News Release: West Nile Virus Identified in Missouri Bird

Missouri Department of Health and Senior Services
P.O. Box 570, Jefferson City, Mo. 65102

For Immediate Release:
July 17, 2002

Contact:
Dr. Howard Pue
Section of Communicable Disease Control and Veterinary Public Health
573/751-6113

West Nile Virus Identified in Missouri Bird; No Human Cases Reported

West Nile virus has been identified in one blue jay that was found dead in Stoddard County in early July. Late yesterday the Veterinary Medical Diagnostic Laboratory, Columbia, Missouri, notified the Missouri Department of Health and Senior Services that the bird tested positive. To date, no laboratory-confirmed human cases of West Nile virus have been reported.

"This is not a surprise to us," said Dr. Howard Pue, chief of the department's Section of Communicable Disease Control and Veterinary Public Health. "We already knew it was in the eastern part of the state, since a number of dead crows were found in the St. Louis area last fall. Also, positive birds have been found this year in states immediately to the east of Missouri, including Illinois, Kentucky, and Tennessee. Missouri has been conducting ongoing surveillance and will continue to monitor the occurrence of WNV and provide public health information."

"Residents should not panic at this news," continued Dr. Pue. "Although West Nile virus is relatively new to our state, there are a number of other mosquito-transmitted illnesses that have posed a risk to Missourians for many years. We need to be aware of these potential threats and take appropriate protective measures."

There are a number of simple steps that residents can take to minimize the risk of contracting diseases transmitted by mosquitoes. When possible, avoid outdoor activity at dusk and dawn (most active feeding times for mosquitoes). If you do go outside during these times, consider using insect repellent. Repellent may be applied to clothing and exposed skin. Label precautions should always be strictly followed, especially when repellents are applied to young children. It also helps to wear long sleeve shirts and pants when outdoors to protect the skin. Other precautions include mosquito proofing of homes by ensuring doors and windows have screens. Standing water that can serve as mosquito-breeding habitat should be eliminated.

Several mosquitoborne diseases, such as St. Louis encephalitis, occur occasionally in Missouri, but West Nile encephalitis has been the most publicized recently. West Nile virus was first discovered in the United States in New York City in 1999 and spread to most northeastern states by the end of 2000. During 2001, the virus spread along the Atlantic seaboard and Gulf states and invaded the Midwest.

West Nile virus, like most mosquitoborne viruses, is found in wild and domestic birds. When a mosquito feeds on an infected bird, it can pick up the virus and transmit it to other noninfected birds. Occasionally, infective mosquitoes will feed on mammals such as horses, dogs, cats, and humans, and transmit the virus to them.

Most people infected with the West Nile virus do not develop any symptoms. Sometimes, though, mild illness results 1 to 2 weeks after exposure with symptoms such as fever, headache, body aches, skin rash, and swollen lymph nodes. Less than one percent of infected people may develop a serious illness that includes encephalitis (inflammation of the brain). These persons might experience headache, high fever, neck stiffness, disorientation, convulsions, and muscle weakness. Infection may prove
fatal, especially among the elderly, in a small number of those who develop encephalitis. West Nile virus is not transmitted directly from birds to humans nor from person-to-person.

Medical care should be sought as soon as possible for persons who have symptoms suggesting severe illness. There is no specific treatment for West Nile infection or vaccine to prevent it. Treatment of severe illnesses includes hospitalization, use of intravenous fluids and nutrition, respiratory support, prevention of secondary infections, and good nursing care.

Hunters should follow the usual precautions when handling wild animals. They should wear gloves when handling and cleaning animals to prevent blood exposure to bare hands and meat should be cooked thoroughly.

People who observe an unusual number of dead birds, especially crows and blue jays, are encouraged to report the incident to their city or county health department. Health officials will determine whether the event should be investigated and whether bird specimens should be submitted to a laboratory for testing.

There are many things that can kill birds besides this virus, and therefore not all dead-bird sightings are investigated. However, some bird species such as crows and blue jays are especially susceptible to infection by this virus.

For more information on West Nile virus, contact your local health department or the Department of Health and Senior Services at 1-800/392-0272 or 573/751-6113. Attached is a fact sheet on West Nile virus. For more information, go to the Missouri Department of Health and Senior Services web site at www.dhss.state.mo.us.

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West Nile Virus Fact Sheet

What is West Nile virus?
The West Nile virus is transmitted by mosquitoes to birds, various animals, and humans. Most persons infected with this virus show no symptoms, although occasional infections can result in serious illness and even death.

Where did West Nile virus come from?
West Nile virus has been commonly found in humans, birds, and other animals in Africa, Eastern Europe, Western Asia, and the Middle East, but until 1999 had not previously been documented in the Western Hemisphere. The U.S. viral strain is most closely related genetically to strains found in the Middle East.

