There has recently been a new approach to test for tuberculosis. This method is fast, widely available, and cheap. It is the use of large rats to smell the bacteria in a sample. While there are many other ways of testing for tuberculosis many are much more expensive. For example, WHO just endorsed a machine that can produce results in under two hours. But the devise is extremely pricey. It costs $17,000 with an additional $17 dollar cost for each cartridge.
Currently the most common form of testing is called smear microscopy where the sample is dyed with a substance that only colors the mycobacterium tuberculosis which can then be examined under a microscope. Due to the need for a large concentrations of the bacteria these tests tend to result in 60-80% of positive cases going unnoticed.
The rat,
a Gambian pouched rat, thrives in colonies all over sub-Saharan Africa. Their success rate of smelling the presence of TB was 86.6%. When looking to see there was no presence of the bacteria the rats produced a success rate of over 93%. In order to train the rats the researchers have used cognitive conditioning by providing food for the rats when they spend more than 5 seconds at a provided sample with TB which helps them learn to skip over the ones that are not affected. While the results seem remarkable, there is still a lot of skepticism in the medical community.
http://www.nytimes.com/2011/01/04/health/04tb.html?_r=1&scp=1&sq=tuberculosis&st=cse
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