[cloudmountain]

My question was -- how did those ANIMALS get infected?
Eating infected human stuffs?

Hardly. They don't eat feces..no nutrients. Besides there is plenty of food for them in those nutrient-rich forest areas.

[Smokin' Joe]

Fruit bats produce feces which land on fruit and in water, which is consumed by primates also eating the fruit (and possibly even the bats).

The primates and bats are considered food, if not a delicacy by the locals, and either in eating the contaminated meat or in the process of butchering the locals become infected.

It is possible that infection could be caused by tainted fruit or water as well, because the virus survives well outside the host for a while and is excreted in any bodily fluid. Cooking might not be sufficient to kill the virus.