About West Nile Virus
What is it?
West Nile Virus is a virus commonly found in Africa, West Asia and the Middle East. It is not known how long it has been in the United States, but the Centers for Disease Control and Prevention (CDC) believe the virus probably has been in the eastern United States since early summer 1999. It is closely related to St. Louis encephalitis virus found in the United States. The virus can infect humans, birds, mosquitoes, horses and other animals.
How can I reduce my risk of getting West Nile Virus?
Preventing mosquito bites is the best way to avoid getting the West Nile Virus. Remember the Four Ds: Drain, Dusk/Dawn, Dress and DEET.
DRAIN standing water in your yard and neighborhood. Standing water can be found in swimming pools that are not kept clean, ponds, pet watering dishes, birdbaths, potted plants, old tires, empty containers, toys and clogged rain gutters.
DUSK/DAWN are the times of day you should stay indoors when mosquitoes are most active.
DRESS in long-sleeved shirts and wear pants when you are outside. Spray thin clothing with insect repellent.
DEET (N, N-diethyl-m-toluamide) is an ingredient to look for in your insect repellent.
What are the symptoms?
Most people infected with the West Nile Virus will not have any signs of illness. Twenty percent of people who become infected will have mild symptoms such as fever, headache, body aches and occasionally a skin rash on the trunk of the body and swollen lymph glands.
The symptoms of severe infection (West Nile encephalitis or meningitis) include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis. Only about one out of 150 people infected with West Nile Virus will develop this more severe form of disease.
The incubation period of West Nile Virus in humans is three to 14 days. Symptoms of mild disease may last a few days. Symptoms of severe disease may last several weeks, although neurological effects may be permanent. Rarely, death can occur.
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How is it spread?
West Nile Virus is spread by the bite of an infected mosquito and can infect people, horses, many types of birds and other animals. There is no evidence that West Nile Virus can be spread from person to person or from animal to person, except by mosquito bite.
Who is at risk for West Nile Virus?
People over 50 years of age have the highest risk of severe disease. It is not known if people with weakened immune systems are at an increased risk for West Nile Virus.
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How is West Nile Virus treated?
There is no specific treatment for West Nile Virus infection. In severe cases, intensive supportive therapies are indicated, such intravenous fluids and medicine to control fever or pain. Antibiotics may be given for any secondary bacterial infection.
Can I be vaccinated for West Nile Virus?
Currently there is no vaccine for West Nile Virus, but several companies are working toward developing a vaccine.
Is this a seasonal virus?
West Nile encephalitis cases usually occur in the late summer or early fall. However, Texas has a variety of climates; and when temperatures are mild, West Nile Virus can be transmitted year round. It is best to try to protect yourself all year.
How likely am I to be bitten by an infected mosquito?
Less than one percent of those bitten by infected mosquitoes become severely ill. If you have any of the symptoms, contact your doctor immediately.