Manitoba Health reports that Manitoba’s mosquito surveillance program has identified the first Culex tarsalis mosquito samples infected with West Nile virus in 2010.
The infected mosquitoes were collected during the week of July 4 from an adult mosquito trap in West St. Paul. Based on the most recent information, the numbers of infected mosquitoes are predicted to be low for this area. The current estimated risk does not warrant an order for adult mosquito control at this time.
The numbers of Culex tarsalis mosquitoes trapped during the week of July 4 increased throughout southern Manitoba. The mosquito numbers are highest in the Red River Valley and southeast Manitoba at this time but the potential for human exposure to infected mosquitoes is present throughout southern Manitoba. Mosquito samples that are positive for West Nile virus may be identified in additional communities in the next few weeks.
Preliminary trap information for the week of July 11 indicates the numbers of Culex tarsalis mosquitoes have decreased slightly from the previous week. Cooler weather may have reduced mosquito activity. The risk of exposure to West Nile virus is expected to continue to increase in the coming weeks, particularly with warm weather. Taking measures to prevent mosquito bites and reducing standing water around the home can help reduce the risk of West Nile virus exposure.
To date, no human cases of West Nile virus have been identified in Manitoba in the 2010 season.
The proportion of Culex tarsalis mosquitoes collected in the traps compared to other mosquitoes is increasing. 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.
The province offers a cost-shared larviciding program for municipalities and communities to take steps to help control Culex tarsalis mosquitoes. To date this year, 55 communities are participating in the program.
Information on the risk of West Nile virus will continue to be provided to the public throughout the summer in a media campaign and at various fairs and festivals. Manitobans can also check the West Nile virus website regularly for up-to-date data and information.
