Well the river does have a few biting animals. There's the dreaded piranha! Actually they've got a bad reputation based on TV and the movies. I swim in every river at every opportunity and have never been bitten. I certainly wouldn't swim with an open wound though - why tempt fate? The worse damage I've seen inflicted by a piranha has been restricted to a missing toe or finger.

There's also cayman in the rivers. These are the smaller, generally docile version of the alligator and crocodile and they usually run on sight.

There are snakes in the forest. Long boots and generally being observant and careful is usually enough to avoid them. It's rare to encounter a snake, not only due to their camouflage, but they run at the sight of people too.

The worst animal is the mosquito. Usually the mosquito and his/her whole family goes to dinner at once, normally at sunset and some hang around all night long.

Nas.