Researchers look for new TB drugs

WASHINGTON -- Tuberculosis is the No. 1 killer of women of childbearing age worldwide, and the epidemic is growing with the spread of bacteria that is resistant to drugs that have worked in the past.

Experts attending the 4th World Congress on Tuberculosis said Monday that latent TB is a difficult disease to diagnose. In poor countries, women with the disease often aren't diagnosed until severe symptoms appear, they said.

"Many women are diagnosed only after they have become too ill" to care for their families, said Carol Nacy, head of the Sequella Foundation, a private group that is organizing tests for new TB drugs and vaccines.

By the time the disease is diagnosed, a patient may have infected 10 to 15 others, Nacy said. Even when women are diagnosed and receive drugs to treat their TB, mothers will often give the medicine to their children instead of taking it themselves.

"That's one reason TB is the number one killer of women of childbearing age," Nacy said Monday at a news conference of the World Congress.

Historically, tuberculosis is one of most deadly diseases known. About a third of the human population, roughly two billion people, are infected with TB bacteria, often in a latent form difficult to diagnose. But even in that form, the disease can be spread as droplets from sneezing or coughing.

About 10 percent of those with a latent infection, some 200 million people, will develop an active disease. About two million people worldwide die of TB annually, and some estimate that more than 90 million people could succumb to the disease over the next 30 years.

TB is a significant public health problem in developing nations, with China and India accounting for about a third of all cases worldwide. There were fewer than 16,000 cases of active TB in the United States last year, and about half of those cases involved recent immigrants.

A combination of drugs, including isoniazid and rifampin, has been shown to cure TB, but the treatment requires the medications be taken every day for 6 to 9 months, a regimen that is often difficult for patients to follow.