According to the Centers for Disease Control and Prevention (CDC) in the U.S., drug-resistant strains of tuberculosis (TB) are on the rise and present the threat of a pandemic.
The CDC says that cases of tuberculosis that were resistant to the two drugs considered the first-line of treatment rose 13 percent to 128 in the United States between 2003 and 2004, the highest yearly increase since 1993.
It appears the majority of the cases were in people born outside the United States, in countries such as Mexico and Vietnam.
Health experts estimate that as many as 9 million people worldwide become sick from TB and 2 million die each year from the bacterial disease that usually affects the lungs.
It is estimated that one-third of the world's population, are infected with the tuberculosis bacillus, and 5 to 10 percent of those infected will become sick or infectious in their lifetime.
TB is the biggest killer of people with HIV, and accounts for 13 percent of AIDS deaths.
The CDC says that of more than 17,000 TB cases reported on six continents between 2000 and 2004, 20 percent were resistant to the two first-line drugs.
Of that number 2 percent were in the category of "extensively drug-resistant" TB, designating cases that were non-responsive to three or more classes of second-line drugs in addition to the most common medications.
Health experts are concerned of the future risk of an epidemic of uncontrollable TB and are calling for increased funding for laboratories and programs to detect and fight the disease.
The figures were released by the CDC ahead of World TB Day and Kenneth Castro, director of the TB elimination program at the CDC says the emergence of multi-drug-resistant tuberculosis in the United States more than 15 years ago served as a harbinger of a pandemic.
Castro says the ability of the disease to travel easily across borders makes worldwide TB control efforts critical.
Castro said drug-resistant TB was widely distributed geographically and is difficult to treat since it requires medicines that are costlier but less effective.
While the most-resistant TB was identified in all regions, it is apparently most common in Eastern Europe and western Asia.