In this laboratory in Dar es Salaam, these rats are considered heroes. Trained to sniff samples of human sputum, they manage to identify tuberculosis in people living with HIV.
This project called APOPO, from a Belgian NGO was initiated in 2008, today the animals are used in 21 medical centers in the capital of Tanzania. According to this scientist Joseph Soka, head of the TB program at APOPO, the ability of his rodents to detect pathogens is high due to their impressive sensitivity to smell.
“The sensitivity of these rats is as high as that of microscopes and compared to other tests, their sensitivity is independent of HIV status. That is, they can easily identify tuberculosis in people living with HIV. , knowing that these people living with HIV, it is very difficult to be diagnosed by the standard test, including the Genexpert in the microscopes.”
A study carried out by this NGO in 2016 shows rats are 75% more accurate at detecting tuberculosis than standard laboratory methods such as smear microscopy, bacterial culture tests or the Genexpert – a rapid test for tuberculosis. This is explained by their nasal mucosa covered with 50% of olfactory receptors, which explains their superior ability to detect odors compared to humans who have only 5%.
“So conventional lab techniques can take between two hours or even 14 days per sample, depending on the technique used, whereas rats will be able to complete the test of fifty samples in two hours and this would be ideal in remote places or remote places like Mozambique or places in Mozambique that are rural,” said Dhaval Shah, pathologist.
This laboratory plans to carry out a new study, because the previous one had certain shortcomings. Her staff is convinced that she will demonstrate that the sensitivity of these rats can reach 90%, for an approval of this method by the World Health Organization.