Not all mosquito repellents are created equal

Mosquito bites can be more than an annoyance. For the unlucky, getting bitten can lead to West Nile virus, a potentially serious illness that the U.S. Centers for Disease Control and Prevention says is very likely underdiagnosed and underreported. With West Nile season getting underway, and mosquitoes and birds recently testing positive for the virus from Philadelphia's suburbs to California, the agency is spreading the word on prevention.

One of the latest developments for consumers is a recently recommended source of protection that guards against mosquito bites: In May, the CDC added IR3535, a chemical used in Europe for 20 years and sold in certain Avon products in the United States, to the list of three other safe and effective mosquito repellents. The others are DEET, picaridin, and oil of lemon eucalyptus.

The CDC suggests sticking with the four recommended types of insect repellents rather than taking a risk on other products that may not work as well. "There's lots of other things out there on the market that generally don't work," says Lyle Petersen, director of the CDC's Division of Vector-Borne Infectious Diseases. "These four are proven."

DEET has been used for more than 40 years; picaridin and oil of lemon eucalyptus were added to the CDC's recommendation list a few years ago. The repellents should be applied routinely before going outside, since West Nile is most commonly transmitted through the bite of an infected mosquito, especially between mid-July and mid-September, Petersen suggests.

"Every single year since 2002, we've had major epidemics" of West Nile virus, says Petersen, who himself had a previous bout with West Nile. The illness is "basically here to stay, and it's something that we need to take precautions for every summer."

Five tips for avoiding mosquito bites

The CDC offers the following advice for how to avoid getting bitten by the insects:

• The best way to avoid mosquito bites is to put insect repellents on exposed skin. The CDC recommends four ingredients: DEET, picaridin, oil of lemon eucalyptus (or PMD), and IR3535 (its latest addition to the list, sold by Avon). In addition, permethrin - which can be used on clothing, shoes, camping gear, and bed nets, but not skin - is an option. Directions on insect repellants should indicate how often they should be reapplied and for which age groups they're appropriate.

•Consider wearing long pants and long sleeves when weather allows it, or simply stay indoors at or near dawn and dusk, when West Nile infections tend to occur. "Try and avoid mosquito bites at these times," says the CDC's Lyle Petersen

•Eliminate mosquito breeding sites around your home. These include small pools of water such as a birdbath that's not cleaned out, water at the bottom of a flowerpot, and old buckets or tires with standing water. "Any kind of container can breed mosquitoes," Petersen says. Emptying such containers once or twice a week should do the trick.

•Put screens on your windows and doors - and repair the screens if they have holes in them. Also, use air conditioning so you can keep the windows closed.

•Use mosquito netting on infant carriers when taking your baby outdoors.