The next time a fly lands on your food, you might want to consider throwing away that bite. A new review suggests that the muck that flies regurgitate can be very well contaminated with pathogens.
When you think of a disease-carrying insect, you might think of a blood-sucking mosquito or tick. But recent findings suggest that your average non-biting house will fly (House fly) may pose a greater threat to human health than is often thought.
Houseflies contain an organ known as the crop at the beginning of their gut, which stores food before digestion. This makes the body a good place for microbes and parasites to hide.
When a fly lands on your foodIt is more likely that the insects will regurgitate some of the contents and some of the digestive enzymes that they have digested. If there are no teeth, this is how the fly breaks down its food, and swallows it with its straw-like mouth.
In addition to spitting out enzymes, the fly can resurface. Viruses and bacteria from the crop, previously picked up from other food sources such as wounds, saliva, mucus or ashes.
A recent review of this neglected transmission line was initially prompted by an outbreak of disease. Covid-19 EpidemicWhen the author read the book, entomologist John Stofolano Spillover: Animal Infections and the Next Human Pandemic.
As Stofolano flipped through the pages, he realized that the houseflies he had been working on for more than half a century had been neglected as disease vectors.
“I was working [non-biting] It has flown since I was a graduate student in the 1960s. And [non-biting] Flies are largely ignored.” He says. Stofolano from the University of Massachusetts Amherst.
“Blood-sucking flies have taken a big place, but we have to watch out for those living among us because they get their food from humans and animals because they shed pathogens through their tears, feces and wounds.”
Because flies are attracted to waste, such as dead animals and feces, non-biting insects can transmit pathogens as they move from one animal to another.
As one says A recent studyMore than 200 different pathogens have been found in adult houseflies, including some bacteria, viruses, worms, and fungi.
But it’s not just mechanical transmission that we have to worry about. In the 1990s Research found that Escherichia coli Bacteria can spread in and out of the mouth of houseflies.
At first glance, Stofolano thinks this is because the flies constantly spit out the contents of their crop during feeding and feeding (insects spit).
In 2021, for example, a Research They discovered that houseflies were infected. Chlamydia tachomatis This pathogen can survive in crops for up to 24 hours – plenty of time to fly and reintroduce it to a new host.
other Research Pathogens can remain in the crop for at least 4 days.
While scientists continue to work to understand these nasty creatures, keep in mind that the risk is minimal if food isn’t left out for long periods of time.
“While there is little doubt that flies can carry bacteria, viruses and parasites from waste to our food, a single contact is unlikely to trigger a chain reaction that leads to illness in the average healthy person,” said University of Sydney entomologist Cameron Webb. He wrote In 2015
However, to date, many studies that have investigated the internal organs of flies have not identified the internal organs of the fly. Stefano said researchers should investigate microbes and possibly parasites because there is so much liquid to wash the crop.
Researchers note that some species of flies have larger crops and may carry more pathogens, and those insects may pose a greater threat as they roam.
“It’s the little things that make the problem,” Stofolano He says.. “Our health depends on paying attention to these flies that live with us.”
The study was published in Insects.