Tuberculosis continued its slow slide toward elimination in the United States last year, but with most cases now likely brought into the country from abroad, ridding this country of the infection depends on progress against it elsewhere, the Centers for Disease Control and Prevention reported Thursday.

There were just 9,412 new cases of active tuberculosis in 2014, a 2.2 percentage point decline from the previous year, the CDC reported in its weekly Morbidity and Mortality Weekly Report. Of those, more than half appeared in Asians and Hispanics, the vast majority of whom were born abroad, according to the study and Philip LoBue, director of the CDC's Division of Tuberculosis Elimination.

In fact, the tuberculosis rate among Asians (17.9 per 100,000) is 29 times higher than it is among whites (0.6 per 100,000), the new report shows. More than half the new cases were clustered in four states — California, Texas, New York and Florida, which have one third of the U.S. population.

"It's a matter of them likely to have been exposed because they come from countries where tuberculosis is much more common," LoBue said in an interview. China, India, Mexico, the Philippines and Vietnam are responsible for more than half of the foreign born tuberculosis patients in the United States, the report shows.

Though the numbers have been declining globally, there were 9 million new tuberculosis cases and nearly 1.5 million fatalities in 2013, according to the World Health Organization.

Tuberculosis is a potentially serious bacterial disease that primarily affects the lungs. The active form is contagious, but not highly so. The latent version does not cause health problems and is not contagious. According to the CDC's last estimate, which is 15 years old, 11 million Americans are believed to have latent TB.

Tuberculosis is treatable with antibiotics, but the course can be long and complicated. Another problem slowing the halt of the disease is development of multi-drug resistant and extensively drug resistant strains of the infection. While there were only about 100 such cases in the Unites States, and most were among foreign-born patients, the prevalence is much greater in some other countries that lack the public health capacity to ensure that people consistently take their medication, LoBue said.

"If your goal is elimination," he said, "there's going to need to be a much greater rate of decline. That's true in the United States as well."