Process illustrates collision between public health, politics.

Few diseases need new medicines as much as tuberculosis, with most patients diagnosed by a method more than a century old and treated with drugs more than 40 years old. Yet global investment in new tools declined last year, a new report found.

NASHVILLE, Tenn.—Natalie Skipper started feeling under the weather a few weeks after returning home from volunteering at a South Africa hospital. "The worst flu I had ever had in my life," she said.