Yellowknife (July 26/04) - Even though there are no doubt billions of mosquitoes in the NWT, surprisingly little is known about the annoying bugs that are here.

Netted headgear is your best protection if you are heading to the interior of the NWT anytime soon.

"Believe it or not, we have lots of mosquitoes, but very little information on what kinds of mosquitoes we have," says Andre Corriveau, the NWT's chief medical health officer.

"It's never been a large issue," says Brett Elkin, a wildlife veterinarian with RWED, in explaining the relatively few studies in the past.

However, that has changed with the continuing spread of the sometimes fatal West Nile virus across North America, even though it has not yet arrived in the NWT -- and might never arrive.

The virus affects certain birds, including crows, ravens, jays and magpies, and can be transmitted to humans by a particular species of "culex" mosquito.

Elkin says the culex has never been found in the NWT.

To gain better knowledge about NWT mosquitoes, RWED and Corriveau have partnered for a study on just what kinds of mosquito species exist here.

Beginning two weeks ago, traps were set in Yellowknife, Fort Simpson and Fort Smith to collect a weekly sampling of the bugs. They will be sent to an entomologist in Winnipeg to determine and count the various species.

Even though West Nile virus is not expected to hit the NWT, Elkin says "we basically want to know what species are here."

Based on previous studies, estimates of the number of species range up to 17.

The current study is tied into the West Nile Virus National Steering Committee, which is gathering information from across Canada.

The need to know

Only several small-scale studies of mosquitoes have been done in the NWT -- the most recent in 1991 -- and they are not of much value now because environmental conditions may have changed.

There are two species of culex mosquitoes involved in the transmission of West Nile virus -- one which spreads the virus among birds and another from birds to mammals.

It is known to be in Saskatchewan, Manitoba and parts of Alberta.

The 1991 study in Yellowknife found one species of culex mosquitoes -- just five per cent of the total population -- but not the species that carries West Nile virus.

"It would be comforting to know we don't have the mosquito and put people's minds at rest," Elkin says.

Results are expected from this summer's study by early fall.

Corriveau notes the culex mosquito likes the hotter and drier weather prevalent in the southern prairies.

"We wouldn't expect to see many of them (in the NWT), but you just don't know," he says.

Elkin points out there is another as-yet-unexplained factor protecting the NWT. All cases of West Nile virus have been in the south, where the grasslands meet the boreal forest, even though the carrier mosquitoes sometimes cross the boundary.

The veterinarian says a big question is why there seems to be that dividing line.

However, he adds, "it's extra breathing room for us."

While it is unlikely West Nile virus will arrive in the NWT, Corriveau says information is being distributed to advise Northerners travelling to the south.

The health care system in the NWT is also being readied to diagnose the disease if someone comes back from the south with it.

In milder cases, the symptoms may include fever and muscle aches, swollen lymph glands and sometimes a skin rash. In severe cases, symptoms may be sudden fever, intense headache, a stiff neck and confusion.

It could lead to encephalitis or meningitis.