The CDC has reported that infections with West Nile Virus (WNV) have hit a record high, with 1100 documented human infections in 38 states so far this year (including 21 cases in my home state, Georgia.) And with a soggy GulfCoast, things are going to get worse before they get better.
WNV was first found in Africa in the 1940s, and spread to the US in 1999. It has since become the most common cause of mosquito-born illness here. About 80% of infections are entirely asymptomatic—meaning you wouldn’t even know if you were infected. Almost all of the remaining infections cause a relatively mild, flu-like illness called West Nile Fever, with symptoms like fever, headaches, body aches, sometimes nausea and vomiting, and more rarely swollen lymph nodes and rash. The rarest illness occurs when the virus invades the brain, causing West Nile Encephalitis in about 1 in 150 infected people. Symptoms can then include disorientation, seizures, coma, paralysis, and death. Older people are much more likely to have severe cases of WNV infection.
Almost all cases of WNV infection are transmitted by mosquito bites, and the best way to prevent exposure is to avoid mosquitoes:
- Avoid outdoor activity at dusk and dawn, when mosquitoes are most likely to bite.
- Wear long sleeved shirts and pants to keep skin covered.
- Cover any exposed skin with an effective mosquito repellent. The best one is DEET, which is recommended for anyone over 2 months of age. Children should use a product with not more than 30% DEET. Other repellants such as picaridin and oil of lemon eucalyptus might also work fairly well, though other “herbal” types of products don’t work at all.
- Prevent mosquitoes from breeding by draining any containers of water, like clogged gutters or buckets.
Mild symptoms of WNV infection such as fever and aches are best treated with rest, extra fluids, and fever-reducing medicine. Anyone with neurologic symptoms should seek medical care immediately. Infected individuals do not need to be isolated—WNV is not contagious from person to person.
As a side note: once influenza season begins, flu infections and WNV infections will often seem very similar. Protect yourself from flu and from WNV worry by getting a flu vaccine soon.
This blog was originally posted on The Pediatric Insider
© 2012 Roy Benaroch, MD
