One mosquito bite can paralyze you for life. But hey, why worry about it?

That attitude is frustrating public health officials worried about the spread of West Nile virus and other mosquito-borne diseases.

Mid-July means the U.S. is entering peak West Nile virus season. Yet most Americans still aren't doing enough to fight the bite, says behavioral scientist Emily Zielinski-Gutierrez, DrPH, at the CDC's Division of Vector-Borne Diseases in Ft. Collins, Colo.

"It really comes down to the fact that people are not enough afraid of West Nile virus to do something about it," Zielinski-Gutierrez tells WebMD. "People are actively choosing not to use mosquito repellent."

Read WebMD's "Bug Spray, Sunscreen May Not Be a Good Mix"

Americans on West Nile Virus: 'What, Me Worry?'

The active ingredient in most bug repellents is a chemical called DEET. Are we more afraid of DEET than of mosquitoes? Not most of us. In fact, a recent CDC survey shows that only half of Americans even know what DEET is.

The survey, conducted in October 2004, probed the reasons why we aren't using mosquito repellent.

"We asked why: Is it because it smells? Is it because you are concerned about the health effects of DEET? But less than 15 percent of people say these things," Zielinski-Gutierrez says. "Almost half of people say, "I just forgot about it," or "I didn't see any mosquitoes," or "I just wasn't thinking about it."

In 2003, Colorado had nearly 3,000 cases of West Nile virus. This year, at the CDC's annual West Nile virus conference, Colorado Department of Public Health epidemiologist John Pape offered a "top 10 list" of reasons why people don't wear DEET-containing repellents:

10. I'm not sure why I didn't use repellent.

9. I'm too lazy/I didn't have time.

8. I used other methods to avoid mosquito bites.

7. It smells bad.

6. (tie) I didn't have any repellent.

5. I don't go outside.

4. I'm concerned about health effects of DEET.

3. I forgot.

2. I don't see mosquitoes where I live.

1. I'm not worried/I'm not at risk.

Are these good excuses? Zielinski-Gutierrez doesn't think so.

"One mosquito bite can transmit West Nile virus," she warns. "Putting on repellent takes a few seconds and can avoid the potential lifelong implications of getting infected."

It's especially important for the over-50 crowd to use repellent. West Nile disease is particularly dangerous for those over 50 — yet people over 50 are among those least likely to use repellent.

Read WebMD's "Are You a Mosquito Magnet?"

New Repellents Available

This year, the Environmental Protection Agency (EPA) announced that two new kinds of mosquito repellents work as well as DEET, although for shorter periods of exposure.

One is picaridin. The other is a chemical extract called oil lemon eucalyptus.

"These additional products are for short-term exposure — if you're in the backyard for a couple of hours —- although a stronger version of picaridin should be available in the future," Zielinski-Gutierrez says. "You can use them in the same situation as the family-style DEET products. Neither of these new products are go-canoeing-in-the-swamp kind of products."

Some, however, may prefer the new products. The picaridin product has little odor. The oil-of-lemon eucalyptus product has a strong odor that some may find less obnoxious than DEET. However, it is NOT approved for children under the age of 3 years (and NO repellent is safe for children younger than 2 months of age).

What About Kids?

Some parents worry about using DEET on children. James R. Roberts, MD, MPH, associate professor of pediatrics at the Medical University of South Carolina, recently reviewed the new products for the American Academy of Pediatrics.

"I don't know if the new products are safer for children than DEET — they have been on the market a lot less time," Roberts tells WebMD. "Animal studies showed only minor toxicities."

For his own kids, Roberts still uses DEET.

"I personally use DEET on my children, the 10 percent to 20 percent strengths," he says. "The most important thing is to just apply it once a day. I do tell parents to wash it off the kids at night. I definitely recommend to my patients and students that they wash it off their kids as soon as they come indoors. And don't apply it to kids' hands, because those hands go straight to their mouths and eyes."

There's also evidence that sunscreen may increase the body's absorption of insect repellent.

"I don't recommend using mosquito repellent with sunscreen," Roberts says. "Sunscreen needs to be reapplied after swimming. And you don't want to reapply the repellent."

Read WebMD's "West Nile Virus: First Human Case of 2005"

Recommended Precautions for Repellents

The EPA's full list of precautions to take with mosquito repellents:

— Apply only to exposed skin.

— Never apply under clothing.

— Do not apply to the eyes or mouth.

— Use only sparingly around ears.

— When using spray product, do not spray the face. Spray product on the hands, and apply to face.

— Do not allow children to handle the products.

— Do not spray in enclosed areas or around food.

— Use only enough repellent to cover exposed skin and/or clothing. Saturation is not necessary. If a thin film isn't working, use just a little more.

— Wash repellent off when coming indoors.

— Wash repellent-treated clothing before wearing again.

— If you think you or a child is having a reaction to a repellent, wash the treated skin and call a local poison control center. If you go to a doctor, take the repellent with you.

— Always read the product label before using a repellent.

"I am a new mommy, and it is a whole new world of worry," Zielinski-Gutierrez says. "I do so many things to make sure the baby is fine. I would feel terrible if I didn't take care of myself and got disabled because of a mosquito bite. So I spray the whole family before we go out on walks every evening. I don't want to omit a simple behavior that could prevent risk to my whole family.'

By Daniel J. DeNoon, reviewed by Michael W. Smith, MD

SOURCES: Roberts, J.R. AAP News, June 2005. CDC. Environmental Protection Agency. American Academy of Pediatrics. Emily Zielinski-Gutierrez, DrPH, behavioral scientist, CDC Division of Vector-Borne Diseases, Ft. Collins, Colo. James R. Roberts, MD, MPH, associate professor of pediatrics, Medical University of South Carolina.