A trip to the scenic island country of Cape Verde off the coast of Africa has turned into a queasy nightmare for hundreds of tourists returning home. A multi-country outbreak of Shigella bacteria, a common but sometimes serious stomach bug, has been traced back to travel from the island since last fall. Over 200 cases have been documented, including in those returning to the U.S., and some cases are thought to have multidrug resistance to antibiotics used to treat the infection.
Health officials at the European Center for Disease Prevention and Control (ECDC) reported on the outbreak earlier this month. The outbreak seems to have begun in September 2022, but it “evolved rapidly” from November to December.
“Most cases have stayed in five-star, all-inclusive hotels in the Santa Maria region of the island Sal,” the ECDC said in its report.
There have been 221 confirmed cases and another 37 probable cases, affecting people from a dozen countries, including the U.S., the UK, and parts of Europe. No deaths have been reported, but at least one person (in Portugal) was hospitalized as a result.
Shigella is the leading cause of bacterial diarrhea in the world, according to the World Health Organization. Most infections are self-limiting if deeply unpleasant, causing about a week’s worth of diarrhea (sometimes bloody diarrhea, also known as dysentery), cramps, and fever. More rarely, it can cause severe dehydration or other life-threatening complications, with serious illness being more likely in very young children or those with weakened immune systems.
The primary culprit of this current outbreak is a strain of Shigella sonnei, one of the four groups of bacteria that cause disease. Officials still haven’t figured out how the outbreak has spread, though they say that the most likely route is food or water, including through infected food handlers. But more than one method of transmission, including person-to-person contact, may be to blame (sometimes, the infection can even spread through sex). The latest cases were