They are often considered pests and associated with plague and pestilence. But now the rat is spearheading a revelatory new disease-detection method which could help save thousands of lives in Africa and across the world.
The man behind the idea of using African giant pouched rats to quite literally sniff out tuberculosis (TB) is Bart Weetjens. Weetjens established APOPO (Anti-Personnel Land Mines Detection Product Development Program) in Tanzania, after he had the idea of using rats to clear Mozambique, Tanzania and other countries of the landmines left after conflicts.
APOPO has now managed to train rats to accurately identify the TB virus in human sputum samples and, after successful trials earlier this year, is set to take its cost-effective, virus-detecting rodents to Mozambique, a country with a high TB incidence of an estimated 431 cases per 100,000 people.
This technology has come at an opportune time as TB is now one of the biggest killers in Africa. APOPO founder Bart Weetjens was recently quoted in the press as saying he first mooted rat-based technology when he saw a 2002 World Health Organization report that predicted TB deaths would quadruple to 8 million by 2015.
Currently, tuberculosis kills nearly 2 million people worldwide each year. And in Southern African countries, the combination of HIV/AIDS and TB is the cause of thousands of deaths; TB is particularly fatal when it is able to attack immune systems that have been already severely weakened by diseases such as HIV and AIDS.
One crucial battle in overcoming TB is early detection in order that the spread of the disease can be abated. If left untreated, a person with active TB can infect 10-15 people each year.
In Tanzania, APOPO has been using rats for second-line screenings. This project has increased new case detection rates by over 40 percent and rats can evaluate up to 40 sputum samples in just seven minutes. A skilled lab technician, on the other hand, would take an entire day to process 40 samples using the accepted detection method of microscopy.
The concept is simple: rats smell a series of samples dishes in which human sputum has been lined up for evaluation. They identify samples that contain TB bacteria by scratching at the sample dish. Previously unidentified samples, if pinpointed by two rats or more, are then confirmed by scientists using microscopy. Samples that are positive with TB are returned to the hospitals who then inform the associated patient(s) of the diagnosis and issue treatment.
“At this stage, APOPO's TB detection program is in a research phase. Proof of principle has been established, and we're now working towards further validation of the technology before full implementation. However, since the start of operations, APOPO's HeroRATs have already identified over 2,232 TB-positive patients that were initially missed in first-line screening by microscopy. On a weekly basis, our rats find an additional 5 to 15 new TB-positive patients,” explains a statement from APOPO.
In 2010, APOPO commenced work on a three-year research plan, which includes experiments using this detection method to various other diagnostic technologies. It is closely examining how effectively its rat-based method detects TB, as well as the costs involved per sample. “Our aim for the next three years is to further optimise this TB detection technology and focus on implementation models for the future,” APOPO said.
Following its recent successes, APOPO’s proposal to expand the TB Detection Program into Mozambique has been approved by the Flemish government; it has awarded APOPO a grant of €590,000 ($787,000) to implement the first phase of the project.
“We recently received funding from the Flemish Government to replicate this program in Mozambique. An initial visit by members of our team will be made to Maputo, Mozambique in the coming weeks, and we are in the process of hiring a programme manager that will lead the new program in Mozambique. We hope to start in 2012,” APOPO communications manager Hannah Ford revealed to Think Africa Press.
In the short term, APOPO aims to significantly increase the rate of new TB case findings in Mozambique by replicating the success of their TB Detection Program in Tanzania. The first phase of this new project will involve implementing collaboration agreements, establishing an operational TB detection facility, and evaluating the efficacy of the established operation. If successful, APOPO's giant rats may help curb the spread of the age old disease in Mozambique and prove to be indispensable warriors in the battle against TB.
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