Blow Flies Health Concerns

Do Blow Flies Bite?

Although they make loud buzzing sounds, blow flies do not bite humans. However, blow flies do pose dangerous health threats to humans and animals. Maggots can infest living animals, resulting in a parasitic condition known as myiasis. Interestingly, maggot debridement therapy (MDT) is used to treat some diseases, by allowing maggots to clean non-healing wounds, but that should only be done under medical supervision.

How Blow Flies Affect People and Pets

For people, the main risk is contamination rather than injury. Adult blow flies feed and lay eggs on carcasses, garbage and animal waste, then may land on food, counters and dishes, carrying bacteria on their feet, mouthparts and bodies. A fly touching down on your plate once is not a cause for alarm, but food that flies have been crawling over for a while, especially meat, is better thrown out.

Pets and livestock face more risk than people. Some blow flies lay eggs in open wounds or in fur soiled with urine or feces, and the maggots then feed on the animal’s tissue. In Florida’s heat this can develop quickly, particularly in older, overweight or long-haired pets and animals that can’t groom themselves well. Check outdoor pets daily, and keep wounds clean and covered.

A related fly, the New World screwworm, attacks living animals. It was found in Key deer in the Lower Keys in 2016 and was eradicated there through releases of sterile flies. Any suspected case should go to a veterinarian right away.

When to get help:

• See a vet the same day if you find maggots in a wound, notice a foul smell from a pet’s coat, or your pet is lethargic and hiding.
• People rarely get maggot infestations, but anyone with maggots in a wound should see a doctor rather than try to remove them at home.

To cut down on flies around the house, see how to get rid of blow flies.