A parasite Toxoplasma gondii, was long known to have reduced the fear of being hunted in rodents.
However, in a recent study it was found that the fear aversion was not cat-specific.
In a study published in Cell Reports on January 14, shows that the parasite reduces general anxiety in mice and hence makes them more prone to being preyed upon.
Toxoplasma gondii is an intestinal coccidium that parasitizes members of the cat family as definitive hosts and has a wide range of intermediate hosts, according to NCBI. It can also infect humans.
When a person becomes infected with the protozoan parasite, it forms cysts that can affect almost any part of the body, be it brain or the heart, and causes the disease toxoplasmosis.
The report summarizes that the decrease of “felid aversion” induced by the parasite, termed as “fatal attraction”, was interpreted as an “adaptive manipulation” by T. gondii. This earlier assertion was put to test in this study.
The researchers performed a “multiparametric analysis” of T. gondii-induced changes on the host behavior, physiology along with “parasite cyst load and distribution”.
The infected rodents displayed increased curiosity and exploration when put in challenging situations. These were also found to not discriminate between live and inert stimuli. Initial altered sociability result in an “altered ability” to adequately process signals that may represent “potential threats”.
Co-first author of the study Pierre-Mehdi Hammoudi of the University of Geneva said that these results were in “contrast with the prevailing idea” that the T. gondii’s “manipulation of host behaviour” specifically targeted “neural circuits responding to feline predators".
The study can be accessed in Cell Reports.