2013 Surveillance for West Nile virus in Manitoba
- Positive Surveillance Indicators
- Culex tarsalis Mosquito Trap Catch by Regional Health Authority
- Positive Mosquito Collections (Adult) by RHA
- WNV Patients by Regional Health Authority
- Severity of WNV Disease by Age
- WNV Disease by Gender
- Weekly WNV Surveillance Report
Positive Surveillance Indicators*
| Surveillance Indicator | 2013 | 2012 | 2011 |
Corvids 1 |
__ |
__ |
__ |
Mosquito Collections (Adult) |
19 |
116 |
0 |
Horse Cases |
1 |
7 |
0 |
Human Cases (Total) 2 |
3 |
39 |
0 |
| Surveillance Indicator | 2010 | 2009 | 2008 |
Corvids 1 |
__ |
__ |
__ |
Mosquito Collections (Adult) |
20 |
2 |
41 |
Horse Cases |
0 |
0 |
0 |
Human Cases (Total) 2 |
0 |
2 |
12 |
| Surveillance Indicator | 2007 | 2006 | 2005 |
Corvids 1 |
__ |
__ |
12 |
Mosquito Collections (Adult) |
948 |
171 |
193 |
Horse Cases |
8 |
1 |
4 |
Human Cases (Total) 2 |
587 |
51 |
58 |
| Surveillance Indicator | 2004 | 2003 | 2002 |
Corvids 1 |
16 |
134 |
86 |
Mosquito Collections (Adult) |
57 |
290 |
15 |
Horse Cases |
0 |
47 |
236 |
Human Cases (Total) 2 |
3 |
143 |
0 |
* As of December 12, 2013
1The West Nile virus dead corvid pick up program is not in effect in 2013. Dead corvids are no longer needed as an early indicator of West Nile virus in Manitoba or to determine geographic distribution. Larval sampling, mosquito sampling and testing in addition to other factors (temperature, etc.) will be used to guide the assessment of risk of West Nile virus exposure.
2Additional information on these cases including classification, age, gender, regional health authority of residence and likeliest area of exposure is available here.
One bird submitted to the Canadian Cooperative Wildlife Health Centre (University of Saskatchewan) in 2013 has tested positive for WNV.
Culex tarsalis Mosquito Trap Catch by Regional Health Authority*
| Regional Health Authority | May 19 - 25 | May 26 - June 1 | June 2 - 8 |
Interlake- Eastern 1 |
0 |
0 |
0 |
Southern Health-Santé Sud 2 |
0 |
0 |
0 |
Prairie Mountain Health 3 |
0 |
0 |
0 |
Winnipeg |
0 |
0 |
0 |
| Manitoba | 0 | 0 | 0 |
| Regional Health Authority | June 9 - 15 | June 16 - 22 | June 23 - 29 |
Interlake- Eastern 1 |
<1 |
<1 |
<1 |
Southern Health-Santé Sud 2 |
<1 |
<1 |
3 |
Prairie Mountain Health 3 |
<1 |
<1 |
1 |
Winnipeg |
<1 |
<1 |
<1 |
| Manitoba | <1 | <1 | 1 |
| Regional Health Authority | June 30 - July 6 | July 7 - 13 | July 14 - 20 |
| Interlake- Eastern 1 | <1 | 4 | 18 |
| Southern Health-Santé Sud 2 | 8 | 18 | 71 |
| Prairie Mountain Health 3 | 1 | 9 | 9 |
| Winnipeg | 1 | 15 | 31 |
| Manitoba | 3 | 13 | 36 |
| Regional Health Authority | July 21 - 27 | July 28 - August 3 | August 4 - 10 |
