According to the World Health Organization, the drug-resistant strain of tuberculosis (XDR-TB) is “a grave public threat.” It killed 52 HIV-positive South Africans last year, was found in 40 South African hospitals, and is now presenting a serious threat to positive people in 28 countries including China, India and Russia. Researchers are hoping to develop rapid tests to detect the disease and hospitals are using infection control methods such as ultraviolet lights to kill microbes and prevent unnecessary contact between people.