Media Bulletin - Office of the Chief Provincial Public Health Officer
September 20, 2007
WEST NILE VIRUS UPDATE #14
The chief medical officer of health advises that, as of the end of the day yesterday, 38 additional positive human test results for West Nile virus had been reported in Manitoba since last week. These new results mostly reflect exposures to infected mosquitoes in late August and early September.
To date, a total of 542 individuals have tested positive for West Nile virus (WNV) this year in Manitoba. Of these, 21 test results were identified by Canadian Blood Services routine screening. The donated blood units were discarded as planned.
This week, public health officials learned that an individual who had tested positive for West Nile virus had died. The public health investigation concluded that West Nile virus did not play a role in the death of this individual. In 2007, there have been three human deaths related to a West Nile virus infection in Manitoba.
Mosquito surveillance in southern Manitoba indicates the activity of Culex tarsalis, the main mosquito species that carries West Nile virus in Manitoba, is very low in all health regions.
While the risk of exposure to infected mosquitoes is very low at this time of year, personal protective precautions should be considered during warmer weather when mosquitoes are active.
Whenever mosquito activity is observed, Manitobans are encouraged to reduce the risk of mosquito bites by:
· using appropriate mosquito repellent;
· wearing light-coloured, loose-fitting clothing; and
· maintaining door and window screens so they fit tightly and are free of holes.
In 2003, 143 cases of West Nile virus were reported, of which 35 (approximately 24 per cent) were the more severe type of West Nile virus (WNV neurological syndrome). To date in 2007, 328 West Nile virus human cases have been classified of which 45 (approximately 14 per cent) are West Nile virus neurological syndrome.
As it becomes available, additional information on human cases including age, gender, regional health authority of residence and likeliest area of exposure will be provided on the province’s West Nile virus website at http://www.gov.mb.ca/health/wnv.
Information on weekly average trap counts of Culex tarsalis by regional health authority and a list of communities where infected mosquitoes have been found is also available on the website. Manitobans can continue to check the site regularly for up-to-date data and information.
More information about West Nile virus is also available from Health Links–Info Santé at 788-8200 or 1‑888‑315-9257.