| Interlake- Eastern 1 | 21 | 5 | 3 |
| Southern Health-Santé Sud 2 | 67 | 20 | 23 |
| Prairie Mountain Health 3 | 16 | 2 | 5 |
| Winnipeg | 26 | 6 | 4 |
| Manitoba | 36 | 9 | 10 |
| Regional Health Authority | August 11 - 17 | August 18 - 24 | August 25 - 31 |
| Interlake- Eastern 1 | 1 | 3 | 4 |
| Southern Health-Santé Sud 2 | 4 | 23 | 9 |
| Prairie Mountain Health 3 | 7 | 34 | 15 |
| Winnipeg | 1 | 15 | 9 |
| Manitoba | 3 | 21 | 10 |
| Regional Health Authority | September 1 - September 7 |
September 8 - September 14 |
|
| Interlake- Eastern 1 | <1 | 0 | |
| Southern Health-Santé Sud 2 | 1 | 1 | |
| Prairie Mountain Health 3 | 2 | 1 | |
| Winnipeg | 1 | <1 | |
| Manitoba | 1 | 1 |
1 Includes the former Interlake and North Eastman RHAs
2 Includes the former Central and South Eastman RHAs
3 Includes the former Assiniboine, Brandon and Parkland RHAs.
* As of December 12, 2013
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 Regional Health Authority (RHA) and provides a relative measure of the activity levels of Culex tarsalis from one RHA 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 RHA averages provide an approximate indication of the number of Culex tarsalis in the RHA, counts in specific locations within the RHA 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 RHA by the number of collections.
Based on the time of year and declining Culex tarsalis numbers, reduced trapping commenced on the weekend of September 8 . All trapping has now concluded for the 2013 season.
Positive Mosquito Collections (Adult) by RHA*
| Positive Mosquito Collections (Adult) by RHA | |
Interlake- Eastern 1 |
0 |
Southern Health-Santé Sud 2 |
12 |
Prairie Mountain Health 3 |
3 |
Winnipeg |
4 |
| Total | 19 |
Mosquito samples from the following communities have tested positive for WNV in 2013: Altona, Boissevain, Carberry, Killarney, Morden, Morris, Portage la Prairie, West St. Paul, Winkler, Winnipeg.
1 Includes the former Interlake and North Eastman RHAs
2 Includes the former Central and South Eastman RHAs
3 Includes the former Assiniboine, Brandon and Parkland RHAs.
* As of December 12, 2013
WNV Human Cases by Regional Health Authority*
Represents the Regional Health Authority of residence of the patient.
| Regional Health Authority |
Asymptomatic | West Nile Virus Non-Neurological Syndrome | West
Nile Virus Neurological Syndrome |
Unclassified Positive Test Results |
TOTAL |
Interlake- Eastern 1 |
0 |
0 |
1 |
0 |
1 |
Northern 2 |
0 |
0 |
0 |
0 |
0 |
Southern Health-Santé Sud 3 |
0 |
1 |
0 |
0 |
1 |
Prairie Mountain Health 4 |
0 |
0 |
0 |
0 |
0 |
Winnipeg |
0 |
1 |
0 |
0 |
1 |
| Total | 0 |
2 |
1 |
0 |
3 |
| Out of Province | 0 |
0 |
0 |
0 |
0 |
1 Includes the former Interlake and North Eastman RHAs
2 Includes the former Burntwood and NorMan RHAs
3 Includes the former Central and South Eastman RHAs
4 Includes the former Assiniboine, Brandon and Parkland RHAs.
* As of December 12, 2013 - May include cases pending classification
Note: 2013 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.
Severity of WNV Disease By Age*
| Age in Years | Asymptomatic | West Nile Virus Non-Neurological Syndrome | West
Nile Virus Neurological Syndrome |
Unclassified Positive Test Results |
Total |
| 0 - 9 | 0 |
0 |
0 |
0 |
0 |
| 10 - 19 | 0 |
0 |
0 |
0 |
0 |
| 20 - 29 | 0 |
0 |
0 |
0 |
0 |
| 30 - 39 | 0 |
1 |
0 |
0 |
1 |
| 40 - 49 | 0 |
1 |
0 |
0 |
1 |
| 50 - 59 | 0 |
0 |
0 |
0 |
0 |
| 60 - 69 | 0 |
0 |
0 |
0 |
0 |
| Over 70 | 0 |
0 |
1 |
0 |
1 |
| Total | 0 |
2 |
1 |
0 |
3 |
* As of December 12, 2013 - May include cases pending classification
Note: 2013 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.
WNV Disease by Gender*
| Gender | Asymptomatic | West Nile Virus Non-Neurological Syndrome | West Nile Virus Neurological Syndrome |
Unclassified Positive Test Results |
Total |
Male |
0 |
0 |
1 |
0 |
1 |
Female |
0 |
2 |
0 |
0 |
2 |
| Total | 0 |
2 |
1 |
0 |
3 |
* As of December 12, 2013 - May include cases pending classification
Note: 2013 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.
Weekly WNV Surveillance Report
- Week 37
- Week 36
- Week 35
- Week 34
- Week 33
- Week 32
- Week 31
- Week 30
- Week 29
- Week 28
- Week 27
- Week 26
- Week 25
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
