The battle against pulmonary tuberculosis may have gained an unlikely ally in the African giant pouched rat, a member of the Muroidea rodent super family that includes hamsters, gerbils, mice and the common kitchen rat.
Once trained, the rodents need only 200th of a second to detect a distinctive odour and are already saving lives in Tanzania, according to representatives of Apopo, a Belgian NGO headquartered at the Sokoine University of Agriculture in Morogoro.
Since 2008, Apopo claims to have screened over 97,000 samples in hospitals where the rats are used in secondary screening and have improved detection rates by up to 23 per cent in trials. A trained human laboratory technician can screen about 40 samples a day using a microscope; a pouched rat can screen those many samples in seven minutes, and 1680 samples a day.
The results in Tanzania have been so impressive that the government of Mozambique has invited Apopo to set up a similar project. “We are in the process of setting up a laboratory and training handlers. The programme will kick in by December,” said Tess Tewelde, an Apopo representative, on telephone from Maputo.
In the past few years, a number of scientific studies have attempted to use trained animals such as dogs, bees and now, rats, to detect “biomarkers” that indicate illnesses. The tuberculosis bacteria, for instance, produces distinctive volatile organic compounds that are detected in infected sputum samples by Apopo’s rodents.
Mr. Tewelde and his organisation used the same principle to train the rats to detect landmines in Tanzania, Mozambique and Thailand.
“We have 40 rats in mining operations in Mozambique. So far we have returned over 5.5 million square metres of land to local population and have detected 2,500 mines, 2,200 unexploded ordinances and over 12,500 small arms ammunitions in Mozambique,” he said, “In 30 minutes, our rats can cover an area that can take a fast [human] de-miner over two days.” In a TED talk filmed in June 2010, trainer Bart Weetjens explained that the rats can be trained at a fifth of the cost of a certified mine-detecting dog.