Not every Apopo rat is a mine-detection expert. While Mourinho and his colleagues scan the countryside, Galina can be found 1,000km south in the capital, Maputo, sniffing busily for the aroma of tuberculosis from saliva samples in a glass cage at Eduardo Mondlane University.
Although the samples have already been tested by conventional microscopy at health centres, Galina and her eight rodent co-workers detect many missed cases of the disease, which killed 1.5 million people worldwide in 2013. Mozambique is ranked fourth in the world for TB prevalence, with a 2011 estimate indicating of 548 cases per 100,000 inhabitants.
"The rats are really increasing the detection rate of TB, which means people get care sooner," says Dr Emilio Valverde, programme manager of Apopo's TB research facility in Mozambique, which opened in 2012. If a clinic detects 100 cases, the rats will detect up to 50 more, he says. "And a rat can evaluate 100 samples in 20 minutes – this is the work of a lab technician in three to four days."
Galina’s reward for highlighting a positive sample is a treat of banana and avocado, fed to her in a syringe through a hole at the side of the cage, before she scuttles back to work. Her job operates on the same principle as demining: each rat is trained to identify the bouquet of TB from sputum samples – which are heat-treated to kill pathogens – and to associate the smell with a clicking sound and food.
If two rats identify TB in a sample, the result is confirmed using LED microscopy, and the patient is alerted. So far 13 health units have joined the project, and since January its nine rats have screened nearly 40,000 sputum samples.
There is talk of them one day sniffing for cancer and other diseases, and even working at airports as drug detectives. That may be down the road, says Valdverde. “Our objective now is to demonstrate that this technique is reproducible, so we want to collect as much scientific data as possible.”
Rat trainer and lab worker Lila Dinis places a frisky Gardénia into the glass case to get sniffing. “People thought it was strange when I began working with rats. But then they saw the pictures and said, ‘Oh, they are very cute.’ And they are. But they are also saving lives.”