how long does a dead animal have a living virus/bateria in its body? If a animal/human dies of a disease, what causes the disease to die?
I put “virus survive dead animal” into Google and got the following (among others).
It looks like there’s been a lot more research done on rabies than anything else.
You can search some more, if you want.
If by the second half of your question you mean, “Why does the virus die?”, it dies because its host organism is dead. A virus is a kind of parasite. The ones that can survive when dried on cloth are just waiting until another host comes along that they can infect and then live on (and in).
Same thing with bacteria. They usually can only live in one certain kind of environment, like inside a dog’s body, and when the dog dies, the bacteria’s perfect environment disappears.
WAG - pick it apart.
That depends largely on the environment. If the environment is harsh enough (say, in Antarctica buried under a thick layer of snow and ice) there will probably be no living virii or bacteria on or in the body in a matter of hours. If the environment is friendly (say, the Amazon) bacteria would be present until there is no longer a source of food, possibly until totally decomposed.
Again, it depends on the disease. Cancer would die, like healthy tissue, from a lack of nutrients normally supplied by the blood. Virii and bacteria would die due to lack of nutrients or harsh environment, whichever came first. How fast either of those condition occur depends on many different factors.
[slight topic diversion]
FYI: Drugs can stay in deceased animal tissue for quite some time, also.
Case in point: we had a situation in northeast Florida some time ago where Bald Eagles were turning up stupored or dead. Tests and necropsies on the eagles showed high levels of barbituates. Turns out, euthanized animals (either from a shelter or vet, I do not have the article in front of me) were taken to a landfill without being cremated first, as per state law. Eagles, being scavengers, were consuming the euthanized animals and were poisoned by the euthanizing agents. As I recall, the company in question paid quite a hefty fine.
[/slight topic diversion]
On the question of diseases surviving after a human victim’s death:
One of biggest factors in the spread of the Ebola virus is touching of the dead body. The virus had the good fortune to appear in a place where family members customarily wash the corpse before burial. Tragically, Ebola would thus wipe out entire families. This custom was changed as a precaution, and the virus’s spread was drastically cut.