West Nile Virus

West Nile virus has been in the news recently and led to many people being concerned.  This disease can be serious, even fatal, but it is relatively uncommon.  No human vaccine is available and protection from mosquito bites is the only prevention available at this time. 

What is the West Nile virus?

 The West Nile virus is a flavivirus that is most commonly found in Africa, West Asia and the Middle East .  The virus can infect humans, birds, mosquitoes, horses and other animals.   It is believed that the virus has been in the United States since 1999.  Most cases occur in the summer and fall. 

  West Nile virus is a potentially serious and even fatal disease.   The virus has killed more than 400 people nationwide since 1999.  However, less than 1 in 1,000 people infected with the West Nile virus will die.  Although the risk of being infected is low, the risk increases for those who spend a lot of time outdoors. 

 How do you catch this virus?

 The virus is spread to humans by the bite of an infected mosquito.  A mosquito becomes infected by feeding on an infected bird.  Rarely, the virus may be spread by blood transfusions, organ transplants, breastfeeding and during pregnancy from mother to baby.    

 Can you catch West Nile virus from another person?

 No, the virus is not spread by person-to-person contact; therefore, you cannot catch this disease from another person.

 Can you catch West Nile virus from a bird?

 Although there is no evidence a person can be infected from handling live or dead infected birds, persons should avoid bare-handed contact when handling any dead animals including birds.    

 How can I protect myself and my family?                          

 The only way to protect your family is to prevent being bitten by mosquitoes.  Although a mosquito may bite at any time, the time of highest risk is dusk and dawn.   Therefore, it is important to wear appropriate clothing (long-sleeved shirts and long pants), stay indoors, place mosquito netting over infant carriers, check window screens, drain sources of standing water, and use insect repellant sprays which contain the active ingredient DEET ( N,N-diethyl-meta-toluamide).

 Insect repellant sprays containing DEET are available in different concentrations.  A higher concentration of DEET just means the repellant will last longer, not that it will provide stronger protection.   DEET products are considered safe to use even on children; although children under 12 years of age should not use concentrations of greater than 30%, and children under 2 years of age should probably not use concentrations greater than 10%.   DEET should not be used on infants under 2 months of age.  The use of combination products with sunscreen is not recommended.  This is because sunscreen needs to be applied repeatedly but DEET products should only be applied once a day. 

 What are the signs and symptoms of West Nile virus?

 About 80% of people who become infected with the West Nile virus will show no symptoms.  Up to 20% will show mild symptoms including headache, body ache and fever ( West Nile fever).  Sometimes there may be a skin rash and/or swollen lymph glands.  Symptoms last for a few days to several weeks, but there will be full recovery. 

 However, about 1 in 150 people will develop a severe illness. Elderly people, and those with a weakened immune system, are most susceptible.   The most serious form of infection causes meningitis (an inflammation of the lining of the brain), and/or encephalitis (an inflammation of the brain); these diseases may be fatal.  Symptoms include severe headache, high fever, confusion and coma. 

 I got bit by a mosquito earlier today and now have a headache.  Could I have West Nile virus?

 This would be unlikely as symptoms do not usually show up for 3 to 15 days after being bitten.  Furthermore, the chance of the mosquito being infected with the West Nile virus is rare.  However, if your headache persists or you develop a fever, confusion, or muscle weakness you must contact your physician immediately.  . 

 I was bitten by a mosquito a week ago and now have a headache and fever.  Can I be tested for the West Nile virus?

 If your physician determines that you are at risk for West Nile virus a blood test can be ordered which looks for the presence of antibodies to the West Nile virus. 

 Is there any treatment for West Nile virus?

 There is no specific treatment available against this virus.  Milder cases do not need any specific medical attention.  Treatment of severe cases requires hospitalization, but is still just supportive with IV fluids, respiratory support and prevention of secondary infections. 

 Since there is no treatment available is there a vaccine available now that will protect my family?

 Although a veterinary vaccine against West Nile virus is available for horses, no human vaccine is currently available.  Two drug companies, Acambis and Hawaii Biotech, are currently testing vaccines against this virus, while another, Chiron, is in the early stages of research.  However, it remains to be seen if a vaccine will be ever be cost effective since the infection is not very common. 

 The veterinary vaccine should not be used in humans.  It has never been studied in humans for safety or effectiveness, and could be harmful or even fatal. 

 Therefore, at this time, the best prevention is to limit your exposure to insect bites with protective clothing and insect repellant sprays containing DEET.