W is for West Nile Virus
1957 Israel – An outbreak of WNV is shown to produce meningioencephalitis in elderly patients.
1960s – Horses are effected in Egypt, France, and throughout Europe, southwest Asia, and Australia.
1999 College Point, Queens (New York City) – Horses, dogs, cats, and humans infected with WNV
From that initial point of contact in the USA, West Nile Virus, a mosquito-borne arbovirus spread rapidly across the country. Birds, specifically crows and Blue Jays, were found dead throughout the country. Local and state agencies began testing the birds and found West Nile Virus. Surprisingly, as it is a disease of temperate and tropical locations, not what comes to mind when you think of Wisconsin and Minnesota! For many years, the question of how WNV spread so quickly went unanswered. It was well documented that birds are the only species that can build up enough WNV to allow transmission to other species via mosquitoes. Migratory routes and other factors were taken into effect, but it still didn’t make sense. The crows and Blue Jays were dying, so how was the disease still spreading? The culprit was finally found in 2011 – the American Robin.
The American robin has a unique feature in that the mosquitoes that carry WNV love to feed on their blood (I wonder if I am part robin as they appear to feast upon me quite readily as well). The robin is a mainstay in the upper Midwest and has a large migratory pathway. Between the mosquitoes and the robins, they were able to quickly spread across country and since robins weren’t dying from the disease regularly, they were flying under the radar for testing.
Most people that contract WNV never have any symptoms. One in five people will develop flu like symptoms with fever, muscle aches, and lethargy being the biggest signs, and they can hang on for weeks to months, sometimes these may require hospitalization for IV fluids and other medications. Only 1% of all people infected will develop severe disease including meningitis and encephalitis. Of those individuals that develop neurologic signs, 10% will die.
There are no vaccinations for people, although there are WNV vaccines for horses.