Wednesday, May 30, 2007

Resistant TB leaves few options

The highly dangerous form of tuberculosis that has infected a man now in quarantine resists almost all drugs used to treat TB, leaving only less effective options.
It's called "extensively drug-resistant tuberculosis," or XDR TB. It can't be cured by the two best first-line drugs, isoniazid and rifampin, or the best second-line medications.
That leaves options that are much less effective, according to the federal Centers for Disease Control and Prevention. Some programs have achieved cure rates for an estimated 30 percent of affected people, CDC says.
Success depends heavily on how resistant the germ is, how severe the disease is, and whether the patient's immune system is weakened, CDC says.
This form of TB is rare. Only 49 cases were reported in the United States between 1993 and 2006; 17 have been diagnosed since 2000. By contrast, the nation reported 13,767 ordinary TB cases last year alone, an all-time low.
The extremely resistant form can be caught from other people or develop from an ordinary case of TB. It generally appears in people who don't take their medicines regularly or don't take all of them; or those who develop active TB after having taken tuberculosis drugs in the past; or who are exposed to the germ from other people.
This dangerous form spreads the same way as ordinary TB. — when someone breathes in the germs from the air. TB germs can enter the air when an infected person coughs, sneezes, or even speaks. The germs can float for hours. TB is not spread by a handshake, sharing a glass or by kissing, the CDC says.

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