Cases of tuberculosis that are resistant to most of the drugs used to treat the disease are on the rise around the world, posing a risk of reimportation to areas such as the United States that have controlled the disease, according to a new report.
The threat of tuberculosis "transcends borders," said Dr. Jack Chow, assistant director general of the World Health Organization, which co-authored the report. "It is not going to stop at passport control."
The report issued Tuesday, by the WHO, the Centers for Disease Control and Prevention and the Global Alliance for TB Drug Development, describes multidrug-resistant TB as a "global crisis."
"Multidrug-resistant TB" describes strains of the tuberculosis bacterium that have evolved to resist two of the four main drugs used to treat the disease. When TB strains develop resistance, treatment can take up to two years and cost up to $250,000.
Each year, the report said, there are approximately 8 million new cases of TB. Of those, more than 300,000 cases are multidrug resistant, and 79 percent of them are unaffected by three of the four main drugs.
Drug resistance is clustered in Eastern Europe, the former Soviet Union, India and China, according to the report --- locations where rates of HIV infection are rising. HIV's damage to the immune system makes it more likely that TB infection will turn into TB disease.
Tuberculosis has been controlled in the United States, according to the CDC. There were 15,075 U.S. cases in 2002, the last year for which complete numbers have been collected; cases have declined every year since 1992.
But the country remains at risk of TB importation, said Dr. Ken Castro of the CDC: The rate of drug-resistant TB among foreign-born U.S. residents is twice the rate among the native-born.
Travel back and forth from TB-endemic areas also brings the disease into the country, he said, citing the case of a California woman who recently called the CDC for advice because her son and daughter-in-law, who had been on long-term assignment overseas with the U.S. armed forces, were returning to the United States. During the deployment, her daughter-in-law had contracted multidrug-resistant TB.
TB remains a persistent problem in Georgia. In 2002, there were 533 cases of active TB in the state. Two were multidrug resistant; 33 were resistant to a single drug.
Georgia's rate of active TB was 6.2 cases per 100,000 members of the population --- higher than the 5.2-per-100,000 rate for the United States as a whole.
Fulton County's rate is 14.4 per 100,000, more than double the rate for the state as a whole and greater than that of many countries, including Canada, Cuba, Italy and Germany.
In Georgia, most TB cases occur among African-Americans, who make up 29 percent of the population but account for 60 percent of TB cases.
One-third of the cases in Georgia are among those born outside the United States. In 2002, 50 percent of refugees who arrived in Georgia had positive skin tests for TB.
Last month, Gwinnett County health officials uncovered two cases of active TB in siblings attending Lilburn Middle School and Rockbridge Elementary School. Two younger siblings not attending school also had active TB.
Almost 300 students, faculty and staff in the Gwinnett public schools were tested for TB exposure; 20 had positive skin tests, indicating they had become infected with the TB bacterium but had not developed the disease.
Health officials declined to say how the family became infected.