A parasite found in cat feces is showing up in Arctic beluga whales, one of the most graphic examples of the world's changing ecosystems, scientists said.
The finding, announced Thursday, comes with a warning for Inuit residents who eat whale meat. The cat parasite, known as Toxoplasma gondii, is infectious.
Toxoplasmosis, also known as "kitty liter disease" is the leading cause of infectious blindness in humans. It can be fatal to fetuses and people and animals with compromised immune systems.
How the parasite made its way into western Arctic Belugas is still under investigation, say scientists Michael Grigg and Stephen Raverty, with the University of British Columbia.
But they strongly suspect that carrier animals, once separated by ice sheets, are now mingling in common waters, a consequence of widespread Arctic melting.
"It's an unprecedented opportunity for pathogens to shift into new environments," Grigg, a molecular parasitologist with the U.S. National Institutes of Health, told reporters at the American Association for the Advancement of Science meeting in Chicago.
"With ice sheets melting, you're getting more mixing of animal species," he said.
South of the Arctic, toxoplasma -- so hearty it can live in pure bleach -- is quite common and usually harmless. Scientists say its appearance in the Arctic is a worrisome sign of a fast-changing ecosystem.
Grigg said it is possible that pet cats kept by the Inuits are the source of the parasite. The more likely explanation, however, is that the parasite was transmitted in water runoff from lands to the south and spread north in host animals that came into contact and were consumed by belugas.
The whales used in the study did not die from the parasite. They were hunted and harvested by the Inuits. But the introduction of a new parasite into a susceptible population can wreak havoc, Grigg said.
For example, a parasite known as Sarcocystis, previously found only in the Arctic, is responsible for killing 406 grey seals in the north Atlantic in 2012, Grigg said.
The new strain of the parasite, now named Sarcocystis pinnipedi, also has killed an endangered Steller sea lion, seals, Hawaiian monk seals, walruses and polar and grizzly bears in Alaska south to British Columbia, he said.