State health officials say cases of tuberculosis among immigrants are rising, raising concerns that North Carolina is headed toward a resurgence of the disease among its growing international population.

Tuberculosis, a bacterial disease that attacks the lungs and other organs, has been well-contained for years, with the number of cases plummeting since 1980. And overall, it is still on the wane.

But the foreign-born now make up more than 40 percent of the state's cases, and the numbers are rising as the foreign population grows. In 2000, 26 percent of the state's cases were among the foreign-born, and in 1983 it was less than 3 percent.

"If we continue on this trend, it's going to be a big problem," said Maureen O'Rourke, tuberculosis program manager at the N.C. Division of Health.

The problem is a national one. In a study released in July, researchers with the Centers for Disease Control and Prevention said the nation's health system is failing to adequately control TB in immigrants.

Nationally, from 1993 to 2006, cases among immigrants rose 5 percent as they dropped by 66 percent in the rest of the population. Fifty-seven percent of the nation's TB cases were among the foreign-born in 2006.

The study recommended increased screening of immigrants for the disease and suggested that the United States invest in programs to control TB around the globe.

TB is endemic in many places that send immigrants and refugees to North Carolina, including parts of Latin America, Asia and Africa.

In Mexico and other Latin American countries, public health officials estimate that at least 20 percent of people have been exposed to the disease. Those who have been exposed have no symptoms and are not contagious, but about 10 percent of them will eventually develop active TB.

TB exposure does not prohibit a person from entering the United States legally, and most are not even screened for it. Active TB would prevent a person from coming, but the study said that about 30 percent of foreigners in the United States are never tested for it -- including students, workers, visitors and those who enter the country illegally.

Even those with active TB usually are not a threat to the health of non-immigrants, said Dr. Jeff Engel, state epidemiologist, noting that TB cases among non-immigrants are falling.

He said the disease is not easily spread and is passed mostly among those who live together. Those who get the disease are usually cured with antibiotics. Drugs can also prevent those who have been exposed from developing the contagious disease.

Public officials say increased screening of immigrants could halt the spread, but they say they don't have the resources to begin testing and treating thousands of new patients. By state law, patients pay nothing for their treatment.

35 of 54 foreign-born

Gibbie Harris, the Wake County health director, said foreign-born residents accounted for 35 of the county's 54 TB cases in 2007. Just last year, Wake's clinic treated people from India, Mexico, Vietnam, Kenya, Morocco, China, Indonesia, Afghanistan and a handful of other countries.

Harris said widespread testing of immigrants for TB exposure would probably uncover many people at risk for the disease. Each positive test would mean ordering further medical tests, developing a treatment plan, buying the drugs and deploying a nurse to administer them. Public health workers must watch most patients take each dose of their treatment, which sometimes entails several pills a week for months.

"It takes a lot more than just doing the test," Harris said.

Engel said he would like to begin a new TB campaign in North Carolina, targeting immigrants with testing programs and educational materials. But he said that effort would require more money from the federal government, which funds most infectious-disease programs.

"I think it's a major concern," Engel said. "A national concern."