West Nile testing set to resume

The Northwestern Health Unit is gearing up for a sixth season of monitoring the West Nile virus in the Kenora-Rainy River districts and, starting May 28, once again will be accepting dead crows and ravens suspected of virus-caused deaths.
Al Mathers, environmental health officer with the health unit, said the program will run the same as last year.
If any member of the public finds what they think is a bird that may have died from a West Nile-infected mosquito, report it to the health unit.
Last year, about 40 birds were sent away for testing, with about 15 coming back positive for West Nile.
“What was interesting last year was the rise of positive birds that we got early in the year,” said Mathers. “And we did get one human case of West Nile virus last year in the Dryden area.”
Mathers noted the mosquito population is affected by the weather and moisture level, but a wet season doesn’t necessarily translate into increased West Nile activity.
“Last year, when w did the get the human case, we had gone through a drought period,” he remarked. “The mosquitoes that are most involved in the transmission of the virus is basically an urban mosquito.
“These mosquitoes like to hang around in storm sewer areas where they have a very small volume of water at the bottom of the pump pit.
“The problem was last year is they weren’t getting flushed out. That gave them the opportunity to get a toehold—it was a lack of water to flush out the storm sewers,” he explained.
“That’s only a theory on my part, but it does hold some water.”
To report a suspiciously dead crow or raven, contact the health unit office here during normal office hours or call the after-hours number (1-807-468-7109).
If the bird is suitable, the health unit will pick it up and send it away for testing at the University of Guelph.
If you are told by the health unit that the bird is not suitable for testing, bury it under at least two feet of earth or place it in two leak-proof bags and discard it in the garbage.
Updates on any positive test results will be provided if or when they occur, Mathers said.
Since the point of the bird collection program is to determine where the virus has manifested in any of the communities in the health unit’s catchment area, once that’s been verified, Mathers said there’s no point in sending in more dead birds from those areas for testing that season.
In related news, Mathers said the provincial campaign to monitor West Nile virus by collecting mosquito samples will continue this year, with “mosquito traps” set up Fort Frances, Kenora, Dryden, and in the west end of Rainy River District.
Health unit staff in all these areas will use the traps to collect mosquito samples from late June to September. The purpose is to determine what species of mosquito are most common in the two districts.
This is the fifth year for this campaign.
Last year, several samples sent away for testing came back positive for the West Nile virus—two from traps in the Fort Frances area and one from Dryden.
That said, only a small percentage of all the samples collected in the region were specimens of the main virus-carrying mosquito species, the Culex (or common house mosquito).
This means the chances of seeing the Culex breed (and thus the virus) here remain slim, said Mathers.
Mosquito season usually tapers off in September, Mathers noted, adding any mosquitoes spotted in the latter part of that month are not likely looking for a “blood meal,” but instead simply are interested in finding a place to go into stasis for the winter.
Mosquito activity normally drops off after the temperatures at night are at an average of 10 C, he added.
West Nile virus is spread to humans by the bite of an infected mosquito. Mosquitoes become infected by biting an infected bird.
Crows and ravens are particularly susceptible to the virus and thus serve as an effective early-warning indicator.
The virus is not spread by person-to-person contact, and it cannot be spread directly from bird to human, according to the health unit.
The risk of becoming seriously ill as a result of an infection with West Nile virus is low.
In fact, most people who become infected experience no symptoms or have a very mild illness, with fever, headache, muscle weakness, or body aches, the health unit reported.
Those at increased risk of severe illness are individuals over age 50 and people with weakened immune systems.
Symptoms of West Nile virus encephalitis (the rare, serious form of the disease) include severe headache, stiff neck, nausea, and vomiting, as well as altered levels of consciousness and mental states.