Exploding World 'Godzilla' TB
Epidemic Could Reach US Soon
By Andrew Wong
Tuberculosis remains the most deadly infectious disease in China accounting for more than 250,000 deaths each year
Tuberculosis, the Godzilla of bacterial diseases, infects up to a third of the world's population and currently kills more people per year than any other single infectious agent.
Ninety-five percent of TB cases occur in developing countries, so it's easy for Americans to ignore this affliction. But we may no longer be able to afford to do so, health experts warned at a press conference sponsored by the World Health Organization in connection with its annual World TB Day on Wednesday.
The reason? Deadly drug-resistant TB strains are springing up around the world.
"In today's global society, increasing drug resistance [to tuberculosis] anywhere becomes a threat everywhere," Dr. Ken Castro, director of the Centers for Disease Control's TB Elimination Division, said at the briefing. "Tuberculosis has the power to adapt, to grow stronger, and to travel as easily as we do from one nation to another."
Just last October, a Ukrainian emigre traveling on a Paris-New York flight may have infected a number of passengers with a strain of multi-drug resistant TB.
Luckily, the man visited a Pennsylvania health clinic two days later, and state health investigators immediately called the airline and contacted the passengers who had sat near him.
Thirteen of the passengers tested positive for TB, and were treated immediately with preventative medication (although it's not clear that the man actually infected the passengers: some may have already had the bug).
This case is the latest in a small but growing number of incidents where travelers have spread active TB on airplanes.
From 1992 to 1994, the CDC reported seven such cases, including two that involved multi-drug-resistant tuberculosis. These seven people, including six passengers and one flight attendant, potentially exposed more than 2,600 passengers on a total of 191 flights to TB, according to a recent WHO report, Tuberculosis and Air Travel: Guidelines for Prevention and Control.
Most of the exposed passengers were tracked down by the airline, tested, and treated. In many cases, the people who tested positive may have already been infected with TB, and no person has actually developed active TB symptoms from an airline flight, the WHO report said.
However, as air travel increases, and the number of drug-resistant TB cases careens out of control in Russia and other nations, the likelihood that planes will become incubators for dangerous TB infections is increasing, the report warned.
"While screening for TB is usually mandatory for immigrants and refugees, the overwhelming majority of passengers flying on commercial aircraft" are not screened for TB, according to the Tuberculosis and Air Travel Report.
In 1994 alone, "there were almost 97 million passengers on international flights between the U.S. and the rest of the world, the report said. "Clearly, medical examination of millions of people traveling by air worldwide would not be possible."
Tuberculosis accounts for more than 250,000 deaths each year in China.
If new strains of TB are spread to the U.S., they could prove highly expensive to treat. Ordinary TB can be effectively treated with a six to eight month course of four very cheap medications. But the medications which work against drug-resistant TB can cost up to $10,000 per patient. In the late 1980s and early 1990s, the U.S. spent over $1 billion to treat a mini-epidemic which involved less than 2,000 cases of multi-drug resistant tuberculosis, Castro said.
Do refugees and immigrants pose a health danger?
The U.S. requires both refugees and immigrants to be medically screened for TB and a host of other infectious diseases within a year before leaving their home country, and also provides free medical screening and treatment to refugees within 90 days of their arrival in the U.S., according to Dr. David Smith of the U.S. Government Office of International and Refugee Health.
Under these requirements, a person can theoretically become infected with TB within a year before entering the U.S., then become infectious once he or she has entered the country.
One indication that current TB screening procedures may not be working: 42 percent of documented TB cases in the U.S. last year occurred in foreign-born residents, said Castro, up from about 22 percent in the mid-1980s.
The CDC is "concerned" about the possibility that current regulations are inadequate to stem the flow of infectious, multi-drug resistant TB into the U.S., said Dr. Robert Wainwright, director of the agency's Division of Quarantine. "We are now working with the INS to look at the possibility of decreasing [the] times" in which a person has to have a medical exam before entering the country.
But requiring medical exams closer to the time of emigration is not necessarily the solution, Wainwright said. "Somebody could be infected with TB and not about to transmit the disease at the time of the medical exam, and theoretically, within a few days or weeks, could convert to being infectious."
Another strategy for addressing the problem is to spend more U.S. government money to combat the global TB epidemic, health advocates at the WHO briefing recommended.
"What we choose to do globally will benefit us," Dr. Castro said. "If we sit back and allow drug-resistant tuberculosis to grow unchecked, we may one day be faced with the threat of incurable TB in our own midst."