The Seattle Times recently examined how researchers in Tanzania are training rats to diagnose tuberculosis by sniffing sputum samples. The researchers' efforts "capitalize" on the rats' strong sense of smell and appetite, according to the Times.
Bart Weetjens, a former industrial designer, developed the idea of training rats to detect TB, as well as land mines, after he visited minefields and saw German shepherds sniffing for buried explosives. Weetjens said that training the rats is simple and that it involves associating a "food reward with a target scent."
The rats, which have an average life span of six to eight years, are indigenous in many parts of Africa and are resistant to local diseases, according to the Times. Low-cost, rapid TB screening using the rats would be valuable in Africa, particularly in areas where clinics lack microscopes, according to Weetjens.
In verification tests, rats were shown to be about as accurate as human laboratory technicians who work with microscopes and 100 times faster at making diagnoses. Weetjens said that in a given week, rats spot five to 10 TB cases that hospital labs missed. Weetjens said he envisions developing mobile rat clinics that could screen samples in refugee camps, prisons and other areas with high rates of TB. Medical workers could then confirm positive samples.
However, the idea of using rats to diagnose TB is facing some skepticism, the Times reports. "When I first suggested it, everyone laughed at me," Weetjens said. Richard Chaisson of the Center for Tuberculosis Research Laboratory at Johns Hopkins University said that although the idea is novel, there are "enormous issues of practicality and feasibility."
Weetjens has acknowledged that there are challenges associated with the method but said that "out-of-the-box thinking can really revolutionize things." Other animals have shown potential diagnostic capabilities, such as dogs that appear able to detect cancer in humans. It is unclear which molecules the animals are detecting, but some diseases can cause scent changes that are detectable even to humans. Weetjens received a grant from the World Bank to build his lab and is hoping to bring in additional donations on his Web site, HeroRat.org, from people who want to adopt individual animals.
Source: Kaiser Family Foundation