No one knows the exact number of cases of the two types of drug-resistant TB, called MDR and XDR for multidrug-resistant and extensively drug-resistant.
A few places, like Peru and Hong Kong, have fought the disease effectively, as New York City did in the early 1990s. Progress has been made in parts of Siberia, but in another region of Russia, more than a quarter of all cases are drug-resistant. And in Africa, a vast majority of cases have probably not even been diagnosed, the report said.
