Rats are trained to sniff out tuberculosis

Rats can detect tuberculosis better than the best doctors.

TB is a disease caused by a bacterium called Mycobacterium tuberculosis and infects one in three people worldwide. Traditionally, samples are examined under a microscope, and can take weeks to turn up results.

Not only that, but it can be quite costly.

Nicholas Bakalar writes in The New York Times that "the World Health Organization recently endorsed a new machine that can give accurate results in under two hours. But the device costs $17,000, and each test requires a $17 cartridge."

As it turns out, the 15-pound rats can do a good job of detecting the presence of TB. The chubby, cheek rats have poor eyesight, but they have a keen sense of smell. The rats have been previously trained to sniff out land mines.

In this case, scientists trained giant African pouched rats to detect TB in sputum samples previously taken from more than 10,000 patients.

When the scientists compared the rats' ability to detect TB to the accuracy of using standard microscopy techniques, the rats actually had good instincts. Microscopists found 13.3 percent of patients to be TB-positive, while rats increased the detection rate to 19 percent. The rats found 620 new cases, and increased the detection rate of positive cases by 44 percent.

The results were published in The American Journal of Tropical Medicine and Hygiene.

However, it's not like the rats that were used in the experiment were yanked out of the wild. The scientists had to train captive-bred rats for about six months. When a sample was put near the cage, the rodents were rewarded with bananas or peanuts if they spent five seconds at a positive sample.

There's no word on how much rats would cost...although it's not exactly priceless considering all the training involved. Well, you can be the ultimate judge. The rats could tell that TB was present 86.6 percent of the time. And the rats could tell that the germ wasn't there, 93 percent of the time.

However, some experts question this low-tech method as the ultimate test. The researchers are a little more hopeful, and think there's a good chance the rats could be used as a first line of detection at the very least.

Photo: Wikimedia Commons

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This post was originally published on Smartplanet.com