TURKU, Finland — A sexually transmitted parasite carried by up to 50% of the population may actually make people more attractive to the opposite sex. According to Finnish researchers Toxoplasma gondii can be responsible for a number of different neurological disorders, including schizophrenia and psychotic episodes. However, its strangest effect may be to change the way others view people with the infection.
The study authors found that men and women infected with T. gondii were considered to be more attractive and healthier than uninfected individuals. The team say this strange connection could have its roots in evolution, theorizing that changes that benefit the host (an animal or a human) also benefit the parasite. This symbiotic relationship would help the parasite spread through carriers with more sexual relationships.
“In one study, male rats infected with Toxoplasma were perceived as more sexually attractive and were preferred as sexual partners by uninfected females,” writes study first author Javier Borráz-León of the University of Turku and his team in the review. PeerJ.
The parasite can actually change the look of your face
While previous studies on T. gondii suggest that the parasite leads to higher testosterone levels in men, others suspect that the parasite manipulates chemicals in a host’s body, including neurotransmitters and hormones.
Manipulating a host’s “phenotype,” says Borráz-León, can lead to profound changes, including a person’s physical appearance.
“Some sexually transmitted parasites, such as T. gondii, can produce changes in the appearance and behavior of the human host, either as a byproduct of infection or as a result of manipulation of the parasite to increase its spread to new hosts,” the researchers write in their study.
In an experiment including 35 students (22 men, 13 women) infected with T. gondii and 178 students who did not carry the parasite, the researchers examined the symmetry of their facial features. The team explains that fluctuating asymmetry is a measure of how different your facial features are. Studies have linked having more symmetry in your face (decreases levels of asymmetry) to better health, stronger genes, and being more attractive to others.
The results show that participants infected with Toxoplasma had lower levels of fluctuating asymmetry than healthy students. In addition, young female carriers of the parasite had a lower body mass index than their peers. These women also rated themselves as more attractive and reported having more sexual partners.
“It is possible that the apparently non-pathological and potentially beneficial interactions between T. gondii and some of its intermediate hosts, such as rats and humans, are the result of co-evolutionary strategies that benefit, or at least do not harm, to physical fitness. of both the parasite and the host,” the study authors conclude.