Airborne insects in the Diptera order include common pests like mosquitoes, houseflies and fruit flies, just to name a few. Many insect pests of this order bite humans, which can spread a variety of disease-causing microorganisms, or cause tissue trauma that can lead to secondary infections. For example, mosquitoes are biological vectors for a number of human and animal diseases, including the Zika virus, West Nile virus, yellow fever, and eastern equine encephalitis (EEE). This year has seen an unprecedented amount of Massachusetts residents fall victim to EEE from bites inflicted by infected mosquitoes, but several other Diptera fly pests are particularly problematic in the northeast. These fly pests include greenhead flies, black flies, horse flies, stable flies and deer flies. While nearly all Diptera fly pests suck blood from humans, their mouthparts differ depending on the species.
Some airborne insect pests, like dragonflies, possess four wings, but flies in the Diptera order possess only two wings, as well as mouthparts that are designed for piercing and/or lapping up liquids, mainly blood. Mosquitoes and biting flies pinpoint the location of human and animal blood-hosts by sensing the carbon dioxide and moisture in exhaled breath. Some Diptera fly pests, like greenhead flies, are attracted to people wearing dark colors, and nearly all Diptera fly pests gravitate toward movement, warmth and perspiration. Diptera fly pests pose a public health threat, and if a person sustains a bite from one of these pests, the species of pest should be identified to assess the bite victim’s risk of contracting disease. For example, one deer fly species in the northeast, Chrysops discalis, can transmit tularemia to humans with its bite, and common biting midges can transmit a number of human diseases. Also, bites from black flies, deer flies and horse flies can trigger severe allergic reactions in some individuals. The most reliable insect repellents currently on the market contain either DEET or picaridin, but not all biting fly species respond in the same way to these repellents. This is why repellents should be used in combination with other measures to protect against fly bites, such as wearing long sleeves and a hat or by avoiding outdoor areas where biting flies are known to be problematic.
Have you ever sustained a bite from a fly that drew blood?