Those animals may well kill and injure much more people than sharks. Around here some people suffered severe abdominal wounds because they found it so cute that the deer rubbed against them.



Actually species like the bull shark roam freshwater too. Jeremy Wade did an episode about that. The episode also featured a horse that has been bitten and almost drowned by a shark well inland in a river.
It may be good to avoid splashing around and not wear anything in yum yum yellow in the water.
I personally prefer to carry small knives in potentially shark infested rivers. It´s much easier to escape to the banks when the blades does not get caught by your legs.