Curiously, as as new study published in PeerJ finds, T. gondii may also change humans’ physical appearance. An international team turned up a link between a latent infection and facial attractiveness. The researchers recruited 213 healthy college students at the National Autonomous University of Mexico, all of whom had previously been tested for T. gondii. Thirty-five subjects (22 men and 13 women) had the parasite, while 178 (86 men and 92 women) did not. The researchers then asked the subjects various questions and took pictures of their faces.

Next, another 205 participants each viewed a random collection of twenty of these pictures, ten of Toxoplasma-positive subjects and ten of Toxoplasma-negative subjects, rating each pictured participant for facial attractiveness and perceived health on a 10-point scale. (Raters were not told of participants’ Toxoplasma status.) Overall, raters judged Toxoplasma-positive subjects to be significantly more attractive and healthy-looking than Toxoplasma-negative subjects.