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TB terror

Governments must come up with funds to squelch drug-resistant strains of the disease before it turns into a global scourge.

June 10, 2007

THE PASSENGERS who shared two transatlantic airplane flights with Andrew Speaker, the tuberculosis-infected honeymooner, may get lucky. Officials now believe the jet-hopping Atlanta lawyer with "extensively drug resistant" TB, or XDR TB, is less infectious than feared. Still, if any of those passengers are HIV-positive or undergoing chemotherapy, the wait to learn whether they have caught Speaker's TB will be agonizing. For the immune-compromised, XDR TB is nearly always fatal.

If it turns out that no one has been infected through Speaker's irresponsibility, public health officials should write him a thank-you note. He has spotlighted for the entire world the extreme dangers of drug-resistant TB -- a feat scientists have been unable to achieve in 15 years of increasingly dire warnings and chronic under-funding of TB research and control.

Most of us are not yet scared enough, however. Consider the potential of a disease that's as deadly as AIDS but can be transmitted by a single cough; that once killed one in five adults; that now infects 2 billion people worldwide and kills 1.6 million a year; that quickly becomes impervious to antibiotics when the drugs are improperly used; and that can incubate in and be spread by asymptomatic patients like Speaker.

In the 1970s, eradicating TB appeared possible. Now, the drug-resistant strains are winning. Of the 9 million new TB cases each year, an estimated 450,000 are multi-drug resistant, or MDR. Only two-thirds of MDR TB patients are cured. The World Health Organization estimates that in 2005, there were 27,000 cases in 37 countries of XDR TB, which is resistant to at least three of the six second-line drugs used when the first drugs fail. The cure rate for XDR TB patients is just one-third. Scariest of all, two women in Italy recently died from a fully resistant type of TB that's officially incurable. (Scientists are dubbing it XXDR TB.) Today, TB terrorizes those whose immunity has been weakened by HIV, hunger, alcoholism or other diseases. If the new strains become dominant, everyone is at risk.

XDR TB is already too widespread to quarantine. We need to combat it -- globally -- before it becomes pandemic. Last week, the WHO asked governments worldwide to pay up the $3 billion a year needed to fund existing TB programs -- and an additional $1 billion a year to combat XDR TB. In the U.S., Sen. Sherrod Brown (D-Ohio) and others proposed spending $300 million on TB next year, much of it on research. Given that isolating and treating a single XDR patient can cost up to $250,000, the case for spending far more on prevention and control is self-evident.

Other necessary measures include:

* A better TB test. Standard TB tests are 100 years old and generate false results 30% of the time. Most people infected with drug-resistant TB don't know it because their countries don't test for it. It can take up to four months to culture and diagnose MDR TB, and up to six months to diagnose XDR TB. By then, many patients are dead and countless others infected. The TB genome has been sequenced, and development of a 24-hour biomarker test for the new strains has become possible. It must be funded now.

* New TB drugs. The latest is 40 years old. We need treatments that take weeks, not the current two to three years. Developing a vaccine will be difficult, but it must be a priority.

* Enforced travel bans. As two congressional committees learned last week, airlines and border officials need timely lists of infectious people, and these people must not be allowed to travel.

* HEPA filters. At least 75% of U.S. aircraft have these high-efficiency air filters that screen out bacteria and viruses; many old planes around the world don't. Public health experts think they should, to reduce the risk not just of TB but of all infectious diseases. The WHO has tracked airplane outbreaks of influenza, measles, SARS and meningitis. The U.S. should phase in a requirement for all planes landing on its soil to have HEPA filters -- and lobby for similar international standards.

The Speaker case teaches us not to breathe easy. One day, a plane landing at LAX could carry a passenger infected with XXDR TB, a bioterror agent, Ebola or an emerging virus. Will we be ready?

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