Is Diarrhea Contagious?

A sudden, unexpected bout of diarrhea is both unpleasant and uncomfortable. According to the Cleveland Clinic, diarrhea can fall into one of three categories depending on how long symptoms last: acute, persistent, and chronic.

Acute diarrhea is common among most adults and generally takes care of itself within a couple of days to a week (via National Center for Biotechnology Information). Acute cases of diarrhea may be triggered due to external factors, such as eating food the body isn't used to eating or as a side effect of certain prescription medications. Meanwhile, cases of persistent diarrhea can last between two to four weeks, while chronic cases of diarrhea can persist for over four weeks.

For those untimely cases of acute diarrhea that seemingly come out of nowhere, sometimes a viral or bacterial infection may be to blame (via NCBI). In a 2017 study, researchers from the ​​Brigham and Women's Hospital determined that diarrhea is an immune response by the body in order to rid itself of pathogens at the onset of infection. But as our body goes to work shedding these pathogens, is it possible that we're contagious to others in the process?

Unfortunately, acute cases of diarrhea due to bacterial or viral infection are often highly contagious (via Health). The highly transmissible norovirus, for example, is responsible for 50% of diarrhea infection outbreaks, as it is easily contracted within contained environments such as hospitals or dormitories, per a 2014 review published in the New England Journal of Medicine. Cases of diarrhea caused by bacterial infection can also be contagious, with research showing salmonella pathogens to be detectable in fecal matter for as many as 30 days following infection (via ETH Zurich).

Gastroenterologist Dr. Carolyn Newberry tells Health that diarrhea is contagious through a process known as fecal-oral transmission, in which particles of infected fecal matter make their way into the mouth of a new host. Acute cases of diarrhea that cannot be attributed to external circumstances or a pre-existing health condition are likely contagious.

Therefore, you'll want to take care to avoid spreading the infection to others. Frequent hand washing, sanitizing of commonly touched surfaces, and avoiding close contact with others can help reduce the likelihood of transmission. Gastroenterologist at NYU Langone, Dr. Lisa Ganjhu, stresses the importance of keeping the bathroom clean and sanitary, stating via Health, "It's very important that if that person uses the toilet, to make sure you bleach down all the surfaces to kill any potential cross contamination."

While rest and rehydration are often enough to help a spell of diarrhea pass on its own, if you experience accompanying symptoms such as dizziness, fever, vomiting, weakness, rash, or blood in your stool, or if symptoms worsen or persist, be sure to consult with a medical physician (via Cleveland Clinic).