A new study by the Sokoine University of Agriculture in Tanzania showed that trained rats can identify tuberculosis (TB) in children more accurately than conventional microscopy tests.
The research is based on the anecdotal evidence that TB patients emit a specific odour and is intended to address the challenges with commonly used diagnostic methods, such as a smear test that is cheap but reported to be inaccurate.
According to the researchers, the existing tests are limited due to the quality of sputum samples – a mixture of saliva and mucus coughed up from the respiratory tract – used and very young children usually cannot deliver the required amount.
The latest study involved African giant pouched rats that were trained to detect the scent of molecules discharged by the TB-causing bacterium, Mycobacterium tuberculosis, in sputum.
Out of a total 982 sputum samples from children, the rats were able to detect 68% more cases of TB infections compared to a standard smear test.
Published by Springer Nature in Pediatric Research, the findings were confirmed using advanced light emitting diode fluorescence microscopy.
Sokoine University of Agriculture researcher Georgies Mgode said: “There is a need for new diagnostic tests to better detect TB in children, especially in low and middle-income countries.
“This intervention involving TB screening by trained rats and community based patient tracking of new TB patients missed by hospitals enables treatment initiation of up to 70%.”
A possibly infected sample identified by a rat will be further examined using WHO endorsed concentrated microscopy techniques to validate the positive diagnosis.