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Cat parasite reaches Arctic beluga whales

by Lindsay Jolivet Mar 3 / 14

Researchers have found the parasite Toxoplasma gondii, present in cat feces and kitty litter, infecting Arctic beluga whales for the first time, prompting new investigations to determine if climate change is contributing to the emergence of common food-borne pathogens in the North.

The parasite toxoplasma gondii has been detected in Arctic beluga whales for the first time. Photo courtesy of Neil Fisher and the Vancouver Aquarium

Mike Grigg, a Fellow in the program in Integrated Microbial Biodiversity, presented his team’s findings at the annual meeting of the American Association for the Advancement of Science. Grigg, an investigator at the National Institutes of Health, says that this cat parasite, which is common in temperate climates, has found its way into waterways and into the bodies of about 14 percent of western Arctic beluga whales, which are an important traditional staple of Inuit diet.

While about a third of humans are chronically infected with T. gondii, often through cleaning up after pet cats, the icy Arctic environment was thought to limit the risk of exposure to this parasite in the North.

“Ice is a significant ecological barrier for the transmission of pathogens,” Grigg says.

Now, Grigg says researchers are concerned that as ice in the Arctic continues to melt, more and more whales could be infected by this parasite, especially if cat density increases among Inuit communities or the Arctic lynx moves further north.

“If you bring cats into an environment it increases your risk of getting toxoplasmosis,” Grigg says.

The parasite is highly infectious, and chlorine alone is not enough to kill it in water supplies. In meat, the pathogen is killed when it is frozen or cooked thoroughly. While healthy people don’t usually show symptoms of infection, the parasite is dangerous for pregnant women and those with an immune deficiency such as AIDS. T. gondii is the world’s leading cause of infectious blindness, it can lead to encephalitis in AIDS patients, and cause congenital disease in babies or miscarriage.

“A risk assessment should be carried out to determine if this has any implications for food security,” Grigg says, adding that the public health message to all communities, Arctic or otherwise, is to ensure that whale meat is either cooked or dried properly to kill the parasite.

“Climate change is ushering in a new normal, it’s changing transmission patterns and infectious pathogens will take advantage of that.”

Grigg has also pinpointed a new strain of another parasite, named Sarcocystis pinnipedi, that killed 406 grey seals, or 20% of the population, on Hay Island off Cape Breton in 2012 as well as some sea lions, walruses and bears. That pathogen, while it isn’t a danger to people, is an Arctic parasite that is taking advantage of the rapidly changing climate to spread South to infect a susceptible population of North Atlantic pinnipeds.

Going forward, Grigg says he will work with CIFAR Senior Fellow Curtis Suttle to probe for parasite DNA signatures in water samples to better understand how pathogens are spreading to and from the Arctic, impacting the lives of marine mammals who have never encountered these parasites before.

“Through the course of history, what we’ve found is that pathogens, when they move into a new environment, can actually wreak havoc.”

Animals with no prior exposure to pathogens have no immunity, which means they are biologically unprepared to fight off infection.

“One of the best examples of this, for all of us is to think of, is the Black Plague,” Grigg says.

Video courtesy of the University of British Columbia: