A dangerous parasite spread by domestic cats has been found in beluga whales in the Arctic.

The discovery of Toxoplasma gondii in the marine mammals has led researchers to issue a public health warning to Inuit populations who eat beluga whalemeat in dried strips and stews.

Though cooking the meat destroys the parasite, the infection could be spread when people prepare meals and fail to wash their hands afterwards.

Toxoplasma is one of the most successful pathogens on Earth. The bug infects an estimated third of the world population. In the UK, the Food Standards Agency estimates 350,000 people become infected each year.

The infection is harmless in most cases, but 10% of people develop flu symptoms or more serious eye problems that can lead to blindness. The infection has also been linked to schizophrenia and other bipolar disorders.

Pregnant women are particularly at risk, as the parasite can affect heart and brain development in foetuses, and trigger miscarriages and stillbirths.

Prof Michael Grigg at the University of British Columbia in Vancouver said tests on hundreds of beluga whales in the Beaufort Sea, on the edge of the Arctic, revealed that 14% of the creatures harboured the infection. The tests are the first to show the infection has reached the region.

"This is now emerging in the Arctic and there's not much we can do about that. This is the new normal," said Grigg. The infected whales did not appear ill, but Grigg said that his team might not be finding animals made sick by the infection.

The most likely cause of the outbreak was infected cat faeces washing into waterways and on to the sea, where fish and other marine organisms became contaminated and ultimately eaten by the whales.

Given that water supplies might be contaminated, the Inuit populations have been advised to filter or boil their water to destroy the parasite. The organism is hardy, and will survive immersion in chlorine or sulphuric acid, but can be killed by heat, desiccation or freezing.

The rise in pet cats among the Inuit and a warming climate which helps the pathogen survive until it finds a host could be to blame for the emergence of the infection, Grigg told the American Association for the Advancement of Science meeting in Chicago.

"Ice is a major eco-barrier for pathogens. What we are seeing with the big thaw is the liberation of pathogens gaining access to vulnerable new hosts and wreaking havoc," he added.

Belugas are killed by the Inuit as part of a subsistence hunt and limits are imposed on the catches. Though some populations are endangered, others, such as the 30,000 or so in Hudson Bay, are not. The population in Canadian waters is estimated at 70,000 to 140,000. A single whale can feed 100 people.

"The Inuit's traditional processing and cooking methods should be enough to kill Toxoplasma but vulnerable populations such as pregnant women need to be extra vigilant around handling and consuming raw whalemeat," said Grigg.

In separate work, the same researchers identified a pathogen that caused a mass die-off of grey seals in the north Atlantic in 2012. The parasite, named Sarcocystis, was previously found only in the coldest northern waters. Further tests since have found that the same parasite has killed Steller sea lions, seals, Hawaiian monk seals, walruses, and polar and grizzly bears in Alaska and British Columbia.