MOROGORO, Tanzania — You may have heard of cancer-sniffing dogs, but would you trust a rat to diagnose you with a serious condition? A new study finds that rats are remarkably efficient at sniffing out tuberculosis (TB) in children — even proving more accurate and effective than the standard microscopy tests doctors typically use.
Researchers showed that when given samples of children’s saliva to sniff, rats detected 68% more cases of TB infections than a simple microscopy, or smear test.
The inspiration for the study comes from anecdotal evidence that those with TB emit a highly-specific odor. Current TB detection methods are far from perfect, especially in areas where the disease can run rampant, such as Southeast Asia and Sub-Saharan Africa. The smear test is used predominately in these areas, and accuracy is a large problem. Children, for example, sometimes can’t produce enough saliva for an accurate reading.
“As a result, many children with TB are not bacteriologically confirmed or even diagnosed, which then has major implications for their possible successful treatment,” explains Georgies Mgode, a researcher from Sokoine University of Agriculture in Tanzania who led the study, in a release. “There is a need for new diagnostic tests to better detect TB in children, especially in low and middle-income countries.”
So Mgode and his team analyzed samples from 982 children under the age of five who were tested for tuberculosis using smear tests in the Tanzanian capital of Dar es Salaam. The smear tests indicated that 34 children had the disease. However, when given to trained rats to sniff, 57 tuberculosis cases in the samples were found. The rats were trained to pick up the scent of TB-causing bacteria in saliva, much in the same way rats are trained to pick up the scent of landmines.
“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%. This is a significant proportion given that these additional patients were considered TB negative in hospitals, hence were initially left untreated,” adds Mgode.
The full study was published April 4th in the journal Pediatric Research.