Black flies, often called “buffalo gnats,” are small, dark insects that can be a nuisance to humans and animals. Female black flies bite to obtain a blood meal.
Characteristics of a Black Fly Bite
Black flies use specialized mouthparts to cut into the skin, allowing them to feed on blood. The bite feels sharp or painful. A small puncture wound is visible, often surrounded by redness and swelling. The affected area becomes itchy, and a raised welt similar to a mosquito bite develops.
Understanding the Health Effects
Reactions to black fly bites can vary significantly among individuals. Common responses include localized swelling, itching, and discomfort at the bite site. Some individuals may experience more widespread symptoms, a condition sometimes referred to as “black fly fever”. This systemic reaction can include headache, nausea, low-grade fever, and swollen lymph nodes.
Black flies are not known to transmit diseases to humans in the United States. However, in certain regions of the world, such as equatorial Africa and parts of Central and South America, black flies can transmit the parasitic nematode worm Onchocerca volvulus, which causes onchocerciasis, also known as “river blindness”.
Strategies for Bite Prevention
Avoiding black fly bites involves several practical measures. Wearing protective clothing, such as long-sleeved shirts and long pants, can help shield the skin from bites. Light-colored clothing is often recommended, as dark colors may attract these insects. Tucking pant legs into socks and using zippered garments can further prevent flies from accessing the skin.
Insect repellents containing active ingredients like DEET or picaridin are also effective against black flies. Black flies are most active during the day, particularly from mid-morning to late afternoon, and especially on humid, cloudy days. Avoiding outdoor activities during these peak times and staying away from their breeding grounds near flowing water can also reduce exposure.
Care for Black Fly Bites
Once a black fly bite has occurred, several steps can help alleviate symptoms and promote healing. Cleaning the bite area with mild soap and water can help reduce irritation and lower the risk of infection. Applying a cold compress or ice pack to the bite for about 10-15 minutes can help reduce swelling and discomfort. Over-the-counter anti-itch creams, such as hydrocortisone or calamine lotion, can be applied to the affected area to relieve itching. Oral antihistamines can also be taken to manage widespread itching and irritation.
Avoid scratching the bites, as this can break the skin and increase the chance of secondary bacterial infections. Seek medical attention if signs of infection develop, such as increased redness, warmth, pus, or persistent pain, or if severe allergic reactions like difficulty breathing or significant swelling occur.