More And More TB Cases
Becoming Drug Resistant
TORONTO (CP) -- Tuberculosis, once thought a disease of the past in Canada, is growing increasingly resistant to the drugs used to treat it, suggests a new Ontario government study.
The analysis of TB cases over the last 10 years confirms what many scientists have been warning: there are more and more instances where the infection doesn't respond to certain medication.
A few people have died as a result.
The "ominous" problem exists mainly among immigrants from some countries in Africa and Asia, said Dr. Frances Jamieson of Ontario's public health laboratories, the study's author.
But drug-resistant strains could spread if doctors and public health officials aren't vigilant about detecting and aggressively treating cases, she said.
"We must remain vigilant ... It's not something we can ignore," said Jamieson.
"If you don't do it, the risk of spreading resistant tuberculosis is there."
An outbreak such as occurred in New York a few years ago could lead to "an escalating situation," she said.
While Jamieson's study dealt with Ontario, she said the problem also exists in other cities with large concentrations of immigrants, such as Vancouver and Montreal.
Experts at a conference on tuberculosis in Toronto this week debated whether Immigration Canada's complex rules allowing for some screening of the immigrants for TB need to be tightened, she said.
Jamieson's study looked at 6,655 TB patients from 1987 to 1997 and their reaction to five different drugs.
It found the proportion of cases resistant to isoniazid, one of the most effective treatments, more than doubled to 12.9 per cent over that period.
Resistance to another medication, streptomycin, jumped to eight per cent in 1997 from five per cent in previous years.
About 16 per cent of TB cases occurring in Ontario are now resistant to at least one of the drugs commonly used to treat the infection, she said.
The usual treatment of the disease lasts six months.
Those with resistance to one or more drugs must be treated with a blend of medication. It takes longer for those people to be cured and the cocktail of pills can have unpleasant side effects, Jamieson said.
Resistance has built in certain poor countries because patients go untreated, can afford only one drug or fail to keep taking the pills until the disease is eradicated, said Jamieson.
Others simply won't admit they have it, she said.
"TB has quite a stigma for a lot of cultures so they don't want to say they have TB."
Jamieson said similar problems exist among Toronto's homeless population, where tuberculosis has been spreading lately.
Doctors can keep the problem in check if they're sure to examine patients from high-risk countries for TB, and prescribe the appropriate treatment, she said.