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
Also see:
2005 Surveillance for West Nile virus
in Manitoba
2004 Surveillance for West Nile virus
in Manitoba
2003 Surveillance for West Nile virus
in Manitoba
Surveillance
Indicator |
2006* |
2005 |
2004 |
2003 |
2002 |
Corvids ** |
__ |
12 |
16 |
134 |
86 |
Mosquito Collections (Adult) |
171 |
193 |
57 |
290 |
15 |
Horse Cases |
1 |
4 |
0 |
47 |
236 |
Human Cases (Classified) |
51 |
58 |
3 |
143*** |
0 |
* As of November 20, 2006.
** The West Nile virus dead corvid pick up program was
not n effect in 2006. 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.
*** Updated in 2005 after receiving a late report on a Manitoba
resident with WNV who was investigated in Saskatchewan in
2003.
^ Return to Top
Average
Adult Culex tarsalis Mosquitoes per Weekly Trap
Catch |
Regional Health
Authority |
June
4-10 |
June
11-17 |
June
18-24 |
Assiniboine |
<1 |
<1 |
<1 |
Brandon |
<1 |
<1 |
<1 |
Central |
5 |
3 |
2 |
Interlake |
10 |
2 |
3 |
North Eastman |
4 |
<1 |
3 |
Parkland |
0 |
<1 |
<1 |
South Eastman |
6 |
1 |
2 |
Winnipeg |
13 |
2 |
1 |
Regional Health
Authority |
June
25-July 1 |
July
2-July 8 |
July
9-July 15 |
Assiniboine |
2 |
6 |
4 |
Brandon |
<1 |
2 |
8 |
Central |
11 |
15 |
8 |
Interlake |
14 |
33 |
24 |
North Eastman |
5 |
14 |
9 |
Parkland |
<1 |
<1 |
0 |
South Eastman |
4 |
13 |
13 |
Winnipeg |
18 |
21 |
19 |
Regional Health
Authority |
July
16-July 22 |
July
23-July 29 |
July
30-Aug 5 |
Assiniboine |
8 |
22 |
136 |
Brandon |
10 |
31 |
42 |
Central |
9 |
15 |
15 |
Interlake |
37 |
70 |
43 |
North Eastman |
20 |
17 |
11 |
Parkland |
0 |
<1 |
1 |
South Eastman |
11 |
15 |
5 |
Winnipeg |
50 |
83 |
98 |
Regional Health
Authority |
Aug
6-Aug 12 |
Aug
13-Aug 19 |
Aug
20-Aug 26 |
Assiniboine |
36 |
25 |
13 |
Brandon |
47 |
4 |
5 |
Central |
11 |
7 |
2 |
Interlake |
32 |
7 |
1 |
North Eastman |
9 |
7 |
1 |
Parkland |
1 |
0 |
0 |
South Eastman |
6 |
3 |
1 |
Winnipeg |
64 |
12 |
4 |
Regional Health
Authority |
Aug
27-Sept 2 |
Sept
3 -Sept 9 |
Sept
10 -Sept 16 |
Assiniboine |
2 |
<1 |
<1 |
Brandon |
2 |
<1 |
<1 |
Central |
<1 |
<1 |
<1 |
Interlake |
<1 |
0 |
<1 |
North Eastman |
<1 |
<1 |
0 |
Parkland |
0 |
0 |
<1 |
South Eastman |
<1 |
0 |
0 |
Winnipeg |
2 |
<1 |
<1 |
* As of November 20, 2006. (Routine mosquito
trapping ended the week of September 10, 2006.)
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.
^ Return to Top
Positive
Mosquito Collections (Adult) by RHA 2006 |
Assiniboine |
34 |
Brandon |
7 |
Central |
7 |
Interlake |
40 |
North Eastman |
9 |
Parkland |
0 |
South Eastman |
4 |
Winnipeg |
70 |
Total |
171 |
* As of November 20, 2006.
Mosquito samples from the following communities have tested
positive for WNV in 2006: Altona, Beausejour, Boissevain,
Brandon, Carberry, Carman, Deloraine, East St. Paul, Gimli,
Headingley, Killarney, Niverville, Oakbank, Portage la Prairie,
St. Andrews, Selkirk, Sioux Valley First Nation, Steinbach,
Stony Mountain, West St. Paul, Winkler, and Winnipeg.
^ Return to Top
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 |
Under
Investigation |
TOTAL |
Assiniboine |
0 |
6 |
0 |
0 |
6 |
Brandon |
0 |
0 |
0 |
0 |
0 |
Burntwood |
0 |
1 |
0 |
0 |
1 |
Central |
0 |
9 |
2 |
0 |
11 |
Interlake |
1 |
5 |
5 |
0 |
11 |
N. Eastman |
0 |
1 |
1 |
0 |
2 |
Parkland |
0 |
0 |
0 |
0 |
0 |
S. Eastman |
0 |
1 |
2 |
0 |
3 |
Winnipeg |
0 |
10 |
7 |
0 |
17 |
Total |
1 |
33 |
17 |
0 |
51 |
* As of November 20, 2006.
The most likely locations of exposure have been determined
for at least one human case in each of the following municipalities:
RM of Alexander, RM of Armstrong, RM of Brokenhead, RM of
Cartier, RM of Clanwilliam, RM of Coldwell, RM of De Salaberry,
RM of East St. Paul, RM of Louise, RM of MacDonald, Town of
Morden, RM of North Cypress, RM of Pilot Mound, RM of Portage
la Prairie, RM of Rockwood, RM of St. Andrews, RM of Ste.
Anne, RM of St. Clements, City of Selkirk, RM of Stanley,
Town of Stonewall, RM of Turtle Mountain, RM of Victoria Beach,
City of Winnipeg, RM of Woodlands.
Further information on likely locations of exposure will
be added as it becomes available. The risk of WNV, however,
exists throughout all of southern Manitoba and is not limited
to the communities listed. WNV has been identified in this
or previous years within the boundaries of all regional health
authorities except for NOR-MAN, Burntwood, and Churchill.
^ Return to Top
Age
in Years |
Asymptomatic |
West
Nile Virus Non-Neurological Syndrome |
West
Nile Virus
Neurological Syndrome |
Under
Investigation |
Total |
0 - 9 |
0 |
0 |
0 |
0 |
0 |
10 - 19 |
0 |
1 |
0 |
0 |
1 |
20 - 29 |
1 |
1 |
1 |
0 |
3 |
30 - 39 |
0 |
4 |
1 |
0 |
5 |
40 - 49 |
0 |
9 |
6 |
0 |
15 |
50 - 59 |
0 |
10 |
4 |
0 |
14 |
60 - 69 |
0 |
4 |
1 |
0 |
5 |
Over 70 |
0 |
4 |
4 |
0 |
8 |
Total |
1 |
33 |
17 |
0 |
51 |
Average Age - West Nile Virus Neurological
Syndrome: 53.2
Average Age - West Nile Virus Non-Neurological
Syndrome: 51
* As of November 20, 2006.
^ Return to Top
Gender |
Asymptomatic |
West Nile Virus Non-Neurological
Syndrome |
West Nile Virus
Neurological Syndrome |
Under
Investigation |
Total |
Male |
0 |
24 |
9 |
0 |
33 |
Female |
1 |
9 |
8 |
0 |
18 |
Total |
1 |
33 |
17 |
0 |
51 |
* As of November 20, 2006.
^ Return to Top
Additional information and maps are available at the
Health Canada website. |