ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Tuesday, June 18, 1996 TAG: 9606180034
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: ALESSANDRA SOLER STAFF WRITER
Here's the latest buzz on mosquitoes: Grab some repellant, because hordes of 'em are sure to follow Western Virginia's monsoon season
WITH 3,000 kinds of them worldwide they're simply unavoidable. Chances are, you'll find some of them frolicking about in the plastic kiddy pool you left in the back yard overnight.
We're talking about mosquitoes here, and, largely because of the recent rainfall - and because it's nearly summer, after all - you'll soon run across a whole bunch of them. In fact, there are about 50 species lucky enough to call Virginia home, so it's highly unlikely you'll get by these next few months without suffering the throbbing pain of a nasty bug bite.
"We had a nice, wet spring, which brought a real good crop of spring mosquitoes," said Joe Kertesz, mid-Atlantic regional director for the American Mosquito Control Association. "And if the weather pattern stays like this then we'll definitely see a lot more insects in the summer."
Fortunately, not all of them are blood suckers, searching for hearty, protein-rich meals. Ralph Williams, an entomologist at Purdue University in Indiana, says that only about a dozen species are aggressively annoying.
"What we're mostly seeing right now in this region are more nuisance-biting not disease-carrying mosquitoes," he said.
William Faulkner named his second - and, incidentally, worst-selling - novel, "Mosquitoes," after the bugs that infest the area near Lake Pontchartrain in New Orleans. But folks who live near swampy marsh lands aren't the only ones who will suffer from the itching and swelling of mosquito bites this summer. Williams, who makes his living studying the pestering habits of these insects, said the eastern half of the country will come across most of the problems within the next couple of months.
"Every state has its own pattern of problems," said Sally Paulson, associate professor of entomology at Virginia Tech. "For instance, up in the Arctic there is a brief period of time in the spring where mosquitoes are just unbearable. And here in Virginia we have a problem with mosquitoes much like in Florida mainly because of our significant coastline. Salt marsh mosquitoes are a problem for us as well, just not all year around."
Here are some facts you may not already know about mosquitoes - and some tips on how to keep them at arm's length:
* It's the females that are vicious. Although they also feed on plant juices and nectar, female mosquitoes have a particular liking for fresh blood. They need the protein for egg development, and any innocent bystander willing to share some exposed skin will do the job nicely.
"They secrete saliva in the process of injecting their mouth parts into our skin and that allows them to get a blood meal," Williams said. "Our own body reacts to this invasion by releasing a histamine, and that's what causes the itching and swelling."
* Wet, not hot, weather helps entomologists predict the amount of mosquito infestation. And the insects don't just die in the winter. Instead, they wait patiently - under a leaf perhaps - for spring when standing water, the breeding ground for mosquitoes, tends to collect.
"Most of the eggs can survive between five to seven winters simply waiting for a flood to hatch," Kertesz said.
* That one mosquito that seems to follow you around absolutely everywhere you go is probably an Asian tiger mosquito, one of the most aggressive biters in southwest Virginia. But once it has gotten its fix for the day it'll leave you alone. "It won't torment you for the rest of the night," Paulson said. "Once it bites you it doesn't need you anymore." The eastern treehole and the floodpool mosquitoes also are readily found in the Roanoke Valley.
* Draining standing water is one solution for getting rid of mosquitoes - at least temporarily. "The Asian tiger mosquito tends to breed in artificial containers like garbage cans, old tires, kiddy pools and bird baths, and people can do a lot to reduce their problems just by getting rid of these breeding sites," explained Paulson.
* Avon's Skin So Soft smells good and feels nice and smooth, but experts say it won't last as long as insect repellents (though many people still swear by the product). The most effective ones contain Deet, the common name for the chemical, N, N-Diethyl-meta-toluamide. The Department of Public Health suggests using repellents containing 15 percent of Deet or less, especially on kids. According to Richard Fell, professor of entomology at Virginia Tech, repellents containing 10 percent to 20 percent of Deet will work just as well as those containing 90 percent or more, but for a shorter time. Most repellents applied to skin and clothing will only prevent bites for one to five hours, depending on the person, type and number of mosquitoes, and the type and percent of active ingredients in the repellent.
* The "mosquito repellent plant" that produces citronella oil works just about as well as wrinkle cream does. Citronella oil repels mosquitoes only at high concentrations, and the amount released by the plant just isn't enough - and that goes for candles too, entomologists say.
* Ultraviolet or black lights and sonic devices look and sound cool, but when it comes to getting bugs out of your yard, they're useless.
"Some bugs are actually attracted to ultraviolet lights so that'll just increase the problem," Fell said. "And most of the mosquitoes can't even hear the sonic devices."
* If you're building a bird house for anything other than bird watching, you're wasting your time. According to Kertesz, who also works for the Hampton mosquito control commission, mosquitoes make up about 2 percent of the diet of the purple martin, a bird generally thought to help reduce mosquito infestation. Although the birds can eat several hundred mosquitoes in one evening, they're outnumbered by these quick-moving nuisances.
"These are pretty big birds and they eat these insects for energy," explained Kertesz. "The mosquitoes are too small to provide enough of this energy, so [the birds] generally stick to flies and other larger insects."
* Experts say that bats, however, are quite effective at reducing the mosquito population. "Bats are probably more important than birds," Paulson said. "A lot of people have put up bat houses, and it does help lessen the problem."
* You cannot get AIDS from a mosquito on a blood meal rampage. Studies conducted by researchers at the Center for Disease Control have shown no evidence of HIV transmission through insects, doctors say. When a mosquito bites a person, it doesn't inject its own blood - or the blood of a previous victim - into its new prey.
* Encephalitis, a viral inflammation of the brain that can affect humans as well as horses, is Virginia's most serious mosquito-related problem, Paulson said. "It's an under-reported kind of disease. Normally it cycles in wild birds and they don't have a problem with it. It's when it gets into horses and humans, then it can be deadly." There are no vaccines against the various types of encephalitis, Fell said. The best way to avoid the illness is to clean up breeding sites and limit exposure to outdoors during the mosquitoes' mealtimes (early dawn and dusk).
* Mosquito-borne yellow fever and malaria have caused large epidemics among humans - though the U.S. has been relatively free of this problem for decades. "These are the kinds of diseases that have co-evolved with the mosquito for hundreds of thousands of years," Fell said. During the sporozoite stage of development, in the case of malaria for example, the disease migrates into the salivary glands (rather than blood) of the mosquito. This, Fell said, is when infection occurs. "You're getting these particles that are being translocated and then reinjected into the host when the animal feeds. If the disease goes straight to the animal's gut, there won't be a problem. But in most cases, it doesn't happen that way."
* Both dogs and cats can get filariae - or heartworms -from mosquitoes. "You can go to the vet and have your animals checked out and all, but ultimately it's up to the pet owners themselves," Paulson said. "A dog that's tied up in the back yard all day is going to have more bites than one that's just taken out for daily walks."
LENGTH: Long : 140 lines ILLUSTRATION: PHOTO: LEONARD MUNSTERMANN. The treehole mosquito, Aedesby CNBtriseriatus, is common in urban settings in the Eastern United
States. Among its breeding grounds are tin cans, old tires and, of
course, holes in trees. color.