West Nile Virus (WNV) is a viral disease previously only seen in Africa, Asia and southern Europe. This virus can cause encephalitis, an infection of the brain and spinal cord. In 1999, an unexpected outbreak of WNV occurred in New York City. At least 62 people became seriously ill and seven of those died. Since then, WNV has rapidly spread throughout the state of New York and across the United States. In 2000, 21 cases were reported, including 2 deaths in New York City. In 2001, there were 66 human cases of severe disease and 9 deaths. No reliable estimates are available for the number of cases of West Nile Virus encephalitis that occur worldwide. As of July 10, 2002, there has been 1 reported human case of West Nile virus infection.

The West Nile Virus is spread to people by the bite of an infected mosquito. The principal transmitter of the 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 to 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 directly from another person who has this disease.

Continued spread of this disease among wild birds and mosquitoes is anticipated. In Ohio, state, federal, and local agencies are working together to address the potential health risks of WNV to Ohio families and their animals. Public health officials are looking for WNV in horses, crows, blue jays, and mosquitoes, to monitor WNV activity in Ohio. This surveillance will provide information so that mosquito control efforts and public education can be concentrated in those areas, thereby protecting the people from disease.

No. Mosquitoes are generally considered a nuisance pest, but they occasionally can transmit disease. There are 64 different species of mosquitoes know to occur in Ohio. While most cannot transmit west Nile Virus, several mosquito species common to Ohio are known to be carriers of WNV. Only female mosquitoes bite. They do this to get a blood meal for developing their eggs.

The mosquito that carries WNV typically lay their eggs in stagnant water and water-holding containers. Weeds, tall grass and shrubbery provide an outdoor harborage for adult mosquitoes.

Many mosquitoes are most active two to three hours before and after dusk and again at dawn when the air is calm. This is the time when the females are most likely to bite. However, some species will feed at any time of the day.

Most people have become infected in summer or early fall when mosquitoes are most numerous.

Yes. During the winter months of 2000, health workers in New York City found over-wintering mosquitoes that contained evidence of WNV.

No. During 1999 and 2000, the states reporting WNV activity found many different bird species infected with WNV. However, crows and blue jays appear to be the most susceptible. This observation is not completely understood.

Yes. Other animals have also been found to be infected and have died from WNV. During the year 2000, reports from the Eastern states found WNV infecting 58 horses, two bats, a domestic rabbit, skunk, a cat, gray squirrel and a chipmunk.

No. The virus is not spread by person-to-person contact and there is no evidence that people can get the disease by handling infected animals.

Most people who are bitten by an infected mosquito will demonstrate no signs or symptoms. However, some will experience a mild infection with slight fever, headache, body aches, and sometimes a skin rash or swollen lymph glands. Symptoms usually occur five to 15 days after being bitten by an infected mosquito. A very small number of people will suffer from a severe infection that is marked by a rapid onset of high fever, severe headache, neck stiffness, nausea, or vomiting, confusion, muscle weakness or paralysis, seizures, coma, and, rarely death.

While everyone exposed to a mosquito that carries WNV is susceptible, people at greatest risk are those older than 50. Those who are immune-compromised may also be at greater risk. During the outbreak in New York City in 1999, everyone who died fro WNV infection was 75 years of age or older.

To diagnose a WNV infection, a doctor will need to test either blood or cerebrospinal fluid from a spinal tap for antibodies to the virus. A second test is required two to three weeks later to confirm the diagnosis.

No. There is no specific treatment for West Nile virus infection. While many people will not know they have been exposed, nearly all of those with symptoms will fully recover. However, in some severe cases, hospitalization may be needed. There is no vaccine for WNV. There are no antibiotics or antiviral medications that can be used in the tratment of WNV. All care is supportive.

You can reduce the number of mosquitoes around your home and neighborhood by eliminating places where they lay their eggs. Young mosquitoes are aquatic, and they must have standing water to develop from egg to adult. Her are some simple steps you cant take:

The best way is to avoid being bitten by mosquitoes. Use personal protection while outdoors when mosquitoes are present. These following actions will reduce your chances of being bitten by mosquitoes.

Additional information may be obtained on the Web at www.odh.state.oh.us/ODHPrograms/ZOODIS/ZooMain1.htm and  www.cdc/ncidod/dvbid/westnile