~ provided to us by Danell Adams
West Nile Virus (WNV) Information
Confirmed 2008 West Nile Virus Infections in Orange County ~ last updated: 9/05/08
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West Nile Virus (WNV) is endemic in Orange County and is expected to be a public health concern indefinitely. WNV
first reached Orange County in 2003 when a few dead birds tested positive. In 2004, Orange County had its first human
cases with 64 confirmed human WNV infections. Since 2004, there have continued to be human WNV infections re-
ported each year. Because it is not possible to accurately predict the impact WNV will have on people in Orange
County each year, all residents and visitors are urged to continue to take precautions against WNV infection every
Q. What is West Nile Virus?
A. West Nile virus (WNV) is a virus that is most commonly spread by the bite of an infected mosquito. It affects the
central nervous system and can cause a potentially serious illness with varying symptoms as described below. People
who spend a lot of time outdoors are more likely to be bitten by an infected mosquito, and people older than 50 years of
age are at increased risk for severe disease if bitten by an infected mosquito. In a very small number of cases, WNV
was spread through blood transfusions, organ transplantations, from mother-to-baby (during pregnancy and through
breastfeeding), and through work exposures (animal handling or laboratory). Animals can also be infected with WNV
and certain birds in particular play an important part in the life cycle and spread of the virus although birds do not di-
rectly spread the infection to humans. There is no treatment except supportive care for WNV infection, although experi-
mental therapies are currently being studied. Avoiding mosquito bites is the #1 way to prevent WNV infection.
Q. What are the symptoms of West Nile Virus Infection?
A. Infection occurs in less than 1% of people bitten by an infected mosquito. If infection occurs, symptoms begin 2-14
days after the mosquito bite and include:
No Symptoms in about 80 percent of the people who are infected with WNV.
Mild to Moderate Symptoms in up to 20 percent of the people who become infected. They will display symptoms,
which may include fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a
skin rash on the chest, stomach and back. Symptoms typically last a few days and it is not necessary to seek
medical attention unless there is no improvement, more serious symptoms develop, or you are pregnant or breast-
Serious Symptoms in about one in 150 people infected with WNV. These can include high fever, headache, neck
stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paraly-
sis. These symptoms may last several weeks, and some neurological effects may be permanent.
How to Reduce Your West Nile Virus Risk
Avoid Mosquito Bites ~~
Apply insect repellent containing DEET (N,N-diethyl-metatoluamide), picaridin, oil of lemon eucalyptus, or IR3535
(3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester) to exposed skin whenever you go outdoors. Be sure to fol-
low the product directions for use.
Wear long-sleeves, long pants and socks when outdoors, whenever possible. Spray thin clothes with repellant to
provide extra protection but do not spray repellants containing permethrin directly on the skin and do not spray
DEET under the clothing.
Avoid outdoor activities from dusk to dawn, which are peak mosquito biting times. If you must go outdoors in the
evening and early morning, be sure to use repellant and protective clothing as described above.
Mosquito-Proof Your Home
Drain standing water (which serve as mosquito breeding sites) around your home. This includes empty containers,
flowerpots, bird baths, and pet dishes.
Install or repair tight fitting screens on your windows and doors to keep the mosquitoes out.
Help Your Community
Arrange or participate in neighborhood clean-up days to pick up empty containers, tires, and other standing water
sources to eliminate mosquito-breeding sites in your community.
Report dead birds (if they have been dead less than 24 hours) to the State of California 1-877-WNV-BIRD. Some
birds may be tested for WNV infection. Dead birds may indicate that WNV is circulating in the area.
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