by Cristian Solari
Homo sapiens (+) Mutualism (+) Crocuta crocuta
In, Mekelle, Ethiopia, hyenas have a positive mutualistic interaction with humans. They feed on carcass waste left and help sanitize the city. By eating all that waste, hyenas prevent five anthrax and bovine TB infections in humans plus 140 infections in cattle, sheep and goats annually.
Check this link for more information.