The case of a Nepalese man with extensively drug-resistant tuberculosis (XDR-TB) traveling through 13 countries before illegally entering the U.S. from Mexico, "first described by Betsy McKay at the Wall Street Journal, provides a window on a problem that health officials say is sure to arise more and more often," NPR's "Shots" blog reports. "'We estimate at any one time in the world there are about 630,000 cases of MDR-TB,' Dr. Dennis Falzon of the World Health Organization tells Shots, referring to multidrug-resistant TB," the blog writes. Of those, about 60,000 have XDR-TB, which is resistant to second-line drugs as well as first-line therapies, according to the blog. "The CDC has recorded 63 cases of XDR-TB from 1993 through 2011 (the most recent data available), more than half of them among foreign-born people," "Shots" writes (Knox, 3/8).