The Office of the Chief Medical Officer of Health advises that three additional human cases have tested positive for West Nile virus during the 2008 season in Manitoba.
To date, a total of nine positive test results for West Nile virus have been reported in Manitoba in the 2008 season including one positive test result identified in a non-Manitoba resident.
One positive test result was identified through Canadian Blood Services routine screening and eight positive test results were identified through clinical testing at Cadham Provincial Laboratory.
Additional information on these cases, including age, gender, regional health authority of residence and likeliest area of exposure, will be provided on the website at www.gov.mb.ca/health/wnv.
Culex tarsalis mosquito samples testing positive for West Nile virus have been identified from the communities of Boissevain, Deloraine and Sioux Valley during the week of Aug. 24. Infected mosquitoes were previously identified in the communities of Beausejour, Brandon, Carberry, East St. Paul, Killarney, Selkirk, Stonewall, Virden and Winnipeg.
Preliminary results of mosquito testing from this week indicate the average numbers of Culex tarsalis mosquitoes found in surveillance traps have decreased in all southern Manitoban communities.
The risk of exposure to West Nile virus-infected mosquitoes in southern Manitoba is still present at this time. However, as the weather gets cooler, the risk is declining. As daytime and evening temperatures become cooler, Culex tarsalis mosquitoes may become more active during the day and early evening, with reduced activity overnight during cool temperatures.
No orders for adult mosquito control have been issued in 2008.
Whenever mosquitoes are active, 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.
Weekly average trap counts of Culex tarsalis by regional health authority are available on the province’s West Nile virus website at www.gov.mb.ca/health/wnv.
Information on the risk of West Nile virus will continue to be provided to the public throughout the season. Manitobans can also check the West Nile virus website regularly for up-to-date data and information.
For more information about West Nile virus, contact Health Links–Info Santé at 788-8200 or 1‑888‑315-9257 (toll-free) or visit the Manitoba Health website at www.gov.mb.ca/health/wnv.