DEAR DR. GOTT: I heard on television about what appears to be an epidemic of West Nile virus. Other than knowing that it comes from mosquito bites, I am really in the dark on the subject. I live in a wooded area that is relatively damp so the subject has me most concerned. What can you tell me about it?
DEAR READER: West Nile virus goes back to 1937 in eastern Africa but was only recognized in the United States and specifically New York during the summer of 1999. However, I must admit things appear to have ratcheted up recently.
Forty-three states have reported the virus so far this year, with the majority of cases being in the southern states of Texas, Mississippi and Louisiana. Other states that pop up on the radar with rather heavy statistics include Oklahoma, South Dakota and California.
This virus, known as a flavivirus, is believed to be spread when a mosquito bites an infected bird and, in turn, bites a person. Transmission can also occur through a blood transfusion or from organ transplant. An infected mother can also spread the virus to a nursing baby. It is during the months of August and early September that the mosquito carries the greatest amount of virus. The times between dusk to dawn appear to be peak biting times for many mosquitoes so when possible, avoid outdoor activity unless properly protected. Keep in mind that people are bitten every day of the year without viral transmission so this is not to be a cause for general panic. Further, as one might expect, the risk of disease decreases as fall and colder weather arrives and the mosquito population declines.
Symptoms of the disorder include fever, headache, loss of appetite, abdominal pain, nausea, diarrhea, swollen lymph nodes and rash. In actuality, the signs mimic those of other viral infections. According to the Centers for Disease Control (CDC), 80% of infected individuals have such a mild case that it is noticed. Only one in 150 infected people will require hospitalization.
Diagnosis is made via several methods. The most rapid method uses polymerase chain reaction (PCR) testing. Another method is through serology testing that uses blood or cerebral spinal fluid samples to look for antibodies against the virus. A lumbar puncture and cerebrospinal fluid testing will likely be ordered for verification.
Because the illness is viral and not bacterial, antibiotics will not treat West Nile virus. On the upside, healthy individuals usually will not develop serious illness if bitten by an infected mosquito. Toward prevention, the best way to avoid infection is by spraying an repellent containing DEET, picaridin or oil of lemon eucalyptus on shoes and clothing,wearing long pants and long-sleeved shirts when out of doors. Mosquitoes lay their eggs in standing, stagnant water so it is important to drain any pools of standing water such as found in bird baths, trash bin tops, barrels, and plant bases. Another thing we don’t consider right away is holes in our window screens that can allow insects to enter. This might be a good time to make repairs to those screens you’ve been meaning to get at.
An indication of the virus in an area is dead birds. I am not implying that all dead birds have been infected with West Nile because there are countless other reasons for this to occur but to date, over 130 species of birds are known by the CDC to have been infected. One way citizens can assist is to advise their local or state agencies of sightings so they can be properly investigated.
