsalis from one region to another and over time. This measure is an indicator as to whether Cx. tarsalis mosquito populations are rising or falling or staying steady. It should be noted that these health region averages provide an approximate indication of the number of Cx. tarsalis in the health region, counts in specific locations within the health region will vary depending on local conditions, temperature, precipitation, etc.

Note:  normally, two Centers for Disease Control (CDC) mosquito traps baited with carbon dioxide are run for two nights each week in each Manitoba community except Winnipeg and Brandon (where proportionately more traps are used because of larger community size).

The average number of Cx. tarsalis per trap catch (a trap catch – may also be called a "collection"- represents the mosquitoes collected by one trap during one night from approximately one hour before sunset until approximately one hour after sunrise) is calculated by dividing the total number of Culex tarsalis collected for the whole week in a given health region by the number of collections.

 ^ Back to Top


Positive Mosquito Collections (Adult) by Health Region
Positive Mosquito Collections (Adult) by Health Region

Interlake- Eastern

2

Prairie Mountain

1

Southern-Santé Sud

0

Winnipeg

0

Total
3

Mosquito samples from the following communities have tested positive for WNV in 2019:  Boissevain and Stonewall.

* As of August 23, 2019

 ^ Back to Top


WNV Human Cases by Health Region*
Classification
Health Region**
Total
Interlake-Eastern
Prairie Mountain
Southern-Santé Sud
Winnipeg
Probable

0

0

0

0

0

Confirmed

0

0

0

0

0

Total
0
0
0
0
0

* As of August 23, 2019

** Based on region of residence. Note that region of residence may not correspond to region of likely exposure.

Note:  Subject to change as further information becomes available.

 ^ Back to Top


Severity of WNV Human Cases
 
Asymptomatic
West Nile Virus
Non-Neurological Syndrome
West Nile Virus Neurological Syndrome
Under
Investigation
Total
Human Cases
0
0
0
0
0

* As of August 23, 2019

Note:  Subject to change as further information becomes available.

^ Back to Top


Additional information and maps are available at the Public Health Agency of Canada website.


For WNV health concerns, contact your doctor or call:

Health Links - Info Santé
204-788-8200
(Winnipeg) or toll-free 1-888-315-9257