Feb. 1, 2008 -- CDC researchers today reported that despite a drop in tuberculosis cases, the U.S. probably won't meet its 2010 tuberculosis reduction goal.
Tuberculosis (TB) is an infectious disease caused by a bacterium that spreads through the air, usually through coughing.
Tuberculosis cases are becoming rarer in the U.S., but it isn't happening fast enough to meet the federal government's goals, Diane Bennett, MD, MPH, and colleagues say.
Bennett's team reports that in the U.S., there were 4.6 tuberclulosis cases per 100,000 people in 2005, down from 10.5 cases per 100,000 people in 1992. The government wants to whittle down that number to less than one case per 1,000,000 people.
Drop in Tuberculosis Cases
The U.S. tuberculosis rate has been dropping by 2% to nearly 9% yearly for a decade. But "even a 20% annual rate of decline between 2006 and 2010 would not allow the target to be reached in 2010," write Bennett and colleagues.
They took a closer look at latent TB infection, in which people aren't sick (but may become sick in the future) and can't spread tuberculosis to other people.
In 1999-2000, more than 11 million people in the U.S. -- 4.2% -- had latent TB, based on tuberculosis skin tests taken by more than 7,300 people in a national health survey.
Among adults aged 25-74, latent TB cases dropped from 14.3% to 5.7% between 1971-1972 and 1999-2000, the study shows.
Latent TB cases are more common (but still rare) among men, people born outside the U.S., people living in poverty, Mexican-Americans, and African-Americans, according to the 1999-2000 tuberculosis statistics.
The report appears in the American Journal of Respiratory and Critical Care Medicine.
To put tuberculosis in perspective, consider these facts from the CDC and the World Health Organization (WHO):
- One-third of the world's population is infected with tuberculosis.
- Each year, nearly 9 million people worldwide become sick with tuberculosis.
- Among people who are infected with TB (but not also with HIV, the virus that causes AIDS), 5% to 10% become sick or infectious at some time during their life.
- Left untreated, each person with active tuberculosis disease (not latent TBÂ infection) will infect 10-15 people, on average, every year.