THE BLOG
10/29/2013 05:28 pm ET Updated Jan 23, 2014

Rats against TB

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Tuberculosis (TB) serves as the second leading cause of death from an infectious disease worldwide after AIDS. According to WHO reports, there are three million still unreached people every year, and approximately 8.6 million people fell ill with the disease in 2012, including 1.1 million cases of people living with HIV. StopTB reports that 9 million people become ill with TB each year and more than a million and a half people die from TB related illness.
TB treatment has saved the lives of more than 22 million people, and APOPO plays a crucial role in TB detection in Tanzania and Mozambique, two countries with a high TB burden. APOPO saves lives through the deployment of detection rats technology. It aims at accelerating TB detection by retesting TB suspected samples after local clinics have finished with them (second-line screening). Its first TB research lab was established in Morogoro, Tanzania in 2005, and since 2008, the HeroRATs have delivered very promising results, with a reported increase of 43% in the tuberculosis detection rates in the samples evaluated. With the aim of replicating the results obtained in Tanzania, APOPO opened operations in the Republic of Mozambique earlier this year. There are currently 8 accredited rats in Mozambique at the moment, and since January, over 11,000 sputum samples have been evaluated.
The rats can screen more samples in 10 minutes than a microscopy lab technician can get through in a day. Since APOPO began its operations, the rats have screened almost 200,000 samples, from 16 clinics in Dar es Salaam alone and identified over 4,000 TB positive patients initially missed by microscopy in the clinics. However, tracking down and treating patients who have been sent home from the clinics based on a negative microscopic test is a major challenge so to tackle this APOPO established a partnership last year, with a Tanzanian NGO called Mapambano ya Kifua Kikuu na Ukimwi Tanzania (MKUTA), which was formed by former TB patients. Because of their own TB histories, MKUTA volunteers are able to highlight the importance of providing the clinics with reliable contact details and this enables finding them at a later stage.
It takes about nine months to fully train a tuberculosis detection rat. It is an exciting, interesting process, beginning with socialization, where the handlers carry the young rats around with them in everything they do for two weeks (to accustomise the rats to working with human beings) to click training , (where the rats learn to associate the click sound with a food reward), then a scent introduction to mycobacterium tuberculosis TB, which they have to identify before they get their food reward. After that they are introduced to three holes, with a mixture of positive and negative samples. Once a rat can fully correctly identify positive samples amidst negative ones correctly, they have to pass an accreditation test, which will then allow them to serve as second line screening for the TB centers, which check for TB under a microscope. Currently APOPO's rats are operational in Tanzania and Mozambique, and both countries are among the 22 countries that account for 80% of tuberculosis cases in the world.