After seven remarkable years of service detecting tuberculosis (TB) cases that medical tests had missed, Carolina, an extraordinary African giant pouched rat, has retired with honors. Her colleagues celebrated her departure with applause and cake this past November, marking the end of an impressive career that saved countless lives.
During her tenure, Carolina identified over 3,000 TB cases that health clinics had overlooked, potentially preventing more than 30,000 additional infections. Her extraordinary sense of smell allowed her to screen 100 sputum samples in just 20 minutes - a task that would take a human technician four days using a microscope.
Carolina belongs to a specialized team of 40 rats working with the nonprofit organization APOPO in Tanzania and Ethiopia. These remarkable rodents have dramatically improved TB detection rates by 40 percent at local clinics, where traditional testing methods are often only 20-40 percent accurate.
The African giant pouched rats are notably different from common urban rats. With bodies longer than a 13-inch laptop and equally long tails, they possess an incredible sense of smell that can detect minute traces of substances - equivalent to finding half a drop of chlorine in 20 Olympic-sized swimming pools.
Last year alone, these specially-trained rats prevented nearly 400,000 new TB cases in Tanzania and Ethiopia. Their impact is particularly notable as TB remains the leading cause of death worldwide from a single infectious disease, with over 50,000 deaths recorded in these two countries in 2023.
The rats undergo intensive training using positive reinforcement techniques, learning to identify specific TB-related compounds among countless other scents. Their remarkable accuracy requires them to pass a rigorous test - evaluating 500 samples without missing a single positive case - before qualifying for active duty.
Carolina now enjoys her well-earned retirement in a spacious outdoor enclosure alongside Gilbert, another retired TB detection rat. Their "Florida-style retirement community" features regular enrichment activities and special toys crafted by dedicated team members.
"Not only are we saving people's lives, but we're also changing perspectives and raising awareness about these remarkable animals," says Cindy Fast, APOPO's head of training. "Our rats are our colleagues, and we truly see them as heroes."