It's been a quiet summer so far on the West Nile front, but provincial health officials are warning Manitobans not to let their guard down.
The virus has not yet been detected in the province -- or across Canada -- so far this season, although it has shown up in mosquitoes collected in the Dakotas and Minnesota.
Last year, there were 19 West Nile virus-positive mosquito pools collected from 10 communities across southern Manitoba, including the city of Winnipeg. Three human cases of West Nile were reported, and one elderly man died of the disease -- the first fatality attributed to West Nile virus since 2008.
The West Nile virus is spread by a specific type of mosquito -- the Culex tarsalis, which passes the disease by feeding off infected birds and then biting humans.
The number of Culex mosquitoes has fluctuated this summer in Manitoba, says the province's West Nile website.
Preliminary results for the past week indicate they are again on the rise. In recent weeks, the communities of Oakbank, West St. Paul and Morris have seen some of the highest Culex counts.
Dr. Richard Rusk, Manitoba's chief occupational medical officer and medical officer of health zoonotics and enterics, said Manitobans should take precautions against the virus by avoiding bites and clearing properties of standing water.
While the disease has not manifested itself yet this year, it's still mid-season for contracting the virus, he said Monday.
To reduce the risk of mosquito bites and West Nile virus, Manitobans are encouraged to:
-- Reduce the amount of time spent outdoors during peak mosquito hours between dusk and dawn.
-- Use appropriate mosquito repellent.
-- Wear light-coloured, loose-fitting clothing.
-- Maintain door and window screens so they fit tightly and are free of holes.
Manitobans can also reduce the number of mosquitoes around their home by eliminating standing water. To reduce standing water:
-- Clean eavestroughs and regularly empty bird baths and other items that might collect water.
-- Ensure rain barrels are covered with mosquito screening or are tightly sealed around the downspout.
-- Clear yards of old tires or other items that collect water.
Human cases of West Nile virus were first reported in Manitoba in 2003. Last summer's death was the eighth since the province began collecting this information. In 2007, there were 587 reported cases of West Nile. That year, four Manitobans died of the disease.