How a parasite that infects wolves turns them into pack leaders

How a parasite that infects wolves turns them into pack leaders

The pathogen responsible for toxoplasmosis influences the behavior of these animals, a study has shown.

What if the infection of a parasite could change the behavior of animals? This is in any case what has just been demonstrated by a study published at the end of November in Nature Communications Biology.

Indeed, after using 26 years of behavioral, spatial and serological data on wolves in Yellowstone National Park, Wyoming, United States, the researchers were able to suggest that the wolves infected with the parasite responsible for toxoplasmosis were more likely than others to become pack leaders.

Infection due to contact with cougars

You should know that wolves infected with toxoplasmosis are at the base through cougars.

But as infected wolves become less fearful than others, they then come into further contact with cougars and retransmit the parasite to the original hosts. The loop continues like this…

Toxoplasma gondii is a protozoan parasite capable of infecting any warm-blooded species and mainly felines (therefore pumas), but it can also be transmitted to wolves and humans.

A parasite that drives risky behavior

The results of published research show that infected wolves adopt a very young riskier behavior than their uninfected counterparts.

Indeed, these infected wolves leave their pack earlier to try to found their own pack. Then they behave more aggressive, more dominantexplaining that they become pack leaders more easily.

Hormonal changes?

The researchers explain that “experimental studies have shown that chronic infections, even in healthy individuals, can lead to increased production of dopamine and testosterone. These chormonal changes can lead to increased aggression and risky behaviors such as increased hyperactive movements, inability to avoid olfactory cues from predators (i.e. seek out rather than avoid urine for Felidae) among others”.

Result infected wolves are more dominant, less afraid and more conquering in particular in breeding.

Benefits for the parasite

The agent is thus transmitted more easily by sexual means, by the fact that the wolves will conquer more distant territories therefore the propagation is wider and as the animal takes more risk it can die more easily and the parasite can thus infect animals that feed on carcasses.

What about humans?

As specified by theNational Health Security Agency (ANSES), this infection is common in France. “About 50% of the adult population is infected usually without noticeable symptoms. It is estimated that 200,000 to 300,000 new infections occur each year. In healthy people, toxoplasmosis is usually mild. The serious forms are above all observed in the event of infection of a mother during her pregnancy and secondary transmission to her fetus (congenital toxoplasmosis) and in immunocompromised patients.

But a curious studypublished on PeerJ last March ensures that infection by this parasite of human beings causes a modification also. And the man or woman who contracted toxoplasmosis would, according to the researchers, become more sexually attractive and would have more sexual partners… All this to allow the parasite to spread more easily in the population.

Even if scientists remain cautious and encourage research on this subject to complete their postulate.

But ultimately there might be some advantages to being infected with a pathogen a few times…

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