In laboratories situated in Tanzania and Nairobi, an innovative method for detecting tuberculosis has emerged: trained rats. These African giant pouched rats have made a name for themselves in landmine detection and now aim to revolutionize tuberculosis diagnosis.
Collaborating with scientists at the APOPO Project, a Belgian non-profit organization in Tanzania, these rats possess an extraordinary ability to detect the odor of this deadly disease. A study by APOPO in 2016 compared the rats' accuracy to conventional laboratory methods, including smear microscopy, bacteria culture tests, and Genexpert, a rapid tuberculosis test.
Joseph Soka, the program manager for TB at APOPO, emphasizes the rats' exceptional sensitivity, which rivals that of microscopes and other tests. Notably, their sensitivity remains consistent regardless of the HIV status of the individuals they examine. This is especially valuable for diagnosing tuberculosis in HIV-positive patients, who often prove challenging to diagnose accurately using standard methods, including Genexpert and microscopy.
APOPO is renowned for its work in training rats to detect landmines, and its venture into training rats to detect tuberculosis began in 2008. These rats now operate in 21 medical centers in the Tanzanian capital, Dar es Salaam, where they offer faster tuberculosis detection than traditional methods.
In many developing countries, tuberculosis detection still relies on old techniques, such as the use of microscopes to analyze patients' sputum samples. Dhaval Shah, a veterinary pathologist at Pathologists Lancet Kenya, highlights that rats significantly accelerate the testing process. Conventional laboratory techniques can take several hours to as long as 14 days per sample, depending on the method. In contrast, the rats can process fifty samples within two hours, making them ideal for remote or rural areas like Mozambique.
The World Health Organization (WHO) reported that in 2021, tuberculosis claimed 1.6 million lives, including 187,000 individuals with HIV. The disease ranks as the 13th leading cause of death worldwide and is the second leading infectious killer after COVID-19.
In Mozambique, the WHO estimated that in 2018, 162,000 people (equivalent to 551 cases per 100,000 individuals) contracted tuberculosis, underscoring the pressing need for a rapid, dependable, and cost-effective diagnostic technique for the tuberculosis-causing bacteria. The use of rats offers hope for eliminating the necessity of time-consuming microscope testing.