The four sea otter deaths were caused by an uncommon strain of parasites that pose a risk to humans

The Effect of Infection on the Evolution and Behavior of Wild Wolf-Boats: A Case Study of Toxoplasma gondii

The team looked at 256 blood samples from 229 wolves, which had been carefully watched throughout their lives, and had their life histories and social status recorded. Meyer and Cassidy found that infected wolves were 11 times more likely than uninfected ones to leave their birth family to start a new pack, and 46 times more likely to become pack leaders — often the only wolves in the pack that breed.

The parasite, Toxoplasma gondii, makes its hosts bold — a mechanism that increases its survival. To reproduce sexually, T. gondii needs to reach the body of a cat. It becomes more and more likely if the host is changed by the parasites. Research results are mixed, but in rodents, infection generally correlates with decreased fear of cats and increased exploratory behaviour. testosterone and dopamine production are increased in people due to more risks taken.

Warm-blooded mammals can catch the parasite by eating an infected animal or ingesting forms of T. gondii shed in the faeces of infected cats. Semi-dormant cysts form in the brain and muscles after a period of illness, lasting for the rest of your life. Up to one-third of humans might be chronically infected.

The study provides compelling evidence that pathogens can have a profound impact on the ecology and behavior of wild animal populations, according to Dan Macnulty, a wolf biologist at Utah State University. He adds that it demonstrates the immense value of the long-term study of wolves and other wildlife in Yellowstone National Park.

“We got that result and we just open-mouth stared at each other,” Meyer says. “This is way bigger than we thought it would be.” The work is published today in Communications Biology.

Source: https://www.nature.com/articles/d41586-022-03836-9

A study of a rare strain of Toxoplasma gondii in otters and other coastal aquatic animals reveals its discovery as a complete surprise

For Meyer, the moral of the story is that parasites can be major players in ecosystems. “Parasites might have a much larger role than anyone generally gives them credit for,” he says.

Researchers called the finding a “complete surprise” because this strain of T. gondii had never been reported in any aquatic animal or in coastal California. The study was conducted by researchers from the California Department of Fish and Wildlife and the University of California, Davis.

“Since Toxoplasma can infect any warm-blooded animal, it could also potentially cause disease in animals and humans that share the same environment or food resources, including mussels, clams, oysters, and crabs that are consumed raw or undercooked,” Melissa Miller, a California Department of Fish and Wildlife researcher and author of the paper, said in news release.

Miller said, “We want others to be aware of our findings, quickly recognize cases if they happen to encounter them and take precautions to prevent infections.” We encourage others to take extra precautions if they see fat deposits in marine animals.

Most people infected with T. gondii have no symptoms and aren’t aware of their infection, but severe toxoplasmosis can cause damage to the brain, eyes and other organs, according to the US Centers for Disease Control and Prevention. It can be transmitted from mother to fetus during pregnancy and can lead to significant health problems after birth. Babies who were born to mothers who had infections during or shortly before their pregnancies are at higher risk for serious infections.

The CDC recommends food safety practices such as cooking foods to a high internal temperature, rinsing fruit and vegetables, and washing utensils to prevent a toxoplasmosis infection.

The CDC wants people to keep their cats inside, change their litter box every day, and wash their hands well because cat feces is known to contain a high amount of the parasites.

In the study, the researchers said more work is needed to investigate habitat or climate change factors that may have led to the spread of the rare strain in otters, and to examine whether other aquatic wildlife are infected.