Inspired by some gruesome stories in an MPSIMS thread (find it yourself!) that relate how maggots can infest living, albeit ill, creatures… I wonder what specific mechanism stops maggots from thriving on any living creature. I mean, we’re warm, full of protein-y goodness… why don’t flies lay eggs on people and maggots hatch under our skin? Is it our immune system? I thought that was more along the lines of stopping microscopic critters like bacteria. Clearly SOMETHING is at work to protect us, and I for one am grateful… but since we’re basically walking bags of meat, why don’t maggots chow down?
(Note: if there are any pregnant flies reading this, don’t get any ideas).
I don’t know, but I once saw a show on “maggot therapy”, which is where you smack some maggots on your nasty wound and let them chow down; evidently they don’t eat the healthy tissue and it heals very well. A little disconcerting though.
I would expect that it’s simply your skin in many cases.
A brief google of “maggot therapy” (careful! Google Images ‘helpfully’ provides some matches before the actual links!) leads to this page at the University of California, Irvine, which discusses maggot debridement therapy, in which maggots are deliberately introduced into an open wound to devour infected tissue and spur healing.
There are some parasites that do develop under the skin, such as the guinea worm, renowned for being removed by wrapping the protruding end of the worm around a stick and turning the stick a few centimeters each day.
More on maggot therapy: Case report: maggot therapy in an acute burn (warning: gross as hell, with photos). Supposedly maggots eat away necrotic flesh. Google “maggots” and “necrotic” for way more than you want to know.
Erm, the general reason is increased sanitation which literally washes away eggs and maggots. Without it, they certainly do (did) infest necrotic human tissue. Old herbals are full of vermifuge recipes for getting rid of maggots on infected wounds and raw flesh. Ewwey gross.
Maggots only eat dead (necrotic) tissue. They don’t eat living flesh. That’s how maggot debridement works – they eat the dead stuff and leave the live stuff alone.
Short answer is, it does happen. I can provide a cite, a link to a snopes.com article wherein you will find photos of a living patient with a rare form of cancer which was left unchecked to the point where the skull had been “breached” and the patient had an infestation of maggots munching on his brain. It’s, uh, not pretty, and I don’t feel too comfortable linking the page, but you can find it on snopes.
I’ve also heard several accounts of hikers and plane crash survivors whose exposure to jungle conditions resulted in flies laying eggs in their skin.
It depends on the maggot. Certain maggots eat only dead flesh, while other maggots will eat living tissue. Doctors are careful to use only “good” maggots."
One theory for why humans left Africa was that a lot of them were trying to get away from parasites - there are few flesh-chewing insects outside of the tropics.
Whole skin is harder to penetrate, which discourages many critters, but there are a number out there who don’t view a whole skin as much of an obstacle.
Ask any ER nurse working in an urban area on any continent - they’ve seen maggots and such. In North America and Europe, usually in homeless people or folks who simply can’t care for themselves due to physical/mental disability.
I remember my 8th grade biology teacher telling us this, with pictures, but saying “Don’t worry, they have a much more advanced therapy now. They use a glass rod instead of a stick.”
It is thought more than three billion people have harboured some sort of parasite. Maggots are a little more gruesome than some, but the principle is the same.
People don’t just get up and leave an entire continent for reasons like that. Even if they could have known that the temperate regions existed, and they knew that those regions had fewer “flesh-chewing insects”, and of course there was no possible way to know those things.
People didn’t just leave Africa, the populations expanded and people migrated outwards on the population wave, they didn’t treck. The whole process moved at about 10km/year, hardly the pace of people trying to get away from parasites.
I won’t even comment on the fact that once people left the tropical regions of Africa they promptly migrated straight back into the tropical regions in Asia.
I’m guessing their own selves. Their mouths and digestion aren’t designed for fresh food. They need rotting food. Or “pre-digested” or “aged” or “tenderized”, if you will.