2017 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
- Weekly WNV Surveillance Report
Positive West Nile virus (WNV) Surveillance Indicators*
| Surveillance Indicators** | 2017 | 2016 | 2015 | Historical Maximum |
| WNV Positive Mosquito Collections (Adults) | 41 | 39 | 30 | 948 |
| Human Cases (Total)*** | 5 | 23 | 5 | 585 |
| Horse Case | 1 | 3 | 1 | 236 |
* As of Septermber 15, 2017
** 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 21 – 27 |
No trapping |
0 |
0 |
0 |
0 |
May 28 – June 3 |
No trapping |
0 |
0 |
0 |
0 |
June 4 – June 10 |
0 |
2 |
0 |
< 1 |
< 1 |
June 11 – June 17 |
1 |
< 1 |
1 |
3 |
2 |
June 18 – June 24 |
1 |
2 |
1 |
< 1 |
1 |
| June 25 –July 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
July 2 – July 8 |
< 1 |
3 |
9 |
4 |
5 |
July 9 – July 15 |
3 |
47 |
15 |
11 |
22 |
July 16 – July 22 |
4 |
45 |
13 |
6 |
20 |
July 23 – July 29 |
4 |
42 |
17 |
10 |
21 |
July 30 – August 5 |
47 |
99 |
35 |
58 |
61 |
August 6 – August 12 |
5 |
29 |
14 |
18 |
18 |
August 13 – August 19 |
2 |
8 |
5 |
11 |
7 |
August 20 – August 26 |
5 |
18 |
9 |
9 |
11 |
August 27 – September 2 |
< 1 |
1 |
< 1 |
< 1 |
< 1 |
September 3 – September 9 |
0 |
1 |
< 1 |
< 1 |
< 1 |
September 10 – September 16 |
0 |
1 |
0 |
0 |
< 1 |
* As of Septermber 15, 2017
Permanent mosquito traps are set up in 29 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 Culex tarsalis mosquitoes per trap catch for the week by health region and provides a relative measure of the activity levels of Culex tarsalis from one region to another and over time. This measure is an indicator as to whether Culex 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 Culex 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 Culex 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 |
7 |
Prairie Mountain |
16 |
Southern-Santé Sud |
5 |
Winnipeg |
13 |
| Total | 41 |
Mosquito samples from the following communities have tested positive for WNV in 2017: Altona, Boissevain, Brandon, Carberry, Dauphin, East St Paul, Headingley, Minnedosa, Morden, Oakbank, Selkirk, Sioux Valley, Stonewall, Virden, Winkler and Winnipeg.
* As of Septermber 15, 2017
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 |
2 |
1 |
2 |
5 |
| Total | 0 |
2 |
1 |
2 |
5 |
* As of November 28, 2017
** 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 | 1 |
2 |
2 |
0 |
5 |
* As of November 28, 2017
Note: Subject to change as further information becomes available.
Weekly WNV Surveillance Report
- Weeks 36 & 37
- Week 35
- Week 34
- Week 33
- Week 32
- Week 31
- Week 30
- Week 29
- Week 28
- Week 27
- Week 26
- Week 25
- Week 24
- Week 23
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
