Yerevan, Armenia - In a barren hospital room, Arman lies on a messily made bed as a nurse administers one of two daily antibiotic injections into his forearm. The 35-year-old ex-soldier was admitted nearly 18-months ago, having suffered a relapse of the bacterial lung infection tuberculosis (TB).

At a university laboratory in Tanzania, an unusual kind of medical research is taking place. Men in white coats watch as rats scurry around glass cages, but these rodents are not test subjects in the latest drug trial. In fact, they're the ones doing the testing, and they're proving rather good at it.