What Makes a Feline Fatal in Toxoplasma gondii's Fatal Feline Attraction? Infected Rats Choose Wild Cats

Toxoplasma gondii is an indirectly transmitted protozoan parasite, of which members of the cat family (Felidae) are the only definitive hosts and small mammals such as rats serve as intermediate hosts. The innate aversion of rodents to cat odor provides an obstacle for the parasite against successful predation by the feline definitive host. Previous research has demonstrated that T. gondii appears to alter a rat's perception of the risk of being preyed upon by cats. Although uninfected rats display normal aversion to cat odor, infected rats show no avoidance and in some cases even show attraction to cat odor, which we originally termed the Fatal Feline Attraction. In this study, we tested for the first time whether the Fatal Feline Attraction of T. gondii-infected rats differed according to the type of feline odor used, specifically whether it came from domestic cats (Felis silvestris catus) or wild cats-cheetahs (Acinonyx jubatus) or pumas (Felis concolor). In two-choice odor trials, where wild and domestic cat odors were competed against one another, consistent with previous findings we demonstrated that infected rats spent more time in feline odor zones compared with uninfected rats. However, we further demonstrated that all cat odors are not equal: infected rats had a stronger preference for wild cat odor over that of domestic cats, an effect that did not differ significantly according to the type of wild cat odor used (cheetah or puma). We discuss these results in terms of the potential mechanism of action and their implications for the current and evolutionary role of wild, in addition to domestic, cats in transmission of T. gondii.