No, it's not an April Fool's story. Seriously. Although we're used to thinking of rats as disease-carrying villains of human habitations, not all rats can be classified thus. Take, for example, the giant African pouched rat, known to cognoscenti as Cricetomys gambianus.
Actually they're not really classified as rats, though they certainly are rodents. They can reach up to to three feet in length (including the tail), and weigh up to about three pounds. They're also relatively long-lived (for a rat) — up to eight years.
Their claim to fame is that, as light weight, easily trainable critters, they have proved ideal for detecting land mines without setting them off. This is because the giant rat has poor eyesight, and relies on its sense of smell to navigate the world.
APOPO, a Belgian non-profit NGO based in Tanzania, has been training these animals to detect buried landmines in war-torn areas of Africa since 2000. Now they are also capitalizing on the rat's' ability to detect tuberculosis (TB) in prisoners held in Tanzania and Mozambique, according to a report in The Guardian.
TB is one of the leading causes of death worldwide, and it's already difficult enough to get people screened and treated. Worse still, public health authorities, who already face major obstacles in controlling the disease, now must also cope with strains of TB that are largely, or even entirely, resistant to drug treatment. There are also people who are known to be at high risk of TB, such as those who are HIV-positive or live in shanty towns and prisons.
The rats are being trained to detect the presence of TB in sputum samples, and thus far their accuracy is reportedly close to 100 percent. Detecting TB by the typical laboratory method can take several days, since it's necessary to grow the responsible bacteria in the lab. Once a rat is trained, which can take about nine months, it can screen 100 samples in 20 minutes — obviously a huge savings in time and money for countries that are lacking in resources.
Before these rats become the go-to means of TB detection, however, more information is needed. For example, their accuracy must be confirmed by laboratory testing, which will determine the rates of false positives (identifying a sample as positive for TB when it is not) and false negatives (identifying a sample as clean when it isn't). If these rates are low enough (and maybe lower than lab testing), then the giant African pouched rat may well become a potent weapon in the global effort to conquer TB.