What are the symptoms of West Nile virus infection?
Most people infected with this virus do not have any symptoms. Some people experience a mild illness characterized by slight fever, headache, body aches, skin rash, and swollen lymph nodes. More severe illness can include encephalitis (inflammation of the brain) and is marked by a rapid onset of a high fever, head and body aches, neck stiffness, muscle weakness, disorientation, coma, tremors, convulsions, and in the most severe cases,death.

How soon after exposure do symptoms appear?
Symptoms usually appear 3 to 15 days after exposure.

What if I am pregnant?
There is no evidence that pregnant women are at increased risk due to West Nile virus infection.

How do people get West Nile virus?
The West Nile virus, like most mosquitoborne viruses, is found in wild and domestic birds. When a mosquito feeds on an infected bird, it can pick up the virus and transmit it to other, noninfected birds. Occasionally, infective mosquitoes will feed on mammals such as horses, dogs, cats, and humans, and transmit the virus to them.

If I live in an area where birds or mosquitoes with West Nile virus have been reported and a mosquito bites me, am I likely to get sick?
No, even in areas where mosquitoes do carry the virus, very few mosquitoes-much less than 1%-are infected. If the mosquito is infected, less than 1% of people who get bitten and become infected will get severely ill. The chances you will become severely ill from any one mosquito bite are extremely small.

Can I get West Nile virus directly from birds?
There is no evidence that a person can get the virus from handling live or dead infected birds. However, persons should avoid barehanded contact when handling any dead animals and use gloves or double plastic bags to place the carcass in a garbage can.

How can I report a sighting of dead bird(s) in my area?
Contact your local or state health department if you observe dead birds, particularly crows and blue jays. Health officials will determine whether the event should be investigated and whether bird specimens should be submitted to a laboratory for testing.

Can West Nile virus be spread from person-to-person?
West Nile virus infection is not transmitted from person to person. For example, you cannot get West Nile virus from touching or kissing a person who has the disease, or from a health care worker who has treated someone with the disease.

How can I protect myself from West Nile virus?
It is not necessary to limit any outdoor activities. However, you can and should try to reduce your risk of being bitten by mosquitoes. Mosquitoes are most active at dawn and dusk. Reducing the mosquito population around your home and property can be accomplished by eliminating standing water:

• Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers.
  
• Remove all discarded tires on your property. Used tires are very significant mosquito breeding sites.
  
• Drill holes in the bottoms of recycling containers that are kept outdoors.
  
• Make sure roof gutters drain properly, and clean clogged gutters in the spring and fall.
  
• Turn over plastic wading pools and wheelbarrows when not in use.
  
• Change the water in birdbaths at least weekly.
  
• Clean vegetation and debris from edges of ponds.
  
• Clean and chlorinate swimming pools, outdoor saunas, and hot tubs.
  
• Drain water from pool covers.
  
• Use landscaping to eliminate standing water that collects on your property.

In addition to reducing standing water in your yard, make sure all windows and doors have screens, and that all screens are in good repair. If West Nile virus is found in your area:

• Wear long-sleeved shirts and long pants whenever you are outdoors.
  
• Spray clothing with repellents containing permethrin or DEET since mosquitoes may bite through thin clothing. Apply insect repellent sparingly to exposed skin. An effective repellent will contain 35% DEET (N,N-diethyl-meta-toluamide). DEET in high concentrations (greater than 35%) provides no additional protection. Repellents may irritate the eyes and mouth, so avoid applying repellent to the hands of children. Whenever you use an insecticide or insect repellent, be sure to read and follow the manufacturer's DIRECTIONS FOR USE, as printed on the product.

What should hunters do to protect themselves against West Nile virus?
Hunters should follow the usual precautions when handling wild animals. They should wear gloves when handling and cleaning animals to prevent blood exposure to bare hands and meat should be cooked thoroughly. If hunters anticipate being exposed to mosquitoes, they should apply insect repellents to clothing and skin according to label instructions.

How is West Nile virus diagnosed?
If you or your family members develop symptoms such as high fever, confusion, muscle weakness, and severe headache, you should see your health care provider immediately. Your health care provider will assess your risk for West Nile virus infection. If you are determined to be at high risk, your provider will draw a blood sample and send it to a laboratory for confirmation.

What is the treatment?
There is no specific treatment for viral infections, other than to treat the symptoms and provide supportive care. In more severe cases, intensive supportive therapy is indicated, often involving hospitalization, intravenous fluids and nutrition, respiratory support, prevention of secondary infections, and good nursing care. Elderly persons are at highest risk for developing severe illness due to West Nile viral infection, so these individuals should promptly seek medical care if infection is suspected.

Is there a West Nile virus vaccine for humans?
No, but several companies are working towards developing a vaccine.

Missouri Department of Health and Senior Services
Section of Communicable Disease Control and Veterinary Public Health
Telephone (573) 751-6113

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