Blue Ridge Wildlife Center Patient of the Week: Great Horned Owl

West Nile Virus impacts wildlife, humans, and domestic animals.

This adult Great Horned Owl was found on the ground, unable to stand, disoriented, and quiet. These neurologic displays are signs of West Nile Virus (WNV), a mosquito-borne virus that can be lethal in a variety of species including birds, humans, and horses.

Given its primary route of transmission, most WNV cases are seen when mosquito activity is at its peak, summer through early fall.

This virus has a high mortality rate in corvids (crows and jays) and raptors (especially Great Horned Owls and Red-tailed Hawks). Typical signs of WNV including incoordination, tremors, and lethargy.

In the past few weeks, we have admitted multiple cases from the Ashburn Farm area of Loudoun County, VA that were confirmed positive via laboratory testing.

This owl is from a bit further west in Loudoun County and we are still awaiting WNV test results.

WNV is an excellent example of the importance of wildlife hospitals in One Health. Many diseases, including WNV, impact humans, wildlife, domestic animals, and the environment. This viral disease was first seen in humans in the U.S. in 1999 in New York City. Since then, it has spread across the country and impacts primarily birds, horses, and humans (horses and some birds, including our educational ambassadors, are lucky enough to have a vaccine). Most humans that contract WNV do not show any signs.

Prevent mosquito breeding by regularly emptying vessels that collect water in your yard including pots, buckets, bird baths, and more. These should be dumped and scrubbed out at least weekly.

Use screens on windows and doors (and repair holes promptly) to prevent mosquito entry into homes. Wear long sleeves and use mosquito repellent when engaging in outdoor activities, especially around dusk.

For horses, please ensure they receive their WNV vaccine as it is the best form of prevention. Sadly, there is no vaccine for humans.

Most avian WNV cases exhibit general signs of lethargy and incoordination.

If you see a raptor or a crow that is quiet and fluffed, down and unable to fly, or having trouble standing properly, especially this time of year, this is a suspicious case.

Tremors, incoordination, and even seizures may also be seen. Please contact us or your local rehabilitator right away if you are seeing signs like this in a bird.

This patient is currently eating well in care and we are hopeful that this bird will recover, but WNV typically has a poor prognosis.

Learn more about preventing West Nile Virus.

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