How Melting Ice Allowed A 'Kitty Litter' Parasite To Spread to Arctic Whales, Threatening Humans
In 1996, doctors at Johns Hopkins University predicted that a warming climate would shake loose all kinds of diseases previously trapped by cold. Mosquitos, no longer confined to warm latitudes, would venture farther afield, carrying malaria and dengue fever with them. Sea-borne bacteria and toxins would drift through warming oceans, spreading cholera and shellfish poisoning. Even human migration caused by new weather patterns, they said, could "indirectly contribute to disease transmission."
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Now their fears have come true, according to Canadian researchers who say they've discovered a parasite, common among house cats, in western populations of Arctic beluga whales. The disease, called Toxoplasma gondii, and transferred by consuming undercooked meat, can be fatal to human fetuses and can cause eye infections leading to blindness. It is known by the nickname "kitty litter disease."
Of all the consequences of climate change — including drought, intensifying storms, and even, simply, fatal episodes of heat — the spread of pathogens is among the most insidious. "What we're seeing with the big thaw is the liberation of pathogens gaining access to vulnerable new hosts and wreaking havoc," said Michael Grigg of the National Institutes of Health. Grigg is among the researchers at the University of British Columbia who discovered the spread of Toxoplasma to the Arctic whales.
Public health officials have warned the local Inuit people, who eat these whales, to avoid the meat, the BBC reported. According to the University of British Columbia, a 1987 study of 30 women in northern Quebec showed that four of them were exposed to Toxoplasma during their pregnancies. All four gave birth to infected children. The cause was consuming dried seal meat. Grigg and his colleagues also recently discovered a totally new strain of the parasite was responsible for the deaths in 2012 of 406 gray seals in the north Atlantic. This strain is not dangerous to humans; however, it is being blamed for the deaths of "an endangered Steller sea lion, seals, Hawaiian monk seals, walruses, polar, and grizzly bears."
Though how exactly the parasite moved from litter boxes to Arctic whales is a mystery (they think imported pet cats may be the culprit), the fast-paced spread to marine mammals has everything to do with melting sea ice. "Ice is a major eco-barrier for pathogens," Grigg said. Ice sheets were a literal barrier between cold and warm latitudes. As more sheets melt, sea creatures move more freely, conducting diseases to each other.
As a 2011 article in Trends in Parasitology points out, the Arctic is especially vulnerable because of its "low ecological diversity" and "subsistence hunting and inadequate food inspection." According to Stephen Raverty, one of Grigg's colleagues at the University of British Columbia, "Belugas are not only an integral part of Inuit culture and folklore, but also a major staple of the traditional diet. Hunters and community members are very concerned about food safety and security." Around 50,000 Inuit people were living in Canada in 2006.
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