West Nile Virus

These days it is a rare event to find an ideal day when the wind is not howling, the rain is not falling, the sun is shining, the temperature is just right and the bugs are not getting into your ears, nose and throat.

Then there are ants. Many houses are swamped by the ants but not many people talk about that. Then there are many other kinds of worms and insects taking over the trees, backyards, parks and barbeque areas.

Do you get a feeling that you are under siege?

I have been worried about the West Nile virus (WNV). But my fears were partially alleviated by the recent announcement by Palliser Health Region’s medical officer of health who said the WNV hasn’t showed up in mosquitoes, birds, horses or humans in southern Alberta yet.

The Corvidae family of birds, which includes crows, blue and grey jays, ravens and magpies, are particularly susceptible to illness and death from WNV. Public health units have relied on dead crow sightings, the testing of standing water for the presence of mosquito larvae and the trapping of adult mosquitoes for WNV testing to monitor control efforts.

When I lived in Africa, I was not threatened by the lions or the elephants. I felt threatened by malaria carrying mosquitoes. Malaria is a life-threatening parasitic disease transmitted by mosquitoes. Today, approximately 40 per cent of the world’s population, mostly those living in the world’s poorest countries, is at risk of malaria. It causes more than 300 million acute illnesses and at least one million deaths a year.

Africa is also the source WNV. It was first isolated in 1937 from the blood of a patient on the West Nile province of Uganda. The man had fever. Initially, the outbreaks of the disease were few. But in the last 10 years the numbers have increased. In North America, the virus was first detected in New York 1999. From there it was exported to Ontario and rest of Canada.

Statistically, a person’s risk of contracting West Nile is low. Less than one per cent of those infected develop serious illness from the virus. Those at highest risk for serious illness are the elderly and those with lowered immune systems. However, people of all ages can develop serious illness. Most cases of WNV are mild and self-resolving. But one per cent of cases the virus infects the nervous system and this can be serious. It may result in long term disability, coma and death.

Humans can be infected with WNV by a mosquito bite, through blood and organ donation, pregnancy, lactation, needle-stick injury and exposure to infected laboratory specimens.

WNV incubates for three to 14 days in humans. Only 20 per cent of infected people have fever. Fever is accompanied by malaise, headache, muscle pain, rash, enlarged lymph glands, eye pain, loss of appetite and vomiting lasting for three to six days.

Currently, prevention is the best way to keep the virus away from our body. How do we do that?
-By elimination of mosquito breeding sites (standing water). Many mosquitoes will breed in containers that hold water, such as flowerpots or discarded tires.
-By the use of personal protection. One survey showed that only less than eight per cent of the public consistently used an insect repellent containing DEET during outdoor activities.

Once again, it boils down to prevention. Enjoy the summer safely!

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