(Warning: gross-out material ahead)
With all due respect, Ursa and Irish, either we are talking about different kinds of maggots or you have been mislead.
I don’t have any special maggot-knowledge, but I have worked at a vet clinic for years. I live in the southeast U.S. where maggot infestations are a major concern - employees in one of the local emergency clinics actually run a pool every spring on when the first maggot cat or dog will show up.
While apparently maggots can’t or won’t penetrate normal healthy, unbroken skin, any small abrasion that breaks the outer surface is prone to maggot infestation. Usually an animal will get a slight injury of some kind that it cannot clean properly, either due to location or hair length (we see most infestations in long haired pets). Flies then lay their eggs in or near this broken skin, and when the eggs hatch the maggots begin burrowing into the wound. (Hence the term ‘fly-blown’.)
The most frequent cases of maggont-infestation we see are associated with feces contamination. Usually, an animal is either sick or injured and cannot clean itself, has had severe diarrhea, or has simply had feces matted into some long hair in the perianal region. This feces causes ‘scalding’ - the skin beneath it becomes red and irritated. Flies are attracted to the feces and lay their eggs, and the newly hatched maggots begin feeding on the inflamed, raw skin.
Here comes the gross part! I have seen animals with the skin eaten off of their entire hindquarters. This is usually pretty easy to heal - once the maggots are removed the exposed damaged skin will die and can be debrided, and in most cases will regrow, although there may be significant scarring.
However, in many cases the maggots penetrate the outer skin layers and enter the muscle tissue. Once that happens, the real trouble starts - we had a couple of long haired cats that we eventually had to euthanize because they were pretty much destroyed. One was infested in the shoulder area, and the muscle, etc. was eaten away all the way down to the spine. The shoulder blades were exposed, and we could clearly see tendons and nerves (which must be hard to digest) everywhere. You could stick your hand in between the shoulder blades all the way down to the spine - there was just nothing there.
Another cat had maggots infest its feces covered perianal region and begin burrowing forward. Although the maggots began in that location, they had soon eaten through to the upper back and the abdomen. Since, for some reason, the anus was still intact, we tried to save the cat - if we could kill and/or remove the maggots, most of the destroyed area would regenerate. However, when a bowel movement emerged from the top of the cat’s back instead of its anus, we euthanized it, as obviously the colon had been destroyed.
I would get more descriptive, but bringing the images of what I’ve seen to mind is turning my stomach. It’s spring here, and we expect to see our first maggot cases pretty soon. It is one of the most unpleasant aspects of veterinary work. ::shudder:: (unpleasant doesn’t begin to describe it - I’ve cried and vomited while trying to remove maggots from an infested animal.)
I don’t know for sure, but I suspect that whatever digestive enzyme the maggots secrete also contains an anesthetic, since the animals don’t seem to be in the sort of pain you would expect from seeing the damage.
Make no mistake about it - maggots are a serious problem in tropical and subtropical areas, and can certainly kill in a horrifying manner. I imagine that if you investigate the lives of the poorer inhabitants of the tropical and subtropical regions of the world, or talk to a few military veterans who have fought in these areas, you’ll find that maggots are a serious problem indeed.
Some days you’re the dog, some days you’re the hydrant.