ASK DR LAURO
(If you have questions you would like Dr. Lauro to answer, send them to healthy [email protected])
West Nile Virus: Is It Time To Panic?
This past week the West Nile Virus was finally confirmed in birds and several horses in the State of Utah. Although there have not yet been any human infections in Utah, it is only a matter of time. Utah had been one of the last states to have escaped the infection. With the recent detection of the virus in Utah, it is now obvious that soon the remaining Western States will be infected, and thus the virus detected in every state in the country. With this latest revelation that the virus is now essentially coast to coast, how concerned should we be? How serious an infection is this mosquito-borne virus? What are the symptoms? And who is most likely to get it?
West Nile Virus-The symptoms:
Humans are infected with West Nile Virus through a mosquito bite. Most people who are infected remain asymptomatic. That is to say, there are no symptoms at all. The next group of people who are infected with the virus, which is much smaller in number that the first group, will have a mild illness with symptoms similar to what many call “summer flu.” This is a condition wherein people develop a low-grade fever, muscle aches and pains, fatigue, lack of appetite, and a dull headache.
The final group of infected patients represents a very small percentage of all those infected but they have the most severe form of the disease. This group will have true encephalitis and/or meningitis from the West Nile Virus. These patients have mental confusion, profound lethargy, stiff neck, bad headache, neck pain, intense muscle weakness (and even muscle paralysis similar to polio), and of course, they will also have the other more generalized symptoms such as fatigue, fever and malaise.
Spread of the disease:
Wild birds are the natural host for West Nile Virus. Members of the crow family seem to be more susceptible (Ravens, Jays and Magpies). Horses seem to be also quite susceptible to severe illness. For some unknown reason, cows and cats seem to be naturally resistant while dogs have shown some infection.
Who is most susceptible to the severe form of the disease?
Elderly people and those who are immunocompromised (those whose immune systems are not very strong, such as AIDS patients, patients taking Chemotherapy, etc) are most susceptible to the severe form of the disease. This group also has the highest incidence of mortality from the virus.
Are the numbers of cases still rising?
It seems that the states that were earliest infected a few years ago with West Nile Virus are starting to see stabilization in the incidence of new cases and is some states we are actually seeing declines. This is because the bird population that carries the virus is starting to either die from the disease itself or develop an immune response and natural antibodies. Thus the West Nile Virus is starting to stabilize the in Eastern and Central United States where it was first discovered a few years ago. As the virus spreads out across the country and goes into states where it has not been seen before, we will see the highest incidence of the more severe cases of West Nile Virus. I believe this has been proven by looking at all the recent deaths in Colorado. The far western states that have not seen the disease yet, or where it is just beginning to raise its ugly head, such as Utah, Nevada, Arizona and Oregon, should see a rapid increase in the number of cases, followed within the next few years by stabilization and decline.
How is West Nile Virus infection detected?
If a patient has symptoms of the more severe type of West Nile Virus, then he or she should seek medical attention and be tested by a physician for the virus. This is done through a test of the cerebral spinal fluid through a lumbar puncture. One can also detect the West Nile Virus in the peripheral blood stream through a blood test, but it is not as accurate.
How is West Nile Virus prevented?
Because the virus is introduced in humans through mosquitoes, if one can avoid mosquito bites one should be able to avoid the disease altogether. The best advice for limiting ones exposure to mosquitoes is to limit outdoor activity between the hours of dusk and dawn. That is when mosquitoes seem to be most active and are more likely to bite. If one is going to be outside and active during those times (late in the evening and through the night into the early morning) then mosquito repellant should be worn. The most effective repellants have the chemical DEET in them. There are different strengths available according to how long one expects to be outside and also what ones age is. In younger children we use a much lower strength, so be sure to follow the directions on the product. Wearing long sleeved clothing and pants is also helpful and, of course, trying to limit standing water on ones property, where mosquitoes live and breed, is very helpful.
Can the West Nile Virus be transmitted through blood transfusion?
Recent information tends to confirm that this is the case. Currently there is no blood test to detect the West Nile Virus in donated blood, as the Red Cross is not doing standardized tests yet for this. Therefore the Red Cross asks that donors postpone any donation if they feel ill, especially with the symptoms of West Nile Virus.
Are there are treatments for the West Nile Virus?
At the present time there are no established specific treatments for West Nile Virus There is also no vaccine. There is an anti-viral called Ribavirin that is being investigated, but results are not yet available on its effectiveness. Treatment is therefore supportive, which means severe cases are hospitalized and patients are given medical support to virtually keep them alive until their bodies heal themselves. Remember though, the death rate from West Nile Virus is still extremely low.
My advice then is not to panic, but be vigilant and careful and do take precautions to limit your chance of mosquito bites.
