Giant rats may strike fear and disgust into the hearts of homeowners worldwide, but researchers in impoverished Mozambique are turning some of them into heroes.

At Eduardo Mondlane University in Maputo, nine giant rats are busy at work sniffing out tuberculosis-causing bacteria from rows of saliva samples.

These are no ordinary rats, as they have undergone six months of training in Tanzania. Their most distinguishing asset is their impeccable sense of smell.