Parasite T. gondii now found in Nunavut beluga and narwhal: new research
Parasite prevalent in cats shows up in Arctic wildlife
OTTAWA—The potentially harmful toxoplasma gondii parasite is present in the eastern Arctic’s beluga, narwhal, ringed seals, geese and clams, as well as in many people from Nunavut and Nunavik, according to new research presented at this week’s ArcticNet conference in Ottawa.
You can’t see the dangers posed by toxoplasmosis, caused by the T. gondii parasites, but the infection is powerful enough to make you sick and even cause damage to the brain, eyes and other organs.
Some 28 per cent of people in Nunavut and 60 per cent in Nunavik have been exposed to the T. gondii infection, according to a presentation by Brent Dixon, a research scientist with Health Canada, on Wednesday, Dec. 12.
Such infections are fairly common among people worldwide. Global prevalence is estimated to be about 30 per cent, while Health Canada says that anywhere between 15 and 85 per cent of adults have chronic infections of the parasite, depending on where they live. But higher prevalence is usually found in hot, moist regions, rather than cold, dry ones.
Researchers have previously suggested that the high infection levels in Nunavik are associated with drinking water from home water tanks where T. gondii parasites remain, clinging to the walls—so cleaning of these water tanks could be one way to reduce infection.
But T. gondii remains largely a “food-borne parasite” in people, said Dixon.
Toxoplasmosis is usually spread by cats, the only hosts that can excrete T. gondii. But in the Arctic, Arctic foxes may become infected with T. gondii by eating infected geese. They appear to have spread the parasite to other Arctic animals, including polar bears, muskoxen, caribou, black bear, dogs, wolverines and ptarmigan.
Now T. gondii seems to be present in Arctic sea-dwelling creatures too, because T. gondii has also been found in beluga and narwhal in Nunavut.
Beluga from the Nunavut communities of Sanikiluaq and Arviat were tested for T. gondii, Dixon said.
Of the 16 beluga tested, more than a third tested positive for T. gondii. Similarly, about one-third of the 205 blood samples from narwhals tested positive for T. gondii.
While T. gondii has been reported in a variety of Arctic animals, Dixon said this is the first report of T. gondii in beluga and in narwhal.
He said the research findings were shared with the Government of Nunavut in March so the GN could incorporate this into fact sheets. For now, information on toxoplasmosis does not appear on this list of fact sheets available online.
While toxoplasmosis infection among people is harmless in most cases, 10 per cent of people develop flu-like symptoms or more serious eye problems that can lead to blindness.
Infections can also prove fatal to unborn fetuses and to people and animals with weakened immune systems.
And some research suggests that human infection with T. gondii may be a risk factor for psychological health problems, including bipolar disorder and schizophrenia.
There’s a potential risk of infection to people when eating fresh raw meat and organs, although the presence of T. gondii hasn’t been tested for yet in the blubber of beluga or narwhal.
Dixon said pregnant women and anyone with weakened immune systems should freeze (for at least three days) or thoroughly cook animal meat, blubber and organs of beluga and narwhal before eating them.
He also said to thoroughly wash work surfaces, knives and utensils after handling raw meat or blubber.
His public health message remains that “country foods are safe and nutritious for most people and have cultural significance.”
As well, in a Dec. 12 presentation on diseases that involve people, animals and the environment, Emily Jenkins from the University of Saskatchewan talked about how Canada and snow geese can transmit T. gondii, if eaten raw.
Samples from Inukjuak showed muscles and gizzards, along with other bird parts carried T. Gondii.
About half of those interviewed said they ate it raw and did not freeze it for the recommended 72 hours first, but few knew about toxoplasmosis.
Another study reported on at the ArcticNet conference looked at 124 tissue samples from 81 seals from Nova Scotia to the eastern Arctic, examining these for T. gondii. It found about 25 per cent of the ringed seals in Inukjuak and Salluit were infected with the parasite.
Clams were also recently tested from Red island and Apex near Iqaluit for T. gondii in yet another study: it found four of 125 clams near Apex were infected, as were six of 87 near Red Island.