U.S. TB Rate in 2008 at Record Low; Minority, Immigrant Populations Remain Disproportionately Affected, CDC Report Says
Tuberculosis rates in the U.S. reached a record low in 2008, but the disease still disproportionately affects minority and immigrant populations, according to a CDC report released Thursday in the agency's Morbidity and Mortality Weekly Report, Reuters reports.
According to CDC, the U.S. in 2008 recorded a TB rate of 4.2 cases per 100,000 people, which is a 3.8% decline from the 2007 rate. The agency said the 2008 rate was the lowest recorded since the start of national recording in 1953. However, it also added that the rates of decline have leveled off, noting that TB rates declined by an average of more than 7% each year between 1993 and 2000. CDC also reported that the U.S. recorded the lowest number of new TB diagnoses in 2008, with 12,898 new cases.
Robert Pratt of CDC's Division of TB Elimination in the report said that TB "continues to disproportionately affect racial/ethnic minorities and foreign-born persons." The report found that compared with whites, TB rates are 23 times higher among Asians, eight times higher among blacks and 7.5 times higher among Hispanics. The report also found that about 41% of new TB cases occurred among people born in the U.S.
According to CDC, more than 10% of HIV-positive people in the U.S. have contracted TB, likely because the virus weakens the immune system. The CDC report also found that multi-drug resistant TB accounted for slightly more than 1% of all U.S. TB cases in 2008. According to Reuters, the World Health Organization is expected to release new data on the global MDR-TB burden to mark World TB Day on March 24. According to the agency's latest data, about 5% of the nine million new TB cases diagnosed annually worldwide are drug-resistant (Fox, Reuters, 3/19).
The CDC report is available online. Additional TB-related articles in the latest version of MMWR also are available online.
Although tuberculosis rates have declined in the U.S., drug-resistant strains of the infection among immigrants in California are becoming increasingly prevalent, the AP/San Jose Mercury News reports. California and other states with large immigrant populations are particularly vulnerable to drug-resistant TB because many people frequently travel to countries with higher TB prevalences -- such as China, India or Mexico -- or were born in such countries, according to the AP/Mercury News.
There were 2,696 recorded TB cases in California in 2008 -- the highest rate in the nation -- and the state also had 451 cases of drug-resistant TB identified between 1993 and 2007. About 83% of the drug-resistant cases involved foreign-born immigrants.
In addition, a statewide analysis of drug-resistant TB cases between 1993 and 2006 found that the proportion of TB patients who could develop extensively drug-resistant TB increased from 7% to 33%. "It's a wake-up call," Ritu Banerjee, a researcher with the University of California-San Francisco Division of Infectious Diseases department and lead author of the analysis, which was published in the journal Clinical Infectious Diseases in 2008, said.
The cost of treating a patient with XDR-TB can be as much as $1 million, with no guarantee of survival, Kenneth Castro, director of CDC's Division of Tuberculosis Elimination, said. "You get a couple of these patients and you can bankrupt a city program," he added.
The increase in drug-resistant TB comes as funding for TB programs is reduced, the AP/Mercury News reports. Jennifer Grinsdale, program manager and epidemiologist with the TB control section of the San Francisco Department of Public Health, said recent budget cuts have hindered the city's ability to administer TB tests and treat the infection. "Anywhere from two to 10 years from now, we'll see the impact for this," Grinsdale said (Barbassa, AP/San Jose Mercury News, 3/22).