A yearlong outbreak of tuberculosis in the Kansas City, Kansas, area has taken local experts aback, even if it does not appear to be the largest outbreak of the disease in U.S. history as a state health official claimed last week.

“We would expect to see a handful of cases every year,” said Dr. Dana Hawkinson, an infectious disease doctor at the University of Kansas Health System. But the high case counts in this outbreak were a “stark warning,” he said.

The outbreak has killed two people since it started in January 2024, Kansas state health department spokeswoman Jill Bronaugh said. Health officials in Kansas say there is no threat to the general public.

TB is caused by bacteria that lives in the people’s lungs and spreads through the air when they talk, cough or sing. It is very infectious, but only spreads when a person has symptoms.

Once it infects a person, TB can take two forms. In “active” TB, the person has a long-standing cough and sometimes bloody phlegm, night sweats, fever, weight loss and swollen glands. In “latent” TB, the bacteria hibernates in lungs or elsewhere in the body. It does not cause symptoms and does not spread to others.

Roughly a quarter of the global population is estimated to have TB, but only about 5% to 10% of those develop symptoms.

As of Jan. 24, 67 people are being treated for active TB, most of them in Wyandotte County, Bronaugh said. Another 79 have latent TB.

The state’s provisional 2024 count shows 79 active TB cases and 213 latent cases in the two counties where the outbreak is happening, Wyandotte and Johnson. Not all of those are linked to the outbreak and Bronaugh did not respond to requests for clarification.

The situation is improving, though: “We are trending in the right direction right now,” Ashley Goss, deputy secretary at the Kansas Department of Health and Environment, told the state Senate’s Committee on Public Health and Welfare on Jan. 21.

Kansas health officials called the outbreak “the largest documented outbreak in U.S. history” since the U.S. Centers for Disease Control and Prevention began counting cases in the 1950s.

But a spokesperson for the CDC on Tuesday refuted that claim, noting at least two larger TB outbreaks in recent history. In one, the disease spread through Georgia homeless shelters. Public health workers identified more than 170 active TB cases and more than 400 latent cases from 2015 to 2017. And in 2021, a nationwide outbreak linked to contaminated tissue used in bone transplants sickened 113 patients.