You’ve likely heard of lab rats, but detection rats technology? APOPO, a Belgian non-profit, with headquarters in Tanzania, breeds, trains, and implements landmine and tuberculosis detection rats in Africa and Asia. Equipped with exceptional noses, African Giant Pouched rats have helped clear over 26 million square meters of land, including nearly 100 thousand landmines destroyed in Mozambique, Angola, Cambodia, Thailand, and Vietnam. Once ravaged by civil and international wars, these lands are now suitable for community use.
Tuberculosis (TB) kills over a million people annually. In countries such as Tanzania and Mozambique, prevalence of tuberculosis is high while detection and treatment are low. This discrepancy is attributable to a lack of diagnostic equipment, trained staff, and lagging infrastructure and utilities. A trained tuberculosis detection rat – otherwise known as a HeroRAT – can screen 100 samples in 20 minutes. The same task would take a trained technician 4 days. In Tanzania alone, over 8 thousand positive TB samples that were missed by technicians were identified by HeroRATS.
Could programs like APOPO fundamentally change the way we think about rats and their role in public health? To find out, we must first take a look back at our long, intertwined history, past traditional research laboratories, and into a future where rats may well be our colleagues.
Wherever people make a home, rats are sure to follow. Inveterate opportunists, rats make good use of our infrastructure and food system with enviable aplomb. What works for rats hasn’t always proved advantageous for humans. Take for instance the Bubonic Plague of the 14th century. Long blamed for the disease that raised black, fetid boils and led to the swift demise of two-thirds of Europe’s population, rats are still synonymous with scourge, despite mounting evidence that implicates gerbils for harboring the fleas that carried the Plague. An even more compelling argument suggests that at its most virulent, the Plague spread human-to-human. This theory is supported by records that show that deaths increased in the winter months, a time when most rodent populations would dwindle considerably.
The story of rats next takes us to the laboratory of University of Wisconsin professor, E. V. McCollum. The year is 1908 and McCollum has just purchased 12 albino rats to further his research on nutrition. Though he has been studying cows for some time, McCollum feels rats will be superior due to the ease of housing, feeding, breeding, and disposal. McCollum might not yet realize that his will be the first of many rat colonies established for research. The first experiment involves splitting the rats into two groups and feeding them different diets. For a time, all rats will develop normally, until one group ceases to grow. McCollum postulates the existence of a factor present in some foods that promotes extended growth. He calls this “factor A,” known today as Vitamin A.
McCollum’s next success would come at Johns Hopkins University’s newly established Department of Chemical Hygiene, later renamed the Bloomberg School of Public Health. McCollum and colleagues used diet to induce Rickets in rats. Rickets, a disease that causes crippling bone deformities, was common among the children of tenement-dwellers in urban centers. Believed to be caused by diet and environment, McCollum prescribed over 300 diets to his Rickets rats and found that those supplemented with cod-liver oil improved. He also found that rats that had daily sun exposure fared better than those left in the dark. McCollum named this new discovery Vitamin D.
Advents in technology revealed increasingly subtle yet deeply profound insights into human physiology. DNA sequencing and genetic engineering allow scientists to simulate human diseases in rats, including cancer, Alzheimer’s Disease, cardiovascular disease, and diabetes. Modern medicine owes much of what it knows about the etiology and treatment of these diseases to laboratory rats. One reason for rats’ success as research subjects in human disease is the genetic and physiological similarities we share, so similar in fact that it is not surprising to learn that all mammalian life plausibly shares a single, rat-like ancestor .
Recent studies venture past the scientific and into the silly. Rats exposed to the psychoactive ingredient of marijuana are less likely to perform a complex task in favor of a simple task with a smaller reward. The rat’s ability to complete the harder task is not affected, just his willingness to exert cognitive effort. Sound familiar?
Ever wonder if rats laugh when tickled? Dr. Jaak Panksepp thinks they do and has video to prove it! Panksepp, a neuroscientist at Bowling Green State University, finds that young rats laugh when tickled and will seek out a tickling hand over a still one. He also learned that rats read environmental cues when it comes to laughter. Just as you or I wouldn’t laugh at a funeral, a young rat won’t laugh under a bright light or with the odor of cat urine in the air.
Science might ultimately prove that rats are better people than us. Scientists wanted to know if rats would help another rat in distress, thus displaying empathy and altruism. One experiment trapped one rat in a clear tube to determine if the other rat would free it by opening a door with its nose. In a riskier experiment, rats on a dry platform were tasked with opening a door for a rat frantically treading water on the other side. Even when enticed by treats, rats overwhelmingly chose to help friends and strangers alike.
When it comes to rats, there is much more than meets the eye. Are they simply a tool to be confined to the laboratory, or might we find them suited to a diverse range of tasks, such as with APOPO? If science has shown that rats laugh, are good Samaritans, and exhibit free will, might we need to reexamine our relationship inside and outside the lab?
Watch this Ted Talk by APOPO founder, Bart Weetjens: How I Taught Rats to Sniff Out Landmines.
From American Cheese to Vitamin A, check out 100 Objects That Shaped Public Health (and yes, rats made the list!)