Mutated strains of HIV circulating in a Canadian province where HIV rates rank among the highest in North America could be leading to the more rapid development of Aids-related illnesses, according to new research.

The research, published in the scientific journal Aids, was sparked by anecdotal reports from Saskatchewan, where HIV rates in 2016 exceeded the national average tenfold in some areas. Nearly 80% of those infected with HIV in the province are indigenous.

“Some of our physician colleagues in Saskatchewan started to report that they were seeing cases of people being infected with HIV and getting very sick, very quickly,” said Zabrina Brumme, the lead author of the study and a professor at Vancouver’s Simon Fraser University. “It was almost as if there might have been something particularly nastier about the virus.”

Previous research carried out in Japan had explained a similar phenomenon by pointing to resistant strains that had adapted to evade host immune responses. Researchers wondered if the same factors might be at play in Saskatchewan.

Researchers at a laboratory at the BC Centre for Excellence in HIV/Aids – which since 1998 has performed HIV genotyping for virtually all Canadian provinces and territories – compared more than 2,300 HIV sequences from Saskatchewan with data sets from across Canada and the US.

They looked at 70 mutations and found that more than 98% of HIV sequences collected in the province recently had at least one major immune-resistant mutation.

While HIV strains have previously been shown to adapt to their host populations around the world, it often happens so slowly that it is of little concern. “[But] in other cases, it’s happening more rapidly and we do have to worry about it,” said Brumme.

Saskatchewan, where those infected with HIV are predominantly of indigenous ancestry, is one concerning example. “What has happened is that HIV has adapted quite quickly as it has been transmitted throughout the communities of people.”

The mutations don’t make the virus more transmissible, but instead influence how quickly the disease progresses if it is left untreated.

Brumme cautioned those who would limit the findings to indigenous populations. “We want to make it clear that HIV strains in Saskatchewan have the potential to cause more rapid disease, period. It doesn’t matter who you are,” she said. “This isn’t a health issue restricted to a specific group of people, this is news that there’s a pathogen; strains are nastier in this location.”

While concerning, the good news is that HIV treatment is fully active against these strains, said Jeffrey Joy, a researcher with the BC Centre for Excellence in HIV/Aids. “If people get on treatment, they’re going to have the same outcome as anyone else,” he said. “And have the secondary benefit of not passing those strains on to other people.”

Advocates have long sounded the alarm about HIV rates in Saskatchewan, which in recent years have mirrored those of some developing countries. “Most of those people are indigenous people and most of them are getting HIV through injection drug use,” Trevor Stratton of the Canadian Aboriginal Aids Network told the Guardian last year. “Which is tied to trauma, residential school system and that whole history we have in Canada.”

Researchers are now planning to travel to Saskatchewan to spread the news of their results and encourage testing and treatment.

Julio Montaner, the director of the BC Centre for Excellence in HIV/Aids, hoped the findings would help fuel the many calls for action. “These findings add further urgency to addressing the Saskatchewan epidemic, in which the infection burden is concentrated among the most marginalised,” he said in a statement.