Tanzania trains rats to detect tuberculosis
Deodatus Balile, SciDev.Net
[DAR ES SALAAM] Scientists in Tanzania have successfully trained rats to
detect tuberculosis (TB) in human saliva by smell, using techniques first
developed to teach the animals to find landmines.
The project has been carried out at the Sokoine University of Agriculture in
Morogoro. Researchers found that while a laboratory technician, using a
microscope, can analyse only 20 samples of saliva a day, a trained rat can
analyse about 120 to 150 samples in just 30 minutes.
"Millions of people worldwide suffer from TB," says the project
director, Bart Weetjens. "To them and their relatives, this [discovery] is
very good news, and we have started to receive calls from all over the
world."
Both wild and laboratory-bred rats (Cricetomys gambianus) required
four to six months of training to be able to detect TB bacteria successfully.
According to Weetjens, it requires little human skill to train them, as the rats
only have to be exposed to the smell that they need to recognise.
The research was carried out last year using samples of human saliva from
patients in the Muhimbili National Hospital in Dar es Salaam, and Morogoro
Regional Hospital.
Weetjens adds that the main challenge is now to generate a sufficient supply
of trained rats. He says that the World Bank has agreed to provide a grant of
more than US$160,000 to help achieve this.
According to the World Health Organisation, worldwide deaths from
tuberculosis are expected to increase from 2 million this year to 8 million by
2015. The situation has been exacerbated by the close association between TB and
HIV/AIDS.
Weetjens points out that since about 40 per cent of the 60,000 Tanzanians
suffering from TB are HIV-positive, detecting TB at an earlier stage raises the
chance of securing effective treatment for both diseases.
He says that it is the speed and accuracy with which the rats can detect the
TB infection that has encouraged researchers. "With this discovery, TB
patients will be able to undergo early treatment in large numbers," he
says.
The university has already trained about 300 rats to detect landmines, but only
a few are trained to detect TB bacteria. The World Bank grant will make it
possible to train up to 400 rats for TB detection.
Part of the grant will also be spent on building a new laboratory for TB
testing at a centre run by Apopo, a Belgian-funded research group based in
Antwerp that runs the landmine training centre. Twenty rats have already been
sent to Mozambique, where they are currently engaged in detecting landmines left
over from the country's civil war.
Weetjens points out that rat detection of TB is a cheap and affordable
technique, as the animals have a highly developed sense of smell, and are easy
to tame and train, as well as to maintain and transport. Furthermore they are
found all over the African continent, adapt easily to new environments, and
appear to enjoy performing repetitive tasks.
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