This is why Toxoplasma gondii reproduces only in cats

A group of researchers, through a study published in the Public Library of Science Biology, clarifies the mystery about the reproduction of Toxoplasma gondii, a single-celled parasite that mainly infects cats and that on some occasions can be a threat to human fetuses despite the majority of the cases it may be harmless for us.

The Toxoplasma gondii can reproduce mostly only in the intestine of cats although it can infect other animals in which, however, it cannot reproduce. It is thought that this parasite, in addition to being omnipresent in the environment, is found within the body of almost a third of the entire technically infected human population. The parasite enters our body through undercooked meat or food, objects or water contaminated with cat waste.

The only danger that seems to have been ascertained for humans is the transmission to the fetus in pregnant women, which can lead, as demonstrated in certain cases, to serious consequences.
However, the fact remains that most people do not even know they have been infected because this parasite, although it resides in the brain, is harmless to any human being outside the uterus.

For unknown reasons this parasite, when found in the intestines of cats, reproduces in a massive and apparently uncontrolled manner.

According to Laura Knoll, senior author of the study, it is a particular substance, a fatty acid present in the intestines of cats, that is responsible for this abnormal reproduction.