Insects Making Pests of Themselves

For travelers headed into Southern California’s great outdoors this summer, there’s good news and there’s bad where pests are concerned.

The mosquito population is dwindling. The risk of Lyme disease--a much dreaded tick-borne inflammatory disorder--remains low. It will probably be a boom year for spiders, though.

But vacationers who arm themselves with effective insect repellent and with information can increase their chances of enjoying a bite-free, sting-free camping or hiking trip.

Mosquitoes, for example, are more active in the summer when temperatures are higher and during early evening hours, said Roy Martin, an associate resource ecologist for the California Department of Parks & Recreation. They also tend to be more prevalent around stagnant pools of water. In areas where abatement programs are in place--including most of Los Angeles County--mosquitoes are less of a problem, said Gail Van Gordon, a public health entomologist with the Los Angeles County Department of Health Services.

Publicity about Lyme disease has made many travelers unusually anxious, the experts said. But in Southern California the risk is “extremely low,” according to Van Gordon. The tick most likely to affect Southern California hikers and campers, she said, is the American dog tick, which does not transmit Lyme disease. (It does, however, transmit other diseases such as Rocky Mountain spotted fever and tick paralysis.)

The risk of Lyme disease, transmitted by the deer tick and the Western black-legged tick, is much greater in areas other than Southern California, according to the federal Centers for Disease Control and Prevention.

Higher-risk areas include Northern California, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania, Maryland, Delaware, Wisconsin, Minnesota and Michigan. Lyme disease is rare in the Rocky Mountain states, as well as in Hawaii and Alaska, according to the CDC.

Later-than-normal rainfall--prompting unusually moist conditions--will probably cause the Southern California spider population to swell, Van Gordon said. But most spiders encountered in this area are fairly harmless, she said, with two exceptions: the female black widow and the South American violin.

A female black widow is relatively large with a shiny, black, swollen abdomen and a red hourglass marking on the underside of its abdomen, Van Gordon said. The South American violin spider, which is brown with violin-shaped markings, is more likely found in dark basements than outdoors, Van Gordon said.

In addition to knowing which pests are prevalent and where they are likely to be found, dressing properly can help. Wear long pants and long sleeves. Avoid wearing cologne, floral-patterned clothing, scented hair spray or scented lotions, experts advise, because all can attract insects.

Insect repellents can help. Those with DEET (N, N diethyl-m-toluamide) are one option. “DEET is effective but should not be used in concentrations above 25% or 30%,” Moore said.

For young children and teen-agers, use no more than 10% DEET, Theriot said. “Spread it evenly. Don’t put it on the hands and fingers of young kids,” he added. Check with a pediatrician before using DEET or other repellents on children 2 or younger, said an American Academy of Pediatrics spokeswoman.

Alternatives to DEET-based repellents are formulas with citronella, the same ingredient as is found in patio candles designed to repel insects. Another over-the-counter repellent, Natrapel, for example, contains aloe vera and citronella but not DEET.

Rinse off all insect repellents when children come indoors, Theriot advised.

Despite preventive measures, insect bites will undoubtedly still occur and most will prove harmless. If the bite is from a tick, remove the tick as soon as possible.

Early symptoms of Lyme disease include a bite-site rash in the shape of a bull’s eye or target pattern, experts said. Flu-like symptoms can occur, including headache, fever and fatigue.

Travelers worried about Lyme disease should ask their physician about getting a blood test if there is reason to suspect they have been bitten by a tick from a location where the disease is prevalent. Oral antibiotics are the usual treatment. If there are other unusual symptoms after a tick bite, seeking professional help is advised.

Many spider bites go unnoticed. But bites from a black widow produce immediate pain that can travel through the body and affect muscles, Van Gordon said. The bite site of a South American violin “looks like acid has been dropped on the skin,” she said. Get immediate medical help if bites from these spiders are suspected, Theriot said.