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Biting Flies

Deer and horse flies are well known for buzzing relentlessly around their target, landing stealthily on exposed skin, and delivering a painful bite. Their bite can itch for days and scratching may lead to infection. These flies are active during the day and are especially common around ponds, streams, marshes, and lakes. They are capable of transmitting tularemia to people, a bacterial disease that flies can pick up from wild animals. The bites can also cause severe allergic reactions for some people.

Prevent Fly Bites

  • Avoid places where flies are most active, particularly from dusk to dawn.
  • Cover exposed skin by wearing light-colored, long sleeved shirts, pants and hats.
  • Consider using a repellent labeled for biting fly protection. Always follow label instructions carefully.
  • Fix window and door screens.
  • Clean up piles of rubbish and decaying hay, straw, and other vegetation that attract flies.


When a fly bites, it injects saliva into the skin. This saliva can cause swelling, itchiness, and mild redness at the bite site. For some people, the fly's saliva can trigger life-threatening allergic reactions.

  • Wash the bite site thoroughly with soap and water.
  • Take an antihistamine or apply creams to reduce itching if necessary.
  • Watch for symptoms of infection over the next several days. Symptoms include increasing redness, swelling, or pain.

Allergic Reactions

Call 911 if any of these signs occur:

  • Trouble breathing, wheezing, or shortness of breath.
  • Swelling anywhere on the face or in the mouth.
  • Throat tightness or difficulty swallowing.
  • Feeling faint or dizzy.
  • Turning blue.

More Resources


Content Source: Zoonotic Disease Program