Tuberculosis at Sask. mine sparks cross-Canada check of workers

August 26, 2013 - 7:12am
Photo courtesy of paNOW.
Photo courtesy of paNOW.

A case of tuberculosis (TB) at a Saskatchewan mine has led to contact tracing across Canada.

The active tuberculosis was discovered at the Cigar Lake Cameco mine at the end of July and caused the mining company and TB Control Saskatchewan to work together to track individuals possibly exposed to the disease. The latest count showed 130 individuals spread across eight provinces from British Colombia to New Brunswick.

“It's not uncommon. It depends on the situation and depends on what the communicable disease is,” said Deputy medical health officer in the Saskatoon Health Region Dr. Julie Kryzanowski.

“When that happens then there is notification sent out through interprovincial reporting structures to notify them of the potential exposure so they can be alert and do what needs to be done for people who live in their province or their health regions.”

Under the Public Health Act and disease control regulations there are a number of communicable diseases that are reportable by law, including TB. Public health does a follow up to figure out what individuals may have been exposed.  Those people are offered a skin test to see if they have the TB bacteria and are then offered antibiotic treatment.

“If it turns out that one of them does not live in our health jurisdiction then we make contact with the other health region or the other province that they live so that they are aware that they may have been in contact and they can be tested or treated,” Kyrzanowski explained.

“There have not been any confirmed cases of active TB disease as a result of this particular case.”

The initial contact tracing was for 119 people, 105 who reside in Saskatchewan and 14 from out of province. The number has since grown to 130 people.

For most people who become infected with TB it remains dormant. A small amount of people have a 10 per cent lifetime risk of developing active TB and only in those cases is it infectious.

At peak times the Cameco mine can have over 900 employees working on-site, many who recently came to Canada or are from Saskatchewan’s northern communities. Both are populations that tend to be more at risk to develop active TB. Currently, rates in Saskatchewan are higher than national average and 54 per cent are experienced in the north.

“A large part of the TB strategy is addressing communities that have higher risks of TB... we do have a higher incidence in northern communities,” Kyrzanowski explained.

“That's for a lot of reasons historically and currently as well. We know that TB and active TB is really a disease of poverty so there are a lot of conditions in the north, poor socioeconomic conditions, poor housing quality, people living in overcrowded conditions, people that are living in an isolated community and they don't have as much access to health care services as we do in the south. So, for a lot of those reasons it has been harder to get control of TB in the northern communities.”

In other provinces most of the TB cases occur in immigrants from places where TB is more prevalent than in Canada.

“Saskatchewan is facing a challenge with TB from two perspectives. Certainly there is the higher rates of TB from northern communities which we are working hard to address but we are also aware that as Saskatchewan becomes more of a place where newcomers settle, especially with recruitment of international workers, we recognize the newcomer population as potentially being another risk where we may see more cases of active TB disease,” she said

Both of these populations supply workers in the province’s growing resource sector, but current Canadian TB standards do not recommend screening employees for TB infection in workplaces other than health care settings, correctional facilities, and some high-risk residential community settings like shelters and addiction treatment centres. Saskatchewan itself saw 82 new cases in 2011.

“Saskatchewan is certainly undergoing a period of economic growth and companies are recruiting workers from across the province and internationally as well. That's true about sites located in northern Saskatchewan but also sites elsewhere in the province as well,” Kryzanowski said.

Therefore, she explained that having resources based out of the North does not increase the risk of communicable disease but rather tapping into at-risk populations. She saidthe TB strategy recognizes that in order to reduce the risk of a population when entering the workforce it is important to look at pre-determinants of health like nutrition and poverty.

“One pillar of the TB Strategy is… public health prevention and community engagement… addressing social determinants of health. TB spreads more easily when people are living in poor housing conditions, overcrowded conditions, no access to nutritious food and healthcare services,” she said.

Kryzanowski said it is important to continue working on the TB problem, especially as drug-resistant TB emerges as an issue that complicates treatment and can increase costs to $195,078 per patient. Drug resistance can be prevented through early detection and follow-through treatment practices.

One active TB case in Saskatchewan has already affected 130 people throughout eight provinces. Kryzanowski said that the cost has been absorbed by TB Control’s budget and shared with the other affected health regions.

“We don't have an estimate of the eventual future number of contacts to this case and we don't have an estimate of the cost associated with the contact tracing,” Kryzanowski said.

$74 million was spent of fighting TB across Canada in 2004.  That equalled $47,290 for every active TB case diagnosed that year. The cost of TB programming in Saskatchewan is shared between the provincial and federal governments and it is used for treatment, medications, skin test screening, radiographic and laboratory diagnostics, patient incentives, and salaries for the health care workers.

Kryzanowski said that Cameco has likely incurred costs due to this case for helping to bring health care workers in and out of the site and the financial cost of time to gather and supply information to TB Control Saskatchewan. 

“Every case of active TB that TB Control Services follows up is a different situation. In some cases there are a lot of contacts that are identified... it really is a case-by-case basis. Whatever the circumstances are it often requires us to engage with another institution or employer or facility that has a stake in making sure the contact investigation goes smoothly,” she said.

“I would say it’s the norm to work very closely with partners like Cameco in this situation but what that looks like looks different in every situation.”

Saskatchewan TB Control was unable to supply the number of people who have tested positive for the TB bacteria during the skin test and received treatment as a result of the case at the Cigar Lake mine.     

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