A potentially fatal illness that swept through 10 communities in Nunavik between 2013 and 2014 has been linked to a parasite normally found in tropical climates.

Researchers with the McGill University Health Centre (MUHC) confirmed the presence of Cryptosporidium, an intestinal parasite more often transmitted through domestic farm animals and recreational waterways.

The discovery of Cryptosporidium in such a northern climate shocked the scientists, who published their findings recently in the journal PLoS: Neglected Tropical Diseases.

They are unsure, though, if this represents a first-time event or if previous transmissions had simply gone undetected.

"We know what we found, and we know that it is unexpected," Cédric Yansouni, associate director of the J.D. MacLean Centre for Tropical Diseases at the MUHC, told CBC's As It Happens.

"But we don't know whether it's new or not."

What this outbreak really brings into focus is many of the obstacles that are faced in northern communities. - Cédric Yansouni, microbiologist

Cryptosporidium is transmitted by eating contaminated food, drinking contaminated water or by coming into contact with infected people. It causes Cryptosporidiosis, an illness that usually manifests itself as several weeks of watery diarhhea.

Most people don't require treatment for Cryptosporidiosis, said Yansouni, it simply runs its course. But it can be fatal among young children or to anyone with a weak immune system.

Challenges of the North

The strain detected in Nunavik was likely introduced by an individual infected elsewhere. But scientists believe that poor living conditions — such as overcrowding — contributed to its spread.

"What this outbreak really brings into focus is many of the obstacles that are faced in northern communities," said Yansouni.

The outbreak likely went undetected for several months because of a lack of diagnostic facilities in Nunavik, he added.

"Issues like overcrowding and rapid diagnosis closer to the patient are key challenges that so far are incompletely met."

The Shoal Lake 40 First Nation, along the the Ontario-Manitoba border, has been under a boil-water advisory since Cryptosporidium was detected in the water in 1997.