Man Sent to the ICU After Being Bitten by Toilet Rat

A Canadian man found a rat in his toilet, and his month only got worse from there. In a recent case report, the man’s doctors described how he contracted an unusual and severe infection from being bitten by the rodent—one that ultimately sent him to the intensive care unit. Thankfully, he was successfully treated.

The case was detailed this January in the Canadian Medical Association Journal. According to the report, the 76-year-old Montreal resident went to a local emergency department with fever, headache, and abdominal pain that had been ongoing for three days. Almost three weeks earlier, he had the misfortune of encountering a rat in his toilet bowl. When he tried to remove the sewer animal, it bit two of his fingers. The man promptly visited the emergency department, where his wound was treated and he was given a tetanus booster. While the wound itself was healing fine by the time of his second ED visit, tests revealed he had developed sepsis—a type of systemic, life-threatening inflammation often caused by infection—and he was admitted to the hospital’s ICU.

Given the bite and his symptoms, doctors suspected that he had either contracted rat bite fever, an infectious disease caused by several bacteria commonly found in the mouths of rodents, or leptospirosis, caused by Leptospira bacteria. Both diseases can be treated with the same drugs, so the doctors quickly placed the man on intravenous antibiotics while they waited for further testing. Eventually, he was confirmed to have leptospirosis.

Not everyone infected by Leptospira bacteria becomes sick, and the nonspecific symptoms it can cause initially, such as fever, chills, and muscle aches, make diagnosis difficult. Sometimes, people can recover from this first bout of illness but later experience a second phase where the infection severely damages the liver, kidneys, and brain. Severe leptospirosis can have a mortality rate as high as 15%.

What made this case stranger than most is that leptospirosis usually isn’t caught from rat bites. The bacteria isn’t naturally shed in a rodent’s saliva but rather its urine. So people will typically catch it from touching urine directly or being exposed to food and water contaminated by infected urine (this is one reason why flood-causing storms can spark outbreaks of the disease). As best as the doctors can tell, the man’s infection might have come from his furry aggressor having temporarily contaminated its own mouth with bacteria-soaked urine before biting him.

Despite his serious illness, the man responded well to the antibiotics and other treatments. He was discharged from the ICU after three days and completed his remaining course of oral antibiotics with no issue.

Though the bacteria that cause leptospirosis is found everywhere in the world, it’s more often encountered in tropical areas, and human cases are rarely reported in Canada or the U.S. Many animal species can catch and potentially spread leptospirosis to humans, however, including our pets. And the disease is expected to become more common over time, thanks partly to climate change raising the risk of extreme weather events like severe floods.

The case report authors note that there’s no clear consensus on whether to give people prophylactic antibiotics after a rat bite. But given evidence from some studies that antibiotics can prevent leptospirosis in people at high risk of exposure and the fact that bites can spread other bacterial infections like rat bite fever, they argue that clinical trials should be conducted to test this approach.

“Although antibiotic preventive therapy after a rat bite remains an unresolved issue, rat bites could warrant antibiotic prophylaxis because they regularly result in rat-bite fever, and they create puncture wounds that have a higher risk of infection,” they wrote.