2019 Surveillance Data for West Nile virus in Manitoba
- Positive West Nile virus (WNV) Surveillance Indicators
- Culex Tarsalis Mosquito Trap Catch by Health Region
- Positive Mosquito Collections (Adult) by Health Region
- WNV Human Cases by Health Region*
- Severity of WNV Human Cases
Positive West Nile virus (WNV) Surveillance Indicators*
| Surveillance Indicators** | 2019 | 2018 | 2017 | Historical Maximum |
| WNV Positive Mosquito Collections (Adults) | 7 | 167 | 41 | 943 |
| Human Cases (Total)*** | 2 | 32 | 5 | 540 |
* As of December 2, 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.
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 |
10 | 7 | 9 | 6 | 8 |
August 25 – August 31 |
< 1 |
2 |
1 |
1 |
1 |
Sept. 1 – Sept. 7 |
|||||
Sept. 8 – Sept. 14 |
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* As of September 6, 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.
Positive Mosquito Collections (Adult) by Health Region
| Positive Mosquito Collections (Adult) by Health Region | |
Interlake- Eastern |
2 |
Prairie Mountain |
3 |
Southern-Santé Sud |
2 |
Winnipeg |
0 |
| Total | 7 |
Mosquito samples from the following communities have tested positive for WNV in 2019: Boissevain, Brandon, Morden, Oakbank and Stonewall.
* As of September 6, 2019
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 |
2 |
2 |
| Total | 0 |
0 |
0 |
2 |
2 |
* As of December 2, 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.
Severity of WNV Human Cases
Asymptomatic |
West Nile Virus Non-Neurological Syndrome |
West Nile Virus Neurological Syndrome |
Under Investigation |
Total |
|
| Human Cases | 0 |
2 |
0 |
0 |
2 |
* As of December 2, 2019
Note: Subject to change as further information becomes available.
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
