Rats don't have the best reputation when it comes to diseases. But giant rats are actually being used to detect and prevent tuberculosis (TB) with a huge amount of success. Even more recently, they’ve specifically turned their noses to sniffing out the disease in East African prisons.

The idea of utilizing rats' keen sense of smell has been taken up by APOPO, a Belgian NGO. It currently has 50 “fully qualified” African giant pouched rats that have undergone up to nine months of training at its headquarters in Morogoro, Tanzania. When fully trained, the rats can work through over 100 samples in 20 minutes. For a skilled human lab technician, this would take over two days.

The process starts by collecting samples of phlegm. These samples are then put in a heated autoclave to deactivate any potential pathogens that could harm the rats or handlers. Rats are then put in front of a line-up of the samples, as you can see in the image below. If they hover over a sample for more than three seconds the sample is suggested to contain TB and it is sent off to a lab for further analysis.

Not only is the process quicker and cheaper than “conventional” means, it’s also considerably more accurate. APOPO say that the rats' accuracy is near to 100 percent, although they cannot distinguish between normal and drug-resistant strains.

^{A rat at work, smelling some potential TB samples. Briana Marie/APOPO's HeroRATs}

The impact has so far been extremely impressive. APOPO estimate they have screened 344,919 samples for tuberculous and successfully halted 39,920 cases.

Tuberculosis is now the most prolific and deadly infectious diseases in the world, having surpassed HIV last year. In parts of East Africa, such as Tanzania and Mozambique, this easily preventable disease is allowed to prosper through a lack of public awareness and underfunded projects. It’s also estimated that inadequate diagnostic tests in these areas miss almost half of TB cases. This is particularly true of the countries’ densely populated prisons. As such, Reuters reports APOPO's latest project is aimed at prison populations in Tanzania and Mozambique. 

Charlie Richter, APOPO’s U.S. director, told Reuters: “We believe our unique TB Detection Rat technology will prove itself as an effective mass-screening tool.”

He added, “We then aim to expand the program 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.” 

The NGO previously gained notoriety for its work using rats to detect landmines. This equally successful initiative also operate in East Africa, as well as parts of Thailand, Vietnam, Cambodia, and Laos. You can read more about the land mine projects on APOPO's website.

They also regularly update their Twitter and Instagram pages to promote their cause and share their latest developments.

^{Although they work hard, APOPO pride themselves on the welfare of their rodent co-workers. APOPO's HeroRATs}