Tuberculosis strain hits St. Croix County
St. Croix County Public Health treated several cases of latent Tuberculosis this year, after an infected Minnesotan made contact with several people through work.
Public Health Coordinator Deb Lindemann said at the Nov. 14 St. Croix County Health and Human Services Board meeting they tested 92 possible contacts for tuberculosis.
Three of those tested positive for latent tuberculosis, and were treated so that it did not become active in the patients.
"We wanted to stop it right where it was," Lindemann said.
Patients with latent tuberculosis will not show symptoms, but it could turn active later in life.
Over the past decade, St. Croix County has had between zero and one active case per year.
There were five latent cases treated in 2015, and 16 in 2015. Before the testing this year, there were five latent cases.
Lindemann said it took 322 staff hours to test and treat for the infection and $5,700. The cost to treat one active case is $55,000, she said.
The cases were not drug resistant.
Kristine Lees, supervisor of the disease prevention control team in Dakota County. Minn., said strains are occasionally resistant to one possible treatment, though that's rare, and multi-drug resistance is even more rare.
Compared to the measles outbreak earlier this year, epidemiologist Kris Keller of Washington County, Minn., said tuberculosis outbreaks are more likely to stay contained.
Tuberculosis has a different exposure time, level of infectiousness and does not stay airborne as long as diseases such as measles.
Many of the cases they currently are treating were likely latent for a long time before patients began showing symptoms.
When active cases show up, patients go through at least six months of directly observed treatment. The average time is nine months.
Public health nurse Julie Winner said latent cases often become active when the patient is older, and immunity is lowered or have contracted another disease.
Drug resistance can be triggered by incomplete treatment, which is why public health nurses visit a patient every day on average for about nine months, to provide directly observed treatment (DOT).
"The goal is to make sure that somebody does get the right medication for the whole treatment to prevent the bacteria to become fully resistant," Lees said. "That's part of the reason we do DOT, to make sure resistance (doesn't occur)."
Jill Timm, supervisor of disease prevention and control for Washington County, said many of the patients' cases — both countywide and statewide — originated when they were living in foreign countries, or contracted the infection by having connections to other countries.
"I think the risk will always be there for a couple cases a year, so long a TB still is common in other parts of the world," Lees said. "There's a lot of travel, so there's always that risk."