A “mind-controlling” parasite makes hyenas reckless against lions

Toxoplasma is a parasite that infects about a third of the world’s population and is known for its ability to manipulate hosts, such as lab mice, into becoming reckless. A study published in the scientific journal Nature Communications He found, for the first time, that this same effect can be observed in wild animals.

Researchers have found that hyena dogs are infected with the parasite Toxoplasma They become reckless in the face of lions, their natural predators. In the same way a mouse approaches domestic cats when infected.

Studies show that uninfected hyena chicks were on average 90 meters away from the lions. Those with antibodies against toxoplasmosis reached an average distance of 40 metres. This way, they are four times more likely to be killed. Data were collected in the Masai Mara National Reserve in Kenya.

“This parasite not only affects domestic cats and their prey like mice, but it can be a much more widespread phenomenon,” Kay Holkamp, ​​a behavioral ecologist at Michigan State University and co-author of a new study on the topic told National Geographic on the topic published in the scientific journal. Nature Communications. She has been studying hyenas since 1988.

Attracted by the smell of urine

The parasite can infect many host species, including rodents, birds, and other prey, if you ingest contaminated meat or feces. Over millions of years of evolution, this distant cousin of malaria has come up with an interesting trick: rodents infected with toxoplasmosis find the smell of cat urine irresistibly attractive, and this can bring them closer to hungry cats.

“This phenomenon not only promotes the reconfiguration of the parasite’s genome, but also allows the production of environmentally stable spores that can infect many other hosts,” Zak, a study co-author, explained to National Geographic. Lubach, Postdoctoral Fellow at the University of Colorado, Boulder.

The study is unprecedented and innovative, says Stephanie Johnson, a researcher at the University of Colorado, and believes that the effects observed in hyenas are just one part of a suite of strategies the parasite has to control its hosts, and which may work in other ways we do. Don’t know yet.

“This confirms that Toxoplasma has powerful effects on mammalian behavior. It is a parasite that people think is completely harmless, especially in humans, but when we consider some of the observed effects, Toxoplasma can cause serious effects on human behavior, even on a social level,” he says. researcher.