Disease experts tracking tropical parasite in the Arctic

“Compared to southern Canada, it’s over 250 times the expected number”


Dr. Cedric Yansouni inside the McGill University Health Centre in Montreal. (PHOTO BY DAVID MURPHY)

Dr. Cedric Yansouni inside the McGill University Health Centre in Montreal. (PHOTO BY DAVID MURPHY)


MONTREAL — Three years ago, a couple of patients in Nunavik had intense diarrheal infections — bad enough for infectious diseases specialists to pay attention.

Turns out it was a tropical bug they caught, usually found in developing countries in Africa or South America. But they caught it in Nunavik.

“Our reaction was surprise,” said Dr. Cedric Yansouni, who specializes in infectious diseases at the J.D. MacLean Centre for Tropical Diseases at McGill University.

The infection was caused by a parasite called cryptosporidium and three years ago, an outbreak of the parasite occurred in Nunavik.

During 2013 and 2014, researchers found 69 cases of cryptosporidium in Nunavik.

“So compared to southern Canada, it’s over 250 times the expected number,” Yansouni said.

“But we strongly suspect this is an underestimate of the total number of infected people. Because only the sickest people presented for care had specimens sent [for testing],” Yansouni said.

The bug was also found in Nunavut, a few years before the Nunavik outbreak.

Cryptosporidium — or crypto for short — displays itself with the same symptoms as normal diarrhea, except that a crypto infection can make people very ill for a prolonged period, especially people with suppressed immune systems or young children, who are more prone to diarrheal infections because of poor or infrequent hand-washing.

However, what makes crypto particularly worrisome is that repeated infections in developing countries have been known to cause long-term impacts on children’s cognitive development.

There’s one drug that’s proven to treat cryptosporidium but it’s not typically available in Canada except in special circumstances, Yansouni said.

So, should parents in the Arctic be worried about cryptosporidium in their kids?

“When I speak about it, people really get worried and panicked.

“I want to be clear. We don’t know if this is happening. But we think the conditions for this to happen seem to be present.

“In other places in the world where repeated infections with parasites like cryptosporidium are common, these infections are strongly linked to stunting and decreased cognitive performance. But those are places that differ from the North potentially,” Yansouni said.

“You can’t necessarily say: well it’s happening in Africa so it will be happening up North. But you can say, you know what? We need to look into this.”

Until recently, laboratories weren’t even looking for crypto in northern patients because it’s typically transmitted through contact with livestock, or farm animals, in developing regions in Africa, for example.

In those regions, food insecurity — which is worse than in the Arctic — and other infections that are not found in the North, along with nutrient deficiencies, aid the parasite’s transmission.

It’s unknown how crypto even made its way up to the Arctic in the first place.

The type of crypto strain in the Nunavik outbreak can only be transmitted between humans, “so the presumption is that it was brought by a human,” Yansouni said.

Yansouni said he’s also not sure whether the infection is newly introduced, or whether it was always in the Arctic, “and we just didn’t recognize it because of limitations associated with diagnostic testing in remote places.”

The bug was actually first found in Nunavut by University of British Columbia infectious disease doctor David Goldfarb, and he published his findings in a 2010-11 study.

Goldfarb and his team found out about crypto in the North by testing very broadly “because we realized there hadn’t been any studies of what’s really going on in terms of diarrhea in the North.”

“So we basically put together everything that we thought theoretically could be up here and we included it in the panel,” Goldfarb said.

Goldfarb published another study in 2013 which found that of 86 samples tested, 17 — or 20 per cent — contained cryptosporidium.

“It’s amongst some of the highest you’d see reported worldwide,” Goldfarb said.

Goldfarb said the strain of crypto his team found was different than the strain Yansouni found; he found the strain that’s transmitted through animals.

Goldfarb and his team are now undertaking a more controlled study to learn more about those infected: their ages, symptoms, where they’re from and when they contracted the parasite, for example.

“That will also help us get more information about cryptosporidium as well as other pathogens,” Goldfarb said.

Goldfarb and Yansouni are also teaming up and tracking children for two years in Kuujjuaq and Iqaluit.

Part of that study, sponsored in part by ArcticNet, will be to examine growth outcomes in children.

Yansouni won’t have results until 2018. But he’ll be working closely with public health departments in Nunavut and Nunavik, disclosing relevant information as necessary.

Yansouni is also helping to facilitate another project to offer a special kind of local testing, rather than having to send samples to southern labs.

He calls the study the largest “in its kind that has ever been done in the North.”

His team has implemented on-site molecular testing in Kuujjuaq to test for things such as cryptosporidium. The testing can also detect other infections which impact the bowels.

“It takes something like an unexpected situation or an outbreak sometimes to make you realize — there is a better way of doing things,” Yansouni said.

“By bringing this on site in Kuujjuaq we’re going to drastically reduce the amount of time it takes to get a specific diagnosis. So people are going to go from having a diagnosis in two weeks or more to having the same day answer,” Yansouni said.

Having same-day answers helps doctors hook patients up with the right treatment and minimizes transmission in households and schools.

“Hopefully in a very short time — within a couple months we’ll be offering this to patients as a first line test,” Yansouni said.

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