What's killing sea otters? Parasite strain from cats

Genetic link found between deadly pathogen and wild and feral cats on land

Date: August 22, 2019

Source: University of California - Davis

Many wild southern sea otters in California are infected with the parasite Toxoplasma gondii, yet the infection is fatal for only a fraction of sea otters, which has long puzzled the scientific community. A new study identifies the parasite's specific strains that are killing southern sea otters, tracing them back to a bobcat and feral domestic cats from nearby watersheds.

The study, published this week in the journal Proceedings of the Royal Society B, marks the first time a genetic link has been clearly established between the Toxoplasma strains in felid hosts and parasites causing fatal disease in marine wildlife.

The study builds on years of work by a consortium of researchers led by the UC Davis School of Veterinary Medicine's Karen C. Drayer Wildlife Health Center and the California Department of Fish and Wildlife (CDFW). The scientists were called upon in the late 1990s to help decipher the mystery when Toxoplasma caused deaths in sea otters along the California coast.

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A Parasite Spread by Cat Poop Is Infecting (and Probably Killing) Whales in Canada

By Brandon Specktor, Senior Writer | October 18, 2018 02:32pm ET

Whales have it hard. For a century, they were hunted to a mere fraction of their preindustrial populations, and they now face constant threats from pollution, climate change and ongoing human meddling in the planet's waterways. It's a lot for a cetacean to worry about, and now, according to recent research, whales can add "cat poop" to their list of concerns.

In the new study, published online Sept. 27 in the journal Diseases of Aquatic Organisms, a team of marine researchers from Canada tested the brain and heart tissues of 34 beluga whales. The animals died in Quebec, Canada's St. Lawrence Estuary between 2009 and 2012. The researchers were looking for parasites — in particular, Toxoplasma gondii. This single-celled parasite is commonly found in cats and is notoriously good at spreading to other animals, usually through feces. The team found that 15 of the whales (about 44 percent of the samples) tested positive for T. gondii.

Still, these findings don't prove that the whales died from this parasite, study co-author Stéphane Lair, a professor of veterinary medicine at the Université de Montréal, told the CBC. Rather, "it means [that the parasite was present] either in their heart or their brain." 

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Cat parasite found in western Arctic Beluga deemed infectious

Date:

February 13, 2014

Source:

University of British Columbia

Summary:

Scientists have found for the first time an infectious form of the cat parasite Toxoplasma gondii in western Arctic Beluga, prompting a health advisory to the Inuit people who eat whale meat.

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Common Parasite May Trigger Suicide Attempts: Inflammation from T. Gondii Produces Brain-Damaging Metabolites

ScienceDaily (Aug. 16, 2012) — A parasite thought to be harmless and found in many people may actually be causing subtle changes in the brain, leading to suicide attempts.

New research appearing in the August issue of The Journal of Clinical Psychiatry adds to the growing work linking an infection caused by the Toxoplasma gondiiparasite to suicide attempts. Michigan State University's Lena Brundin was one of the lead researchers on the team.

About 10-20 percent of people in the United States have Toxoplasma gondii, or T. gondii, in their bodies, but in most it was thought to lie dormant, said Brundin, an associate professor of experimental psychiatry in MSU's College of Human Medicine. In fact, it appears the parasite can cause inflammation over time, which produces harmful metabolites that can damage brain cells.

"Previous research has found signs of inflammation in the brains of suicide victims and people battling depression, and there also are previous reports linking Toxoplasma gondii to suicide attempts," she said. "In our study we found that if you are positive for the parasite, you are seven times more likely to attempt suicide."

The work by Brundin and colleagues is the first to measure scores on a suicide assessment scale from people infected with the parasite, some of whom had attempted suicide.

Continued:  http://www.sciencedaily.com/releases/2012/08/120816170400.htm

Good News: Your Cat Won't Give You Brain Cancer

Cat owners are no more likely than people without pets to have brain cancer, a new study finds.

If you're wondering whether you should be relieved as a cat owner or confused as to what Fluffy the Persian has to do with brain cancer at all, we're here to help. The story starts last year, when researchers released a study in the journal Biology Letters finding that infection with a parasite called Toxoplasma gondii may be linked to brain cancer in humans.

T. gondii can live in a variety of mammals and often infects mice. But to reproduce, it needs to get into a cat's gut. It seems to do so by giving its mouse hosts an uncanny bravery around the smell of cat pee, presumably making it more likely that the mice get eaten.

Read on:  http://www.livescience.com/22580-cat-brain-cancer-t-gondii.html

Cat Parasite Linked to Suicide Attempts in Humans

Women infected with the cat parasite Toxoplasma gondii are more likely to attempt suicide than non-infected women, new research finds. The reason for this connection, however, remains mysterious.

T. gondii is a protozoa that prefers to infect cats, but can make its home in any warm-blooded animal. Humans can pick up the parasite from contact with cat feces, or by eating undercooked meat or unwashed vegetables. Once ingested, T. gondii can make a home for itself inside the brain and muscle tissues, protected inside cysts that are resistant to attacks by the host's immune system.

Some studies have linked infection by this parasite with a variety of mental health and brain problems, including schizophrenia, neurosis and brain cancer. But scientists aren't clear on whether the parasite contributes to these problems or is a mere side effect. Someone with schizophrenia, for example, might struggle to keep up good hygiene, meaning the mental disorder could increase the risk for infection.

Read more:  http://www.livescience.com/21345-t-gondii-parasite-suicide-attempts.html