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How Can TB Impact Me?

When most people think of tuberculosis (TB), we think of it as a far-removed disease, affecting people from the distant past or from far-off shores. But TB maintains a global presence, even in Seattle, the home of the Center for Infectious Disease Research.

“We have about two new active TB cases every week,” said Dr. Masa Narita, director of the King County TB Control Program. This corresponds to about 100 people falling sick with TB in King County each year (PDF).

Understanding the Risks of Infection

As a nexus for international trade and travel, King County has TB disease rates that are one and a half times higher than the national average (about three cases per 100,000 people, which translates to 10,000 people sick per year). About 80% of patients are born in countries where TB is still widespread, although the rates of TB disease in foreign-born people are declining.

“Age is also a risk factor,” said Narita. “You have people who have lived their entire lives in America who were infected when TB was still endemic here during the 1940s and 50s, who are only now getting sick.” This is due to the ability of TB to remain latent in a person’s body for a long time, then – for reasons we’re still trying to understand – become active and make people sick.

“There’s a lot of stigma tied to this disease,” said Pecha. The majority of people who get sick come from vulnerable, marginalized, and underrepresented populations, including the homeless1. “We have to be sensitive working with patients and their needs,” said Narita.

The majority of patients with active TB disease get referred from primary care providers, but because the initial symptoms (coughing, fever, fatigue, chills, night sweats, loss of appetite) are common to many diseases, misdiagnosis is common. “It often takes multiple visits to the doctor before they are referred to us,” said Narita. This long lag time between the onset of active disease, diagnosis, and the start of treatment increases the chances that the TB infection will spread to other people.

“Models suggest that there are 100,000 people infected in the King County area,” said Monica Pecha, lead epidemiologist with the TB Control Program. The vast majority of these people are latently infected and will not get sick from the infection.

“We’d like to be able to screen and treat everyone, but we don’t have the resources to do that,” Pecha said. Because people who are recently infected are more likely to become sick with the active disease, the team focuses on finding potential “direct contact cases,” who are people who get infected from a known patient with active TB disease.

Activating the Response Team

For each active TB case, the TB Control Program assembles a team of highly trained disease intervention specialists. “We try to match our team based on the specific needs of each patient.” said Pecha.

In addition to a nurse who provides treatment, the team may also include an outreach worker and social worker to help meet other necessities. This group works over the course of several months toward important goals:

  1. Make sure that the patient receives and takes the treatment that they need (which involves taking multiple drugs for at least six months).
  2. Work with the patient to determine who they have been in recent contact with.
  3. Track down and test these potential contact cases to contain the infection spread.

“We first check immediate household members,” said Pecha. “If there is evidence of transmission, we widen our search.” Co-workers who share an office space, classmates, and others with prolonged contact with the patient while in enclosed spaces are also screened. During a recent investigation, the TB Control Program team tested over 200 students and staff at a local high school suspected of direct contact, working with volunteers in addition to their disease intervention team.

“Because of our limited resources and staffing, we have to operate reactively with containment as a goal,” said Narita. This necessitates sustained government funding of Public Health programs to enable their continuing surveillance. Previous cuts in Public Health budgets were accompanied by increases in the number of TB cases.

To turn the tide, Narita is optimistic that efforts by CIDR as well as other research centers will result in new diagnostics that can better predict people who will become actively sick with TB and drugs that can cure the disease in a shorter time with fewer side effects. “With better diagnostics and treatments, we would be able to take a more proactive role with elimination [of TB disease] as our goal,” he said.

More Information


Many thanks to Masa Narita and Monica Pecha for their time during the interview Dec 16, 2016, and for their subsequent help pulling together resources.