Saturday, April 2, 2016 6:38 am
Scientists in East Africa are planning to exploit trained rats’ highly developed sense of smell to carry out mass screening for tuberculosis among inmates of crowded prisons in Tanzania and Mozambique.
Health officials noted on Friday in Dar Es Salaam that this has became imperative because in Tanzania, people in communities where TB is most common, including prisons, often fail to show up for screening due to paucity of funds or awareness.
“Tuberculosis is the leading cause of death, after HIV, from an infectious disease around the world.
“The WHO data shows that there are about 9 million new cases a year and around 2 million deaths,”they said.
They said this is creating a huge burden for health authorities trying to tackle the disease.
The health official said because existing systems lack the accuracy, speed and cost-efficiency required scaling up screening of the highly contagious disease, many TB cases go undiagnosed.
They disclosed that to achieve this, African Giant Pouched Rats trained by the Belgian non-governmental organisation “APOPO’’, widely known for their work sniffing out landmines, are now developing a reputation in East Africa for their skill and speed at detecting TB too.
Charlie Richter, APOPO’s U.S. Director, said with funding from the United States Agency for International Development (USAID,) plans are underway to recruit and train more rats to carry out prison screening.
He said the system is faster and more reliable than existing methods.
“We believe our unique TB Detection Rat technology will prove itself as an effective mass-screening tool.
“We then aim to expand the programme to all prisons, shantytowns, factories and other settings in Tanzania, Mozambique and other high TB-burden countries, as well as in high-risk groups such as those individuals living with HIV/AIDS.
“This will improve and save lives all over the globe at a low cost,”he said.
Richter said the rats undergo a rigorous training process that begins when they are four weeks old.
“As soon as the rats open their eyes, they are introduced to various stimuli and learn how to socialise and interact with people.
“The rats learn to recognise the presence of TB in samples of sputum, mucus that is coughed up from the patient’s lower airways, and rewarded when they succeed,”he said.
Richter said the testing process starts when a rat is presented with a row of 10 sputum samples, and when it detects TB the rat hovers over the sample for 3 seconds.
“The rats’ accuracy at detecting TB is almost 100 per cent, but they cannot distinguish between normal and drug-resistant strains.
“The APOPO system is fast, cheap and has the potential to greatly lower screening costs in poor countries.While a laboratory technician may take four days to detect tuberculosis, a trained rat can screen 100 samples in 20 minutes, and a rat screening can cost as little as 20 cents when APOPO operations are running near capacity,” he said.