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A conversation on West Nile virus and its recent California surge

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Ebola isn't the only virus commanding media attention: West Nile virus, now in its 15th year in the United States, may be surging to unprecedented levels in California, fueled in part by the state's earth-parching drought.

It's a big deal elsewhere as well, with parts of Texas, Louisiana and Midwestern states like Nebraska are also being hit. But California - and its 237 cases as reported by the CDC -  has taken the lead, in part because the drought brings birds and mosquito together at the scarce sources of water, according to reports by the Wall Street Journal and San Francisco's NPR-affiliate KQED. Some regions, including a few communities close to Stanford, are now spraying for the mosquitoes.

I recently chatted with infectious disease expert Lucy Tompkins, MD, PhD, about the disease and how to prevent it. (Tompkins, a fly fisherwoman, knows quite a bit about mosquitoes).

What are the symptoms of West Nile?

The majority of people who get bitten don't have any symptoms. About 20 percent of those bitten develop what is called West Nile fever with a fever, aches, fatigue, maybe a headache and sometimes a rash. It was previously felt this was completely benign but there may be long-term effects. Less than one percent are  the serious  cases with involvement of the brain and nervous system, which has a high mortality rate. That's particularly common in people who are immunosuppressed due to transplants or high use of prednisone or even to those over 50 years. It can be a very disabling infection.

What can people do to protect themselves?

Reduce standing water such as in bird baths and wear protective clothing with long sleeves, long pants and socks covering your pants. Use insect repellents containing DEET - not low-potency insecticides. If possible, avoid being out during the times of day mosquitoes are active such as early in the morning and at sunset. It's all about prevention.

Why isn't there a vaccine for West Nile?

The chances of any one person getting West Nile are pretty remote. There's no market, honestly. There's a much bigger demand in the veterinary market for a vaccine like this. There is a vaccine for horses - West Nile can be fatal in horses. It also affects dogs and cats. There are some experimental treatments - last year at Stanford we gave a patient an experimental treatment and he awoke from a coma.

Do you expect the virus to continue spreading?

It's hard to predict from year to year what communities will be affected. It all depends on what happens in the environment. The best information is available at the CDC.

Becky Bach is a former park ranger who now spends her time writing about science or practicing yoga. She is a science-writing intern in the Office of Communications and Public Affairs.

Previously: Should local residents be worried about West Nile virus?, Image of the Week: West Nile virus and Close encounters: How we're rubbing up against pathogen-packing pests
Photo by: CulexNil

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