West Nile virus is a flavivirus commonly found in Africa, West Asia, and the Middle East. It is closely related to St. Louis encephalitis virus found in the United States. The virus can infect humans, birds, mosquitoes, horses and some other mammals. West Nile fever is a case of mild disease in people, characterized by flu like symptoms. West Nile fever typically lasts only a few days and does not appear to cause any long-term health effects.

West Nile fever is an infection from WNV resulting in mild flu-like symptoms, typically lasting only a few days and does not cause long-term health problems. West Nile encephalitis is a severe illness with symptoms including headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis.

West Nile virus, which causes West Nile fever, encephalitis and meningitis, is a mosquito-borne virus that first appeared in the United States in 1999. After being found in bird populations in the metropolitan New York area, it has since spread across the United States. As of fall 2006, six birds and one horse with West Nile Virus have been reported in King County.

According to the most recent reports that we have heard, one llama was suspected of having had West Nile Virus, but it was not confirmed. There has been a confirmed case in an alpaca.

When someone is infected with West Nile virus (WNV) they will typically have one of three outcomes: No symptoms (most likely), West Nile fever (WNF in about 20% of people) or severe West Nile disease, such as meningitis or encephalitis (less than 1% of those who get infected). If you develop a high fever with severe headache, consult your health care provider. West Nile fever is characterized by symptoms such as fever, body aches, headache and sometimes swollen lymph glands and rash.

If you develop signs of encephalitis, with fever, muscle weakness, and confusion, you should seek medical care immediately.

There is no specific therapy. In more severe cases, intensive supportive therapy is indicated, i.e. hospitalization, intravenous (IV) fluids and nutrition, airway management, ventilator support if needed, prevention of secondary infections (pneumonia, urinary tract, etc.), and good nursing care.

No, People become infected by the bite of a mosquito infected with West Nile virus. There is no evidence that a person can get the virus from handling live or dead infected birds. However, you should avoid using your bare hands when handling any dead animals.

this time, there is no vaccine approved for llamas against West Nile Virus. We hope that by the spring, when the mosquitos are out in force again, a vaccine will have been developed. We will keep you posted as we learn more.

In horses that do become clinically ill, the virus infects the central nervous systems and causes symptoms of encephalitis. Clinical signs can include: loss of appetite, depression, fever, weakness of hind limbs, paralysis of hind limbs, impaired vision, ataxia, head pressing, aimless wandering, convulsions, inability to swallow, circling, hyperexcitability or coma.

There is no specific treatment for West Nile virus other than supportive veterinary care standard for animals infected with a viral agent. Data suggest that most horses do recover from the infection.

All residents of areas where virus activity has been identified are at risk of getting West Nile encephalitis; persons older than 50 years have the highest risk of severe disease. There have been numerous cases of humans being infected with the virus. Centers for Disease Control West Nile Virus Home Page

No symptoms in most people - Approximately 80% of people who are infected with WNV will not show any symptoms at all. Mild symptoms in some people - Up to 20% of the people who become infected will display mild symptoms, including fever, headache, body ache, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms typically last a few days. Serious symptoms in a few people - About one in 150 people infected with WNV will develop severe illness.

WNV is spread to humans by the bite of an infected mosquito. A mosquito becomes infected by biting a bird that carries the virus. You or your child cannot get WNV from a person who has the disease. WNV is not spread by person-to-person contact such as touching, kissing, or caring for someone who is infected.