2011 Surveillance for West Nile virus in Manitoba
Positive Surveillance Indicators*
Surveillance Indicator 2011 2010 2009
Corvids 1 __ __ __
Mosquito Collections (Adult)
0
20
2
Horse Cases
0
0
0
Human Cases (Total) 2 0 0 2
Surveillance Indicator 2008 2007 2006
Corvids 1 __ __ __
Mosquito Collections (Adult) 41 948 171
Horse Cases 0 8 1
Human Cases (Total) 2 12 587 51
Surveillance Indicator 2005 2004 2003
Corvids 1 12 16 134
Mosquito Collections (Adult) 193 57 290
Horse Cases 4 0 47
Human Cases (Total) 2 58 3 143

* As of September 29, 2011

1The West Nile virus dead corvid pick up program is not in effect in 2011. 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.

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Culex tarsalis Mosquito Trap Catch by Regional Health Authority*
Regional Health Authority   September 11 –
September 17 		September 4 –
September 10
Assiniboine   <1 <1
Brandon   <1 <1
Central   3 2
Interlake   <1 <1
North Eastman   0 0
Parkland   - 0
South Eastman   <1 0
Winnipeg   <1 <1
Manitoba   <1 <1
Regional Health Authority

August 28 –
September 3

 August 21 –
August 27 		August 14 –
August 20
Assiniboine 7 6 22
Brandon 1 4 5
Central 15 10 75
Interlake 2 6 3
North Eastman <1 <1 <1
Parkland 0 0 1
South Eastman <1 <1 <1
Winnipeg 6 9 4
Manitoba 6 6 19
Regional Health Authority

August 7 –
August 13

July 31 –
August 6

 July 24 -
July 30
Assiniboine 18 15 6
Brandon 5 10 9
Central 43 21 23
Interlake 9 9 4
North Eastman 3 <1 <1
Parkland <1 0 <1
South Eastman 1 1 <1
Winnipeg 10 7 4
Manitoba 16 11 8
Regional Health Authority July 17 -
July 23

July 10 -
July 16

July 3 -
July 9
Assiniboine 7 4 5
Brandon 10 3 2
Central 17 29 11
Interlake 5 8 11
North Eastman 1 2 1
Parkland 0 12 0
South Eastman 2 3 1
Winnipeg 3 6 4
Manitoba 7 10 6
Regional Health Authority

June 26 -
July 2

June 19 -
June 25

June 12 -
June 18
Assiniboine <1 <1 <1
Brandon 0 0 0
Central 1 3 <1
Interlake 2 1 <1
North Eastman 0 0 <1
Parkland 0 0 0
South Eastman <1 <1 0
Winnipeg <1 <1 0
Manitoba <1 <1 <1
Regional Health Authority

June 5 -
June 11

May 29 -
June 4

May 22 -
May 28
Assiniboine 0 0 0
Brandon 0 0 0
Central <1 0 0
Interlake <1 0 0
North Eastman 0 0 0
Parkland 0 0 0
South Eastman 0 0 0
Winnipeg <1 0 0
Manitoba <1 0 0

* As of September 29, 2011

NOTE:  Routine mosquito trapping was discontinued the week ending September 10, 2011.  Reduced trapping in representative communities occurred the week ending September 17, 2011.

Permanent mosquito traps are set up in 36 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.

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Positive Mosquito Collections (Adult) by RHA*
Positive Mosquito Collections (Adult) by RHA
Assiniboine
0
Brandon
0
Central
0
Interlake
0
North Eastman
0
Parkland
0
South Eastman
0
Winnipeg
0
Total
0

* As of September 29, 2011

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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
Assiniboine
0
0
0
0
0
Brandon
0
0
0
0
0
Central
0
0
0
0
0
Interlake
0
0
0
0
0
NorMan
0
0
0
0
0
North Eastman
0
0
0
0
0
Parkland
0
0
0
0
0
South Eastman
0
0
0
0
0
Winnipeg
0
0
0
0
0
Total
0
0
0
0
0
Out of Province
0
0
0
0
0

* As of September 29, 2011

Note: 2011 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.

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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
0
0
0
0
40 - 49
0
0
0
0
0
50 - 59
0
0
0
0
0
60 - 69
0
0
0
0
0
Over 70
0
0
0
0
0
Total
0
0
0
0
0

* As of September 29, 2011

Note: 2011 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.

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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
0
0
0
Female
0
0
0
0
0
Total
0
0
0
0
0

* As of September 29, 2011

Note: 2011 human case classifications include both final and preliminary classifications and may be subject to change as further information becomes available.

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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