September 15, 2005
Current mosquito surveillance in southern Manitoba indicates the activity of Culex tarsalis, the main mosquito species that carries West Nile virus in Manitoba, was low in all regional health authorities during the week of Sept. 4 to 10. Preliminary evidence from this week’s sample trap data indicates the number of Culex tarsalis mosquitoes have declined further.
Effective today, ministerial orders for adult mosquito control have been discontinued in Winnipeg, Winkler, Carman, the R.M. of West St. Paul and the R.M. of East St. Paul. Adult mosquito control has not taken place under the orders in Manitoba since Aug. 15.
Routine trapping for adult mosquitoes ended last week in most communities. As weather conditions are favourable, monitoring of adult mosquitoes continues in some communities in southern Manitoba.
While the risk of exposure to infected mosquitoes is low, mosquito surveillance during the week of Sept. 4 to 10 indicated there were still small numbers of infected mosquitoes in southern Manitoba. Therefore, during September, personal protective precautions should be considered during warmer weather when mosquitoes are active.
Manitobans can reduce the risk of mosquito bites by:
checking that door and window screens fit tightly and are free of holes;
reducing the amount of time spent outdoors whenever mosquitoes are active;
wearing light-coloured, loose-fitting clothing; and
using appropriate mosquito repellent.
Bird surveillance for West Nile virus in the Nor-man, Burntwood and Churchill regional health authorities will end tomorrow. No positive birds have been identified in these areas.
Since last week’s update, seven more Manitobans have tested positive for West Nile virus. This brings the total number of Manitobans who have tested positive for West Nile virus this year to 49.
Following investigations by public health officials, 39 human cases have been classified at this time.
Ten cases are classified are probable cases of West Nile neurological syndrome.
Twenty-six cases are classified as probable cases of West Nile non-neurological syndrome.
Three cases identified by Canadian Blood Services are confirmed as asymptomatic cases of West Nile virus.
The remaining 10 cases are currently under investigation to determine their status.
One human death related to West Nile virus infection in Manitoba this year was reported on Aug. 31. The role West Nile virus played in this death is still under investigation.
The 39 classified cases reside within the boundaries of seven regional health authorities in southern Manitoba:
Winnipeg Regional Health Authority – 12;
Assiniboine Regional Health Authority – 11;
Central Regional Health Authority – eight;
South Eastman Regional Health Authority – three;
Interlake Regional Health Authority – two;
Brandon Regional Health Authority – two; and
North Eastman Regional Health Authority – one.
Further information on human cases will be posted on the website when it becomes available. Most of these human cases reflect exposures to West Nile virus infected mosquitoes during July and August. So far this year, 1,876 people have been tested for WNV in Manitoba.
Public information about West Nile virus is available by calling Health Links-Info Santé at 788‑8200 in Winnipeg or toll-free at 1-888-315-9257. Information is also available on the Manitoba Health website at http://www.gov.mb.ca/health/wnv.
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