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Mosquito Tests Positive for West Nile Virus in Tredyffrin

It's the first mosquito that's tested positive for West Nile Virus in Chester County in 2016.

TREDYFFRIN, PA – A mosquito has tested positive for West Nile Virus in Tredyffrin Township, the Chester County Health Department announced Tuesday morning.

The mosquito was collected on July 7, officials said.

It's the first mosquito that's tested positive for West Nile Virus in Chester County in 2016.

Find out what's happening in Tredyffrin-Easttownwith free, real-time updates from Patch.

Mosquitoes are trapped around the county in breeding areas and tested for West Nile as part of routine surveillance.

The county said they are continuing to monitor these areas and "will consider control activities when appropriate." Chemical spraying was done by the county in several area municipalities in 2015, including Phoenixville and East Whiteland.

Find out what's happening in Tredyffrin-Easttownwith free, real-time updates from Patch.

The risk of being infected with West Nile from a mosquito is very low, officials said, but residents are still urged to take simple precautions, like using repellent and removing standing water from their property.

The Health Department has also issued the following guidelines to help residents:

  • Limit outdoor activities at dawn and dusk during warmer months since most types of mosquitoes bite most frequently during these times. Be aware though that some types of mosquitoes bite most frequently during the daytime.
  • Wear long-sleeved shirts and long pants, and socks. Choose clothing that is light colored and made of tightly woven material.
  • Stay in places with air conditioning and window and door screens to keep mosquitoes outside.
  • Sleep under a mosquito bed net if you are overseas or outside.
  • If you choose to use insect repellents, use Environmental Protection Agency (EPA)-registered repellents with one of the following active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol. Choosing an EPA-registered repellent ensures the EPA has evaluated the product for effectiveness. When used as directed, EPA-registered repellents are proven safe and effective, even for pregnant and breast-feeding women.
    • Always read and follow the product label instructions carefully.
    • Reapply insect repellent as directed.
    • Do NOT spray repellent on the skin under clothing.
    • If you are also using sunscreen, apply sunscreen before applying insect repellent.
  • To protect your child from mosquito bites:
    • Do NOT use insect repellent on babies younger than 2 months old.
    • Do NOT use products containing oil of lemon eucalyptus or para-menthane-diol on children younger than 3 years old.
    • Do NOT apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
    • Adults: Spray insect repellent onto your hands and then apply to a child’s face.
    • Dress your child in clothing that covers arms and legs.
    • Cover cribs, strollers, and baby carriers with mosquito netting.
  • Clothing and gear treated with permethrin or permethrin spray for clothing is available for purchase. Read and follow product information carefully to determine if this is a solution for you.
    • Treated clothing remains protective after multiple washings. See product information to learn how long the protection will last.
    • If treating items yourself, follow the product instructions carefully.
    • Do NOT use permethrin products directly on skin. They are intended to treat clothing.
  • To protect your pets:
    • Do NOT use any product on pets unless it is specifically made for pets.

The Health Department also encourages the public to:

  • Cover or empty containers such as trash cans, wading pools, wheelbarrows, and pots.
  • Turn containers upside down when not in use so they don’t collect water.
  • Drill holes in the bottom of recycling containers.
  • Get rid of old tires.
  • Change the water in bird baths every three to five days.
  • Check storm drains, window wells, and underneath leaky faucets for standing water.
  • Clean roof gutters every year.
  • Aerate and/or stock ornamental ponds with fish.
  • Keep swimming pools clean and chlorinated. Make sure that water does not gather on swimming pool covers.
  • Treat a pool of standing water that cannot be drained with Bti products. Bti is a naturally-occurring bacterial product that kills mosquito larvae and is safe for people, pets, aquatic life, and plants. You can find these products at local lawn and garden supply stores.
  • Make sure that window and door screens fit tightly to keep mosquitoes out of your home.
  • Run electric fans nearby when spending time outdoors. Mosquitoes have trouble flying in strong winds.
  • Replace outdoor lights with yellow "bug" lights, which tend to attract fewer mosquitoes than ordinary lights.


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