Giant rats may strike fear and disgust into the hearts of homeowners worldwide, but researchers in impoverished Mozambique are improbably turning some of them into heroes.
At Eduardo Mondlane University in the capital Maputo, nine giant rats are busy at work sniffing out tuberculosis-causing bacteria from rows of sputum 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.
Placed inside a glass cage, a rat darts from sample to sample, then stops or rubs its legs, indicating that a sample is infected with a TB causing bacteria. Once the task is complete, it is given a treat through a syringe for a job well done.
Samples pointed out by the rats to contain TB bacteria are then sent for further tests using fluorescence microscopy, a more sensitive laboratory technique. The results are sent back to health centres, allowing patients to start treatment early.
Although TB is a treatable disease, in underdeveloped countries like Mozambique it can be deadly if left untreated and is particularly harmful to people living with HIV. Mozambique is one of the countries worst affected by TB and 1 in 10 adults is HIV-positive.
With World Tuberculosis Day being marked on Tuesday, the Mozambican Ministry of Health said it was cautiously monitoring the APOPO work.
“This technique has to be compared to others that are available and already WHO approved, such as GeneXpert or LED microscope,” said Ivan Manhica, who heads the national programme for tuberculosis at the health ministry.
According to the WHO, TB killed 1.5 million people in 2013.