Tuberculosis rates in the United States dropped more than 10 percent last year compared with 2008, the sharpest decrease ever recorded in a single year, the Centers for Disease Control and Prevention reported March 31.
The 2009 rate was 3.8 cases per 100,000 people, down from 4.2 the year before, according to results from the National TB Surveillance System reported in the March 19 issue of the centers’ Morbidity and Mortality Weekly Report. Declines were reported among people born both in the United States and abroad.
The reasons for the decline were not entirely clear, The New York Times reported. Federal health officials did not rule out the possibility that some cases went uncounted or perhaps even undiagnosed because patients did not have access to medical care.
Carla Winston, a senior epidemiologist with the CDC and the report’s lead author, said public health efforts to identify TB outbreaks earlier and interrupt transmission in hard-hit communities might have contributed to the decline, along with demographic shifts and more aggressive screening of would-be immigrants.
But the case counts still need to be verified, she said, adding, “Many factors can affect TB case counts by the states, including possible underreporting.”