Tuberculosis (TB) rates in the United States were at an all-time low in 2006, though progress to eliminate TB continued to slow and drug-resistant TB presented challenges, according to two articles in the March 22 issue of Morbidity and Mortality Weekly Report.
In 2006, 13,767 TB cases were reported in the United States, down from 14,085 cases in 2005. The 2006 national TB case rate—4.6 cases per 100,000 people—was the lowest since reporting began in 1953. However, the decline of 3.2 percent from 2005 to 2006 was one of the smallest in more than a decade. The average annual decline in the national TB rate slowed from 7.3 percent per year in the 1993 to 2000 period to 3.8 percent per year in the 2000 to 2006 period.
Multidrug-resistant TB is resistant to at least two first-line drugs, and extensively drug-resistant TB (XDR TB) is resistant to the same two first-line drugs, as well as to any fluoroquinolone drugs and at least one second-line injectable drug. Patients with XDR TB, particularly those who live in areas with less access to the full range of effective drugs, are virtually untreatable using the available drugs. A Centers for Disease Control and Prevention (CDC) analysis, which included provisional data for 2006, found that between 1993 and 2006, 49 XDR TB cases in the United States were reported to the CDC.
XDR TB continues to be widely distributed geographically in the United States and abroad, causing public health concern. The risk of XDR TB appears to be low in the United States. However, owing to the ease with which TB can spread, XDR TB will continue to pose a serious risk to the United States as long as it exists anywhere else in the world.
"CDC and its domestic and international partners are taking many steps to prevent further spread of drug-resistant TB and to reduce the overall burden of the disease," said Dr. Ken Castro, director of CDC’s Division of Tuberculosis Elimination. "These efforts include developing new treatment regimens, increasing the capacity of health professionals to provide effective treatment, and issuing new recommendations for improved screening and treatment for U.S. immigrants."
