West Nile


Q: What is the West Nile virus?
A: The West Nile virus belongs to a group of viruses known to cause encephalitis, a potentially fatal inflammation of the brain and spinal cord. The West Nile virus is known to affect horses, birds and humans. It has also been confirmed in sheep, goats, dogs, and squirrels.

Q: How does the virus spread?
A: The virus is spread by mosquitoes from infected birds and animals to other birds and animals. West Nile has been identified in 138 species of birds, with blue jays and crows seeming to be especially susceptible. There are no known cases of transmission from person to person or from birds or mammals to humans. There was, however, a report of the virus being spread through a blood transfusion.

Q: Where is the virus found?
A: The virus was discovered in Africa decades ago, and was first detected in North America in 1999 during an outbreak in New York. Since then, West Nile infections have been confirmed across much of the eastern, southern, and Midwestern United States.

FAQs about West Nile Virus In Raptors

Q. Have there been any cases of West Nile virus in raptors?
A: Yes. West Nile virus had caused death in raptors in many parts of the United States, most since July 2002.

Q: Has the Raptor Center treated birds suffering from West Nile virus?
A: Yes. Between August and October 2002, the Raptor Center admitted 70 birds suspected of having the West Nile virus. About 60 of those died.

Q: What are the symptoms of West Nile virus in raptors?
A: There seem to be three phases, specifically --

Phase 1: Depression, anorexia, weight loss (in proportion to duration of anorexia), sleeping, pinching off blood feathers. Elevated white cell count.

Phase 2: In addition to the above, head tremors, green urates (indicating liver necrosis), mental dullness/central blindness and general lack of awareness of surroundings, ataxia (clumsiness), weakness in legs.

Phase 3: More severe tremors, seizures.

Q: Is there any treatment for West Nile virus in raptors? What is the bird's prognosis at each stage?
A: There is no prescribed treatment. But supportive care can be provided, and it is possible for birds to recover. In general, the likelihood of recovery depends on what phase the bird is in. Phase 1 birds respond reasonably well to supportive care. Once they reach Phase 2, some birds respond to supportive care, but others do not and proceed to Phase 3. Complete recovery is uncertain. Birds suffering from the severe tremors and seizures characteristic of Phase 3 are close to death. Intervention is probably not going to alter the course.

Q: How can birds be protected from West Nile virus? Is there a vaccine?
A: There is a vaccine for horses that can be used in birds, but we don?t know how well it works for birds. Until an avian vaccine is developed, the best way to prevent West Nile virus in birds is by protecting them from mosquito bites.

Q: What should I do if I find a dead raptor or other bird?
A: In Minnesota, call the Minnesota Department of Health at 1-800-657-3903. If you have a raptor that for some reason is not accepted by the Minnesota Department of Health, call the Raptor Center at 612-624-4745. Minimize any handling of the dead bird. Wear gloves if possible, place the bird in a sealable plastic bag such as a Ziplock, and freeze. Wash hands thoroughly after handling.

Outside Minnesota, contact the Department of Health in your state.

Other resources Include:

  • Cornell University Diagnostic Laboratory (607-253-3900), which will accept birds from zoos and other settings where the birds are "life-time" captives (education center birds, falconry birds) for West Nile virus analysis. If a full necropsy is desired, you should contact a diagnostic laboratory.
  • The USGS Wildlife Health Lab in Madison, Wis., which will accept dead wild birds or those that have been in captivity less than 24 hours and have not been treated with atropine, dexamethazone, or other drugs.

In both cases, the receiving laboratories will pay shipping/mailing costs.