[...] the mite responsible for the extreme hair loss seen in "chupacabras syndrome" is Sarcoptes scabiei, which also causes the itchy rash known as scabies in people. Human scabies is an annoyance, but not usually a serious health or appearance problem, partly because our bodies are already virtually hairless and partly because the population of mites on a given person usually is relatively small---only 20 or 30 mites.
Humans have likely evolved natural defenses for this mite over the years. When we began to domesticate dogs, we likely spread the mites to them. When the mites then transfer to wild dogs, such as foxes, wolves and coyotes, the victims appear to be less able to fight them off.[...]
In these unfortunate animals, large numbers of mites burrowing under the skin cause inflammation, which results in thickening of the skin. Blood supply to hair follicles is cut off, so the fur falls out. In especially bad cases, the animal's weakened condition opens the door to bacteria that cause secondary skin infections, sometimes producing a foul odor. Put it all together, and you've got an ugly, naked, leathery, smelly monstrosity: the chupacabras.
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