The U.S. tuberculosis rate hit an all-time low in 2008, but the infection continues to disproportionately affect minorities and immigrants, the U.S. Centers for Disease Control and Prevention reported on Thursday.

The CDC said 12,898 new cases were reported in 2008, also a new low, with 41 percent of those cases among people born in the United States.

“The TB rate declined 3.8 percent from 2007 to 4.2 cases per 100,000 population, the lowest rate recorded since national reporting began in 1953,” the CDC team wrote in the organization’s weekly report on death and disease.

“In 2008, the number of TB cases and annual TB rate reached all-time lows in the United States.”

It said the rate of decline had plateaued. Between 1993 and 2000 the rate of TB cases fell by more than 7 percent on average each year.

“TB continues to disproportionately affect racial/ethnic minorities and foreign-born persons,” the CDC team, led by Robert Pratt of the Division of TB Elimination, wrote in the report.

TB rates were 23 times higher among Asians, eight times higher among blacks, and 7.5 times higher among Hispanics than among whites, the CDC said.

More than 10 percent of people who have tested positive for the AIDS virus had TB; the immune suppression caused by HIV can make a person far more susceptible to TB. The AIDS epidemic drove up the number of cases in the United States in the 1990s and is still doing so globally.

Multi-drug resistant TB accounted for just over 1 percent of all U.S. cases, the report found.

Globally, MDR TB is a much bigger problem and the World Health Organization is expected to release new figures on World Tuberculosis Day next Tuesday. The latest statistics had suggested that 5 percent of the 9 million new cases of TB diagnosed globally every year are drug resistant.

Nearly a third of the world’s population is infected with the bacterium that causes tuberculosis, although active TB only develops in a fraction of those cases. Antibiotics can cure it although 1.7 million people die every year from TB.

WASHINGTON (Reuters)