SAN FRANCISCO – The worst forms of the killer tuberculosis bug have been gaining ground in the United States, alarming public health officials over imported drug-resistant strains of a disease that is mostly under control in this country.
Although the number of drug-resistant TB cases in the U.S. is small compared to developing nations, health officials here warn that visitors from other countries who are unaware of their infections are bringing over the deadliest mutations.
Often those with drug-resistant strains stop taking their medicine when they feel better but aren't cured.
That's what happened with Pich Chhieng, 61, a teacher who was infected in his native Cambodia and carried it with him to this country. He took medication for eight months but abruptly stopped because he ran out of money and was feeling much better.
He didn't know until he was hospitalized while visiting family in Los Angeles that by neglecting his treatment he had allowed the disease to mutate, and the drug-resistant bacteria had overwhelmed his lungs.
"I knew it wasn't cured yet, but I thought it wasn't that strong," said Chhieng, who has been forced to stay in California until he is cured. "I thought it was gone, and when it came back like that, I felt really bad. I wanted to kill myself."
The majority of drug-resistant infections in the U.S. are brought in by legal visitors, and health officials argue that simply tightening immigration controls won't solve the problem.
The only visitors to the U.S. who are screened for tuberculosis and other medical conditions are immigrant and refugee visa applicants, and TB experts say there is no easy way to screen the millions of tourists, workers and others who aren't currently evaluated.
Worldwide, TB kills 2 million people each year, mostly in Africa and southeast Asia.
Of gravest concern is so-called "extensively drug-resistant" TB, which recently killed more than 50 people in South Africa. It's been found in limited numbers in the U.S. — 74 reported cases since 1993.
The strain is nearly impossible to cure because it's immune to the best first- and second-line TB drugs. It is as easily transmitted through the air as garden variety TB.
Health officials here also have been jolted by a spike in a milder but still-lethal form called "multi-drug resistant" TB.
That's the strain afflicting Chhieng. It responds to more treatments but can cost up to $250,000 and take two years to cure.
The number of cases of that variety are multiplying worldwide, jumping more than 50 percent from about 273,000 in 2000 to 425,000 in 2004, according to a study published in August in the Journal of Infectious Diseases.
In the U.S., 128 people were diagnosed with it in 2004, a 13 percent spike from the previous year.
Health officials say a drug-resistant outbreak like the one in South Africa is unlikely here because of stringent public health safeguards, but warned that more widespread infections are possible in the future because the disease is so easily transported.
"That's a red light flashing," said Dr. Charles Wallace, an infectious disease specialist with the Texas Department of State Health Services. "That's a warning sign that TB is becoming more difficult to manage when it goes untreated and undiagnosed. We always like to think that it can't happen here, but any disease that travels through the air could be on a plane flying here at any time."
U.S. health officials believe more money is needed for prevention and treatment abroad.
"It certainly has outbreak potential if we don't get on it right away," said Dr. Kenneth Castro, director of the CDC's Division of Tuberculosis Elimination.
The states with the highest numbers of multi-drug resistant cases in the last decade were New York, California, Texas and Florida, according to the CDC.
In New York City, a series of deadly HIV-related drug-resistant TB outbreaks ripped through prisons and hospitals in the early 1990s, killing hundreds of people, including many who had started treatment.
But mortality rates dropped dramatically after the health department created a separate unit to target the strain, stepped up education in multiple languages and improved coordination with doctors.
Last year, overall tuberculosis rates in the city hit their lowest point since the peak of the most recent epidemic in 1992; however, drug-resistant cases jumped from 18 in 2004 to 24 cases last year.
"The threat is always there," said Dr. Sonal Munsiff, director of the city's tuberculosis control bureau. "And I think it's increasing in some ways because drug-resistant tuberculosis is increasing worldwide. So it doesn't take long to get a case here."
Health officials complain that federal funding has not kept up with the increased demands of battling the disease. State and county health departments wind up paying for uninsured patients like Chhieng, who has six months left in his two-year treatment.
Chhieng praises the treatment he has received in the U.S. He says he has gained weight and is feeling better, but has not seen his wife in a year and a half. And he regrets being a burden to his daughter-in-law, who is housing him and translates for him.
"Everything's better right now," he said. "I'm going to have a long life to live. I really miss home. I miss my wife, I miss my country, I miss the weather over there. I just want to go home."