(Keep your cats indoors!)
Is your cat a hot-tempered, unneutered male who spends a lot of time outdoors and seems to like nothing more than scrapping with the other guys in the neighborhood? If so, he's at especially high risk for infection with the feline immunodeficiency virus (FIV), a submicroscopic, parasitic organism that can weaken his immune system and, in time, make him vulnerable to a host of opportunistic diseases.
Deep bite wounds, notes Julie Levy, DVM, PhD, are, by far, the primary mode of the virus's transmission from an infected to an uninfected animal. And pugnacious free-roaming males are more likely, by far, than other felines to bite them.