Rats have an extraordinary ability to "sniff out" tuberculosis.

Surprising reports from Tanzania. Rats can "sniff out" whether a child has tuberculosis. Interestingly, they are more effective at this than the commonly used basic microscopy text.

These are the conclusions reached by Georgies Mgode's team from the Sokoine University of Agriculture in Tanzania.

Test

Trained rats were given samples of children's sputum to sniff. The rodents were able to detect as many as 68% more cases of infection than could be detected with a standard swab test. The study was prompted by the hypothesis that people suffering from a potentially fatal lung disease emit a distinctive odor.

Standardized tests

According to Mgode, current methods for detecting tuberculosis are far from perfect, especially in Southeast Asian countries, where the disease is common and relatively inexpensive smear tests are used to confirm it. The problem with this test is that its accuracy depends on the quality of the sputum sample. Very young children often cannot provide enough sputum for analysis.

The need for a new diagnostic method

As a result, many children with tuberculosis remain undiagnosed and unconfirmed. This, in turn, has serious implications for their potential successful treatment. Therefore, new diagnostic methods are needed to better detect tuberculosis in children.

Experiments with rats

Previous work by scientists from Tanzania and Mozambique focused on training giant rats (Cricetomys ansorgei). They trained them to pick up the scent of molecules released by the bacterium Mycobacterium tuberculosis, the bacterium that causes tuberculosis. The training technique was similar to that used to train rats to detect vapors released by explosives. In the case of tuberculosis, when a rat identifies a potentially infected sample, it is sent for further analysis. WHO-approved techniques are then used to confirm a positive diagnosis.

Results

Sputum samples were obtained from 982 children under the age of 5. The children had previously undergone tests for tuberculosis. Sputum swab tests revealed that 34 of the children had the disease. When the same samples were administered to rats, an additional 57 cases were detected. Microscopic examination confirmed the rodent findings.