UNIVERSITY PARK, Pa. -- As the warm months of Summer set in, so does the unmistakable "itch" - biting insects have returned for another season! Some of these biting insects, like mosquitoes, can carry diseases like West Nile encephalitis. What is West Nile encephalitis and what can you do to protect yourself?
In 1999, 62 people in the New York City metropolitan area were hospitalized with West Nile encephalitis, an infection that causes inflammation of the brain caused by West Nile virus previously limited to Africa, Eastern Europe, Middle East, and West Asia. According to the Centers for Disease Control and Prevention, all residents of areas where virus activity has been identified are at risk of getting West Nile encephalitis; people over 50 have the highest risk of severe disease.
West Nile encephalitis cases occur primarily in the late summer or early Fall. Mosquitoes get West Nile virus when they bite, or take a blood meal, from infected birds. Mosquitoes then transmit the virus to people and other animals when biting them. Symptoms of West Nile encephalitis include fever, headache, body aches, mild skin rash, or swollen lymph glands.
The Pennsylvania Departments of Health and Environmental Protection and other state and local agencies monitor Pennsylvania for potential mosquito and bird carriers of the virus. Last year, Pennsylvania had nine human West Nile virus cases. To see if West Nile virus has been detected in your County, visit Web site http://www.westnile.state.pa.us/surv.htm.
What can you do to lessen your chances of contracting West Nile encephalitis and safely keeping mosquitoes at bay? According to Lyn Garling of the Pennsylvania IPM Program, it helps to learn a little about the mosquitoes that carry the virus. "There are two species of mosquitoes that have the potential to carry the disease, but Culex pipiens is the most common and primary carrier of the virus in Pennsylvania," says Garling. "It has a very small home range and usually does not fly more than 300 feet from a breeding site. Because this mosquito lays its eggs in small pools of standing water containing leaves or other debris, backyards can be the perfect habitat. Once they find a breeding site, they tend to stay in the area. Consequently, the first line of defense is to prevent mosquitoes by eliminating unwanted standing water around the home."
Tips from the Pennsylvania Department of Environmental Protection:
* Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers that have collected on your property.
* Get rid of discarded tires. Stagnant water in tires is where most mosquitoes breed.
* Drill holes in the bottom of recycling containers left outdoors.
* Clean clogged roof gutters every year, particularly if the leaves from surrounding trees have a tendency to plug up the drains.
* Turn over plastic wading pools when not in use.
* Turn over wheelbarrows and don't let water stagnate in birdbaths.
* Aerate ornamental pools or stock them with mosquito-eating fish such as goldfish. Water gardens can become major mosquito producers if they are allowed to stagnate.
* Clean and chlorinate swimming pools not in use. Be aware that mosquitoes can breed in the water.
For stagnant pools of water that cannot be eliminated or flushed out regularly, you can try less-toxic means of control that won't pollute water resources like some traditional pesticides. Residents can buy the microbial pesticide Bacillus thuringiensis israelensis (Bti) at lawn and garden centers or home improvement stores. These products, sold under the trade names "Mosquito Dunk" and "Quick Kill Mosquito Bites", contain a naturally occurring bacterium that targets and kills mosquito larvae but is safe for people, pets, aquatic life and plants. Remember to only use chemicals registered for mosquito larvae in water. Do not use bleach or other household chemicals.
Take precautions to prevent being bit by mosquitoes:
* Consider wearing long-sleeved shirts, long pants and socks outdoors, particularly when mosquitoes are most active at dawn and dusk or in areas known for having large numbers of mosquitoes.
* Reduce outdoor exposure at dawn and dusk during peak mosquito periods, usually April through October.
* Keep windows and doors tightly screened.
For the mosquitoes that still manage to pester you, consider using insect repellents according to the manufacturers' instructions. An effective repellent may contain different active ingredients so read the product label before purchasing. Increasingly, there are warnings about the uses of repellents containing DEET on children so it may be a good idea to use some of the effective alternatives recommended by the American Academy of Pediatrics. Products with picaridin, soy oil and oil of lemon eucalyptus have been shown to be as effective as the lower concentrations of DEET (~7-15% range).
If you do use DEET, make sure to:
* Apply sparingly to exposed skin and clothing using a product that contains no more that 10 to 35 percent DEET.
* Women who are pregnant should not use DEET, and it shouldn't be applied to children under the age of three. A product that contains no more than 10 percent DEET may be applied on older children. Avoid spraying the product directly onto children's skin, and avoid applying to hands and face.
* Once indoors, wash all treated skin and clothing with soap and water separately from other laundry.
Garling does not recommend the use of pesticide-impregnated clothing, recently available at some outdoor clothing stores. "Sold under brand names such as "Buzz Off!" these clothes contains the pesticide active ingredient permethrin, a synthetic version of naturally occurring pyrethrins. In humans, permethrin may trigger asthma attacks, headaches, nausea and other health problems and is a possible human carcinogen," Garling explains. "Although the EPA has required testing of these products and has explained that they poses minimal risk to individuals (see http://paipm.cas.psu.edu/pdf/PesticideImprgnClothing07.pdf), questions remain in my mind", Garling says. "Do people know they are buying a pesticide to wear against their skin when they buy this product? Do they know the label recommendations on the garment requiring that they wash this clothing separate from their other clothes is the law? Will they read and follow these recommendations? Also, the jury is still out on whether or not permethrin is an endocrine disruptor, so, would you put this clothing on kids? We have good insect repellents on the market so I don't see the need to take additional risks, however small, with wash and wear pesticidal clothing." Other individuals and groups have similar questions. (See Web sites http://www.thegreenguide.come/doc/ask/buzzoff, and http://www.beyondpesticides.org/news/daaily_news_archive/2006/09_14_06.htm)
For more information on mosquito control and how to protect yourself from West Nile encephalitis, visit PA IPM's Pest Problem Solver at http://paipm.cas.psu.edu/ProblemSolvers/PHealthProblSolv.htm#mosq. For more information on West Nile encephalitis, visit Pennsylvania's West Nile Virus Surveillance program at Web site http://www.westnile.state.pa.us/. You may also visit Penn State's College of Agricultural Science's Web site on West Nile virus at http://www.pested.psu.edu/issues/wnv/.
The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and urban settings. For more information, contact the program at (814) 865-2839, or Web site http://www.paipm.org. To view our archived news releases, see Web site http://paipm.cas.psu.edu/newsrelease.html.
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Editors Contact: Kristie Auman-Bauer PA IPM Program (814) 865-2839 kma147@psu.edu