Don't Get Bugged This Summer

An infectious-disease pro tells how to protect yourself from harmful bites

Summer is almost here, and with it comes an increased risk of infectious disease contracted from insect bites or while traveling. Potentially deadly viruses such as avian flu, SARS, and Marburg have emerged abroad, while mosquito- and tick-borne ailments such as West Nile virus, Lyme disease, and Rocky Mountain spotted fever are prevalent in the U.S.

Dr. Scott Weaver, director for tropical and emerging infectious diseases at the University of Texas Medical Branch in Galveston, keeps tabs on such threats. Houston correspondent Kate Murphy talked with him about how you can protect yourself.

What diseases most concern you now?

West Nile is the big one we're looking at because of its prevalence throughout the U.S. A number of researchers are also studying tick-borne bacterial diseases. These diseases are difficult to diagnose clinically and can be life-threatening.

Why are they difficult to diagnose?

Say you go to your physician because you have nonspecific flu-like symptoms. If you told the doctor you were doing outdoor activities and had got bitten by a tick, the doctor might say, "Aha!" and immediately treat you with antibiotics. The problem is, a lot of times people don't make the connection, and physicians don't ask. So the physician might assume you have a virus and not treat you with antibiotics.

West Nile virus also produces flu-like, nonspecific symptoms that can be mistaken for other diseases. Even with early diagnosis, there really is no effective treatment, but there are ways to mitigate the seriousness.

Are there blood tests you can ask for to get a definitive diagnosis?

Most of the blood tests for tick-borne diseases measure antibodies, and when you become infected, it takes a few days before you form antibodies. So those tests aren't the fastest ways to detect infection. The newer techniques are mostly ways of detecting the presence of the genes of the bacterial organisms in your blood, which is a lot faster than waiting for antibodies to develop. But these tests aren't commercially available yet. For West Nile, some good laboratory tests can detect the disease almost immediately.

What preventive measures do you recommend?

Wear boots, and tuck your pants inside your socks so ticks won't have access to your skin as easily. Typically, ticks wait on vegetation and jump on your shoes, socks, or pants when you walk by. They crawl around looking for exposed skin, but they are likely to jump off if they have to climb very far. The mosquitoes that carry West Nile usually bite in the early evening, so if you are going outdoors, wear repellent and double layers of clothing for protection.

Are there disease hot spots to avoid?

I don't think it would be a good idea to go to Angola right now because of an outbreak of Marburg virus. But it's certainly not a reason to stay away from all of Africa. Bird flu is more of a risk, and that would be for people who travel to Asia. The majority of people who get infected are the ones who handle the birds directly. Although it's always interesting to go to markets, you might want to avoid them, and certainly you'd want to stay away from the birds for sale there. The SARS virus has also been a problem in Asia, but it comes from small mammals, so far as we understand. SARS outbreaks are pretty much wintertime events.

What precautions should you take before traveling?

Go to your primary-care doctor or a travel clinic to get the vaccines and medicines you need to protect you wherever you are going. For example, yellow fever is prevalent in Latin America. Even though there's an effective vaccine, a lot of people don't bother to get it before they go to, say, Brazil or Peru -- and end up contracting a life-threatening disease.

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