Three years ago, a rash of intestinal illnesses spread across ten indigenous villages in Canada’s far North. Now, researchers from the McGill University Health Centre reported a surprising discovery: the cases were caused by an intestinal parasite that is common in the tropics, known as Cryptosporidium.
“We were very surprised to discover this strain of Cryptosporidium in the Artic, which is more typically seen in low-income countries than elsewhere in North-America,” says the study’s senior author, Dr. Cédric Yansouni, Associate Director of the J.D. MacLean Centre for Tropical Diseases at the MUHC and Professor of the Division of Infectious Diseases in the Department of Medical Microbiology at McGill University.
The researchers say the discovery, which was documented in the journal PLoS Neglected Tropical Diseases, might have long-term implications for the health of children in Nunavik and Nunavut’s communities.
We are being particularly vigilant because it is known in low-income countries that repeated Cryptosporidium infections can cause growth delays and difficulty at school in children. In the Nunavik outbreak, children under the age of five were the group most affected by the infection
“We are being particularly vigilant because it is known in low-income countries that repeated Cryptosporidium infections can cause growth delays and difficulty at school in children. In the Nunavik outbreak, children under the age of five were the group most affected by the infection,” said Yansouni.
Researchers from the Parasitology Laboratory of the McGill University Health Centre investigated the occurrence of cryptosporidiosis that had an onset between April of 2013 and April of 2014. They found Cryptosporidium was identified in stool of 51 of 283 individuals, with the highest incidence rate occurring amongst those aged five or less.
The researchers could identify no common food or water source as causing the infection, but note that Cryptosporidium spp. had been previously detected in ringed seals, bearded seals and blue mussels in Nunavik, making food-borne transmission through the consumption of marine animals one possible route of infection.
Cases were identified in 10 of the 14 Inuit villages in Nunavik during the study period, each of which had separate water sources.
The study says the temporal and geographic distribution of cases suggests anthroponotic rather than zoonotic transmission, meaning it was likely passed along by humans, not animals. The researcher note that certain subtypes of Cryptosporidium have previously been reported in Ontario and British Columbia , but never in Arctic ecosystems.
Nunavik, which comprises the northern third of Quebec is the homeland of the Inuit there. According to a 2011 census, 90 per cent of its 12,090 inhabitants were Inuit.