According to Real Simple, fly bites, including deer and horsefly bites, can be treated by washing the bite with soap and water and applying an ice compress to the bite for 15 minutes several times a day. Deer and horsefly bites can cause bleeding, and medical attention is recommended if the bleeding does not stop on its own.
Deer flies are about one-quarter to one-half inch in length, notes Healthline. They are usually brownish-black and have transparent wings. The head of the deer fly is round and small, and its eyes can be either green or gold. Most deer flies make their homes around swamps, lakes or other bodies of water. Although deer flies are commonly seen on hot summer days, they are usually more active during spring. Regardless of the season, deer flies are traditionally more active during the day and become less active during the night. Deer flies feed on the blood of humans and animals.
Deer flies are one of the few species of flies in the United States that can transmit disease to people, such as tularemia, according to the Illinois Department of Public Health. More commonly referred to as rabbit fever, it is a type of bacterial disease that can be acquired after coming into contact with an animal or object that already has the disease.