West Nile Virus

Last week the first reported death in 2012 from West Nile Virus (WNV) was reported in Nassau County (www.nassaucountyny.gov/agencies/Health/index.html ).  Although this was one of only two cases reported in Nassau this year, the infection has received much attention from the media this summer, particularly in Texas where the total number of cases in approaching 900.

First discovered in Uganda in 1937, WNV is primarily an infection of birds, but one that can be acquired by humans after being bitten by a mosquito that previously bit a bird. It was first recognized in New York City in 1999, and soon after was seen on Long Island.  IN 2010, 3 Nassau residents and 3 Suffolk residents died of WNV infection.

The majority of patients infected with WNV are asymptomatic. The virus enters their body through a mosquito bite, is recognized by the immune system, and is eliminated before an infection can take hold. However, about 1 in 5 patients develop West Nile Fever. This is a flu-like illness characterized by fever, headache, muscle pain and decreased appetite.  Unlike the flu, a rash is common. The acute illness lasts up to a week, but lingering fatigue may persist for a month or longer.

Less than 1% of people will develop severe disease, with involvement of the nervous system. After initial headache and fever, confusions, seizures, paralysis and coma may ensue. Less than 40% of this group will recover fully. At particular risk for serious infections are pregnant and nursing women, people over 50 (the patient who died last week was an octogenarian) and patients with a weakened immune system.

There is no specific treatment for WNV infection, so basic prevention of mosquito bites during summer months is the best approach. Standing water serves as a mosquito breeding ground, so buckets, small wading pools, bird baths, etc must be drained. This is a good time to inspect screens to make sure they are intact and not vulnerable to penetration.  Mosquitoes are most active at dawn and dusk, so long pants and long sleeves are protective. If you spot a dead bird in your neighborhood, contact the health department to get advice.

Bug zappers, sonic devices and mosquito traps have not been shown to be useful. On the other hand, repellents with DEET or picardin are very effective. Oil of lemon eucalyptus has also proven to be protective. In addition, certain products which contain permethrin can be applies to clothes, shoes, and camping equipment. With all of these, be careful and follow the product instructions.

For more information please go to http://www.uptodate.com/contents/patient-information-west-nile-virus-infection?view