Tuberculosis Update
A recent issue of MMWR (Volume 58, #10;249-253) reviews trends in tuberculosis in the United States for 2008. Overall, the rate of TB infection in 2008 was the lowest since national reporting began in 1953. North Dakota reports the lowest TB rate (0.5 cases per 100,000 population), while Hawaii has the highest (9.6 cases per 100,000 population). In comparison, Missouri and Kansas have case rates of <2.0 and 2.0-4.0 per 100,000 population, respectively. Four states (California, Florida, New York, & Texas) accounted for approximately half the 2008 TB cases, & each of those states reported more than 500 cases. A total of 12,898 cases were reported.
Foreign-born persons account for a disproportionate number of U.S. TB cases. Persons from four countries (Mexico, the Philippines, India, & Vietnam) represent the majority of those cases. Racial/ethnic minorities are also encumbered with TB rates 8-23 times higher than whites, with Asians having the highest number of cases. TB rates declined among all groups in 2008.
Drug resistance continues to be of concern in TB. Multidrug-resistant TB (MDR TB) is defined as resistance to at least isoniazid and rifampin. The rate of MDR TB has remained stable, but is disproportionately higher among foreign-born persons (82% of MDR TB). Extensively drug-resistant TB (XDR TB) is defined as resistance to isoniazid, rifampin, fluoroquinolones, and at least one injectable drug (amikacin, capreomycin, or kanamycin). XDR TB has been reported in the U.S. since 1993, with four cases in 2008. The CDC recommends that TB prevention & control capacity should be increased, to ensure that TB rates continue to decline in the U.S.
