Strep A infection rates surge

Health officials investigating cluster of cases

Faced with surging numbers of severe, invasive group A streptococcus infections across B.C., mystified provincial public health officials are seeking feedback from Canadian and American counterparts and preparing to publish reports to draw attention to the problem.

A soon-to-be-released document will show that in 2016 there were 303 confirmed B.C. cases of invasive Group A streptococcal disease, or iGAS. That equals 6.4 cases per 100,000 population, the highest rate since 1997 when it became a mandatory reportable disease.

Illnesses like scarlet fever, strep throat and impetigo are caused by strep A bacteria — but so, too, is potentially deadly toxic shock syndrome and flesh-eating disease (necrotizing fasciitis). That is what an 11-year-old Richmond boy contracted four months ago when he was one of two boys in the same classroom who got iGAS.

John Chen has been in hospital since March. A classmate was hospitalized a week earlier with different complications from the infection.

It is the first time a cluster of cases has ever been reported to public health officials in Canada, so B.C. experts are now reviewing policies and consulting colleagues to determine whether notifications to parents should go out earlier than they did in this situation, when families got letters only after the second case.

Dr. Monika Naus, a medical director at the B.C. Centre for Disease Control, said experts are unsure how to turn iGAS incidence trends around. In the Vancouver Coastal Health region, there were 47 cases of iGAS, according to the most recent (April) year-to-date report. That compares to 34 the year before.

In 2016, there were 114 cases in VCH, or 9.8 cases per 100,000 population.

That is more than double the average of 47 cases for each of the preceding four years, when the rate was 4.2 per 100,000 population.

The highest number of cases was in Vancouver, with 84. Those affected ranged in age from five to 83.

Naus said she does not think the increase has anything to do with cases being miscategorized because lab confirmation is required. Experts have consulted addiction specialists since injection drug users may be at higher risk of such infections, but “they’ve informed us that injection frequency among users is not thought to be higher than in prior years,” she said.

The symptoms of iGAS include fever, chills, fatigue, vomiting and pain. Naus said the most important piece of advice she can give patients is to seek medical attention promptly when they develop symptoms so they can be prescribed penicillin or other antibiotics.

“The cardinal sign of necrotizing fasciitis is pain out of proportion to the injury,” she said.

Sam Chen, the father of 11-yearold John, said he took his son to a primary care doctor in Richmond when he developed a fever and severe pain in his leg, but he was merely advised to take ibuprofen. Research has shown that such medication could raise the risk of complications in children.

The boy was eventually taken to B.C. Children’s Hospital, where doctors diagnosed necrotizing fasciitis and began the first of 18 operations to save his limbs.

Chen has questioned why Vancouver public health officials did not send a notification letter to parents of children in the classroom until after two cases were identified. He believes the infection is serious enough that parents should have been notified after the first case.

“I know nothing can change the fact my son got so ill, but what is the harm in notifying parents right away, so that they can watch for symptoms and take their children to the doctor or hospital if they see any symptoms?” he said.

Dr. Althea Hayden, a medical health officer with Vancouver Coastal Health, said public health officials don’t want to cause “undue alarm among people who are not truly at increased risk.”

“This was the first recorded case of two children in the same elementary school contracting this illness,” she said.

Hayden said it’s possible cases of iGAS are surging because of more virulent strains, but there is no consensus on that.