Deer flies are one of the few types of flies that transmit disease to people in the United States. ... Both deer flies and horse flies bite with scissor-like mouthparts that cut into skin, causing blood flow which the flies lap up. Because of this relatively crude means of obtaining blood, the bites can be painful.

What happens when a deer fly bites you?

Deer fly bites are painful, and will cause red bumps or welts. They transmit a rare bacterial disease known as rabbit fever (tularemia). Symptoms include skin ulcers, fever, and headache. Tularemia can be successfully treated with antibiotics, but without treatment, it can be fatal.

Does a deer fly bite hurt?

Deer fly bites can be very painful, and some people also experience an allergic reaction to the salivary secretions released by the insects as they feed.