How much bacteria do flies carry?
The house fly and the blowfly together harbour more than 600 different bacteria, according to a DNA analysis. Many are linked with human infections, including stomach bugs, blood poisoning and pneumonia. Flies can spread bacteria from place-to-place on their legs, feet and wings, experiments show.
It is a well-known fact that house flies are a source of bacterial contamination and can act as a mechanical carrier and cause bacterial diseases. It can be postulated that house flies play a major role in spreading antibiotic resistant bacteria.
Unlike mosquitoes that transmit pathogens of human health importance in their saliva, house flies transmit pathogens on their feet and body. As well as leaving behind pathogen-filled footprints, the flies leave their poop on our food.
The longer a fly is on your food, the higher the chance of harmful bacteria, viruses and parasites being transferred to it. If a fly lands on your food and you swat it right away, the food will likely be safe to eat.
The house fly is known to carry pathogens that can cause serious and life-threatening diseases in humans and animals. Over 100 pathogens including bacteria, viruses, fungi and parasites (protozoans and metazoans) have been associated with the insect [8, 9].
The disease is most prevalent in poor, rural communities that lack the infrastructure for basic hygiene, clean water, and proper sanitation. Infection is often spread through infected clothes, contaminated hands, and face seeking flies.
Results of experiments with guinea-pig inclusion conjunctivitis as an animal model show that under laboratory conditions flies can readily transmit this chlamydial ocular infection from one animal to another.
Because flies eat garbage, manure, and other bacteria-laden materials, and because they spit up their stomach contents on surfaces for which humans may make frequent contact, these winged devils are capable of transmitting more than 60 different serious illnesses, including: Typhoid fever. Dysentery. Cholera.
They get into your trash, they swarm to sewage and corpses, they spew on everything, they're covered in bacteria and germs from the (literal) crap they like to land on, and then they walk their grubby little feet all over your food.
Because flies can't chew (who knew?), they have to throw up enzymes onto their food, which dissolves the food so they may slurp it up. So in other words, if a fly lands on your burger and wants a bite, he or she will puke on it.
Do all flies lay eggs in human skin?
Many of the flies do not lay eggs on humans. Instead, the flies lay their eggs on other insects (such as mosquitoes) or on objects (such as drying laundry) that may come into contact with people's skin. Eggs hatch into larvae, which burrow into the skin and develop into mature larvae.
References
- https://www.sydney.edu.au/news-opinion/news/2016/01/04/should-i-throw-away-food-once-a-fly-has-landed-on-it-.html
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449784/
- https://nowthisnews.com/videos/food/you-might-want-to-throw-away-your-food-if-a-fly-lands-on-it
- https://www.verywellhealth.com/are-flies-dirty-1124119
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6104014/
- https://pubmed.ncbi.nlm.nih.gov/7459318/
- https://www.womansday.com/food-recipes/food-drinks/news/a50683/the-disgusting-reason-you-should-never-eat-something-a-fly-landed-on/
- https://www.sciencealert.com/houseflies-blowflies-carry-more-diseases-than-thought-bacteria-pathogens
- https://www.merckmanuals.com/home/skin-disorders/parasitic-skin-infections/cutaneous-myiasis
- https://www.bbc.com/news/science-environment-42113217
- https://www.liebertpub.com/doi/10.1089/vbz.2021.0021