A potentially deadly strain of streptococcal infections that contributed to the deaths of 10 people in northwestern Ontario doesn't pose a widespread threat, the province's chief medical officer of health says.

"It doesn't seem to be showing and spreading throughout the community [in Thunder Bay], but spreading within a very specific subgroup of the community," Dr. David Williams said.

Group A streptoccal infection may cause a range of symptoms:
  • No illness
  • Mild illness (strep throat, scarlet fever and rheumatic fever or a skin infection such as impetigo that results in pustules and yellow, crusty sores)
  • Severe illness (necrotizing faciitis, also called flesh-eating disease; streptococcal toxic shock syndrome)
Sources: Public Health Agency of Canada, U.S. Centers for Disease Control

Doctors have treated 75 people with Group A streptococcal infection in the Thunder Bay area since August 2007.

The outbreak seems to be concentrated in a group of homeless people and intravenous drug users, Williams said Thursday.

"For the province [at large], I would say no, it's not a big concern."

Most infections minor

About half of the cases involved the M-59 strain, which has been moving east from British Columbia since 2006.

The strain is linked to more than 300 cases across Canada, said Greg Tyrrell, director of Edmonton's National Centre for Streptococcus.

Both Tyrrell and Dr. Don Low, microbiologist in chief at Toronto's Mount Sinai Hospital, said they expect the M-59 strain to keep spreading across the country.

"We've seen it out now for a couple of years out west and now in Thunder Bay, so it wouldn't be surprising that it eventually shows up in southern Ontario and the other eastern provinces," said Low.

This is strep season, but for most people there is no reason to be worried about this strain, the health officials said.

"Most of these infections are going to be minor infections that just cause sore throat or a skin infection, where antibiotics will treat them quite effectively," Low added.

Meanwhile, the widow of Daniel MacMaster, 37, who died in a Thunder Bay hospital with invasive group A streptococcal disease in March, said he showed flu-like symptoms when he first became sick.

"He went to emergency because he really wasn't feeling good at all," recalled Tina McCallum, MacMaster's common-law partner. "They gave him puffers and a note to take some time off work."

MacMaster was one of the 10 who died over the past year.

Health officials in Thunder Bay are working on tracing the close contacts of those infected.

With files from the Canadian Press