Ohio State University Extension Fact Sheet

Veterinary Preventive Medicine

1900 Coffey Road, Columbus, OH 43210

Frequently Asked Questions About Birds and West Nile Virus

WNV-1000-06

What Is West Nile Virus?

West Nile Virus (WNV) is a viral disease previously seen only in Africa, Asia, and southern Europe. This virus can cause encephalitis or meningitis, infection of the brain and the spinal cord or their protective covering. For the past six years, WNV has caused disease in the United States.

In 1999, at least 62 people became seriously ill, and seven of those died. Since then, WNV has rapidly spread throughout North America. During the year 2000, 21 human cases of WNV encephalitis were reported in the United States, with two deaths. In 2001 there were 56 cases with seven deaths.

In 2002, 4,156 human cases of WNV encephalitis or WNV fever were reported, with 284 fatalities. During 2003, almost 10,000 human cases of WNV encephalitis and fever were reported from 46 states, with 208 fatalities. In 2004, there were some 2,500 human cases with 87 deaths, with the cases occurring primarily in the western United States. In 2005, there were 2,800 cases with 105 deaths.

In Ohio in 2005, WNV was reported in birds, mosquitoes, humans, and horses. There were 61 human and 15 horse cases identified. It is expected that WNV will continue to be a disease threat in 2006.

West Nile Virus is spread to people by the bite of an infected mosquito. The principal transmitter of West Nile Virus is the Northern House Mosquito (Culex pipiens). Mosquitoes first become exposed to the virus when they feed on birds that are infected with WNV. Once the mosquito is infected, it may transmit the virus to people or other animals when it bites them. Many birds can be infected with WNV, but crows and blue jays are most likely to die from the infection. Horses, too, are prone to severe WNV infection. People cannot get WNV from another person or a horse that has the disease.

Continued spread of this disease among wild birds and mosquitoes is anticipated. State, federal, and local agencies are working together to address the health risks of WNV to Ohio families and their animals. Public health officials found WNV in many species of birds, mosquitoes, and horses in 44 Ohio counties during 2005. Once this was known, mosquito control efforts were increased in those areas to protect people from the disease.

Reporting Dead Crows

• Q. Why should I report a dead crow or blue jay?
• A. As part of Ohio’s surveillance plan for West Nile Virus, the state departments of agriculture and health are monitoring dead birds in Ohio. Crows and blue jays are related and are especially susceptible to West Nile Virus infection. A dead bird that shows no other sign of injury or reason for death may have died from a WNV infection. Bird deaths have preceded outbreaks of this disease, so birds can be an early warning that WNV is present.


• Q. What should I do if I find a dead bird?
• A. If you find a dead bird, contact your local health department.


• Q. What information do I need to give to the person I talk to?
• A. You’ll be asked for the specific location of the bird, including the address, county, and zip code, and when it was found. We’ll also want to know how many birds you’ve found dead, and if there are any signs of injury. Finally, we’ll ask for your name and telephone number in case we need to get more information from you.


• Q. When will you pick up the bird?
• A. Because of the number of birds that may need to be tested, we won’t be picking up every bird that is reported. You’ll be told if the bird is needed and given further instructions at that time.


• Q. What should I do if I’m told the bird isn’t needed for testing?
• A. If testing is not required, use a shovel or wear gloves and double bag the bird in two plastic bags and dispose of it in the trash.


• Q. Do I risk exposure to West Nile Virus by handling a dead bird?
• A. There is no evidence that West Nile Virus is spread directly from dead birds to humans. However, health professionals advise that bare-handed contact with dead animals should always be avoided. Use a shovel or wear gloves when handling any dead animal.


• Q. How long does it take to test a dead bird for West Nile Virus?
• A. Because birds will be tested based on a predetermined set of priorities, not the date received, it is not possible to provide you with a time frame.


• Q. When will I receive the test results of the bird(s) that I submitted?
• A. As soon as possible. A large number of birds will be tested. For example, in 2003, thousands of birds from 44 states and the District of Columbia were documented as infected with WNV; far more birds were tested but did not carry the disease. Your efforts to report dead birds for testing are a very important part of the West Nile Virus surveillance in your area.


• Q. How will test results be used?
• A. Test results will be used to monitor the occurrence of WNV in towns and cities and to make decisions regarding appropriate control measures. We know that dead birds precede human infections. This gives us time to warn residents and to increase mosquito control in the area.


• Q. If I see a lot of crows roosting in an area, should I be concerned about West Nile Virus?
• A. No. Seeing crows alive and well is a good indication that the virus is not in your area. Dead crows, however, may indicate the presence of the virus and should be reported to your local health department.


• Q. Are crows the only birds affected by West Nile Virus?
• A. No, but crows and their relatives (especially blue jays) are most likely to die. Large numbers of North American crows and other birds were observed becoming ill and dying. Some exotic birds in zoos died. West Nile Virus has been identified in at least 200 species of free ranging and captive birds found dead in the United States. The public reported most of these birds. Wildlife biologists have also found evidence that some healthy birds have been exposed to the West Nile Virus and have survived.


• Q. Are pet birds or poultry at risk for West Nile Virus?
• A. Poultry do not seem to be seriously affected by WNV. Although there is little evidence that pet birds have become ill from the virus, infections without symptoms are possible. It is prudent to protect pet birds from biting mosquitoes.


• Q. Can a dead bird pose a risk to my pet dog or cat?
• A. To date, there is no evidence that a pet having any type of contact with a dead bird, including eating it, will develop WNV. There is evidence that a small number of dogs and cats have been infected with WNV, so you should protect your pet from biting mosquitoes. Eliminate stagnant water around your property — regularly clean bird baths, drain water from old tires, empty water-filled buckets and containers where mosquitoes might breed.

What Is the Status of WNV in Ohio?

WNV was confirmed in Ohio in 2005. Infected mosquitoes, birds, horses, and humans were found in 44 Ohio counties. Therefore, the virus is present throughout the state. Contact your local health department or log on to the web sites listed here for the current status on WNV in Ohio and for more information:

Ohio State University:
prevmed.vet.ohio-state.edu/Extension/WestNile/WNV.htm

Ohio Department of Health:
www.odh.state.oh.us/ODHPrograms/ZOODIS/ZooMain1.htm

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