Killer Monkeys

Killer Monkeys are naturally occurring species of primates who were the original carriers of the Red. They are not normally contagious to others species, not even humans, because the strain of Red they carry is the primitive original and lacks the virility of the modified version used by agents of the Darkness. 
Still, explorations into the jungles and remote areas of the world may bring one into conflict with groups of killer primates.
References:
-https://www.youtube.com/watch?v=6nj5G4GffWo