北极白鲸体内发现猫类寄生虫

University of British Columbia 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. The same team also discovered a new strain of the parasite, previously sequestered（隐退） in the icy north, that is responsible for killing 406 grey seals in the north Atlantic in 2012.

Presenting their findings today at the 2014 Annual Meeting of the American Association for the Advancement of Science (AAAS), Michael Grigg and Stephen Raverty from UBC's Marine Mammal Research Unit say that the "big thaw" occurring in the Arctic is allowing never-before-seen movement of pathogens（病原体） between the Arctic and the lower latitudes.

"Ice is a major eco-barrier for pathogens," says Michael Grigg, a molecular parasitologist with the U.S. National Institutes of Health and an adjunct professor at UBC. "What we're seeing with the big thaw is the liberation of pathogens gaining access to vulnerable new hosts and wreaking havoc（肆虐）."

Toxoplasmosis, also known as kitty litter disease, is the leading cause of infectious blindness in humans and can be fatal to fetuses and to people and animals with compromised immune systems.

"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," says Raverty, a veterinary pathologist with the B.C. Ministry of Agriculture and Lands' Animal Health Centre and an adjunct professor at UBC. Raverty has led the systematic sampling and screening of hunter-harvested Beluga for 14 years.

Grigg has also identified the culprit of the 2012 grey seal die-off as a new strain of Sarcocystis. While not harmful to humans, the Arctic parasite, which was named Sarcocystis pinnipedi at the AAAS meeting today, has now killed an endangered Steller sea lion, seals, Hawaiian monk seals, walruses（海象）, polar and grizzly bears in Alaska and as far south as British Columbia.