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Toxoplasma gondii is sometimes referred to as a “mind control” parasite — it can infect an animal’s brain, disrupt the animal’s behavior, and kill the host. Now, U.S. researchers have found that wolves infected with Toxoplasma gondii may benefit from these mind-changing “tricks.”
The study, published Nov. 24 in Communications Biology, found that being infected with Toxoplasma makes wolves more courageous and more likely to become pack leaders or seek other habitats, which leads to more opportunities for reproduction.
“We really underestimate the consequences of these parasites.” Eben Gering of Nova Southeast University in the United States, who did not participate in the study, said: “These findings may reveal the tip of the iceberg of the dynamic significance of Toxoplasma gondii for wild ecosystems.” ”
Toxoplasma gondii is a single-celled parasite that breeds only in domestic cats and other felines. It has long been known that rodents infected with Toxoplasma gondii lose their fear of predators. Because the brain somehow increases dopamine and testosterone, which in turn enhances the host’s courage and risk-taking.
Jaap de Roode, a biologist at Emory University, said: “These parasites are using some ‘mind control’ or ‘personality control’ to help themselves through their life cycle. This has unpredictable consequences. ”
The consequences are not limited to rodents. In 2016, Gabonese researchers found that captive chimpanzees infected with Toxoplasma gondii no longer abhor leopard urine. Last year, another team of researchers described how hyena pups infected with Toxoplasma gondii in Kenya ventured close to lions.
This time, after learning that some wolves in Yellowstone National Park were infected with Toxoplasma gondii, Connor Meyer, a doctoral student at the University of Montana, teamed up with Kira Cassidy, a biologist at Yellowstone National Park, to study whether the parasite also changed the behavior of wolves.
Researchers have studied gray wolves in the park for up to 26 years, including results from Toxoplasma gondii tests obtained from blood samples taken. They also examined data from mountain lions because Toxoplasma can breed in mountain lions.
It turned out that wolves were more susceptible to Toxoplasma infection in areas with a lot of mountain lion activity. The authors note that the wolves most likely contracted Toxoplasma gondii from mountain lions.
Combining infection data and field observations, the researchers also found that wolves infected with Toxoplasma were more likely to become pack leaders and more likely to leave the pack at a young age in search of new territory or other packs, just as infected rodents became more eager to explore.
“In some cases, wolves and even their colonies may become very successful because they are more willing to take risks and keep pushing boundaries,” Cassidy said. ”
As with rodents, wolves’ adventures come with risks. Wolves that wander around may be more likely to be hit by a car, or leave a protected area and end up being shot by hunters. Infected wolf pack leaders may also transmit parasites during mating, which can be detrimental to pregnancy.
Overall, Cassidy suspects that the risks of infection may outweigh the benefits in the long run. “Wolves live on the edge of life and death as soon as they are born.” (Source: Wang Fang, China Science News)
Related paper information:https://doi.org/10.1038/s42003-022-04122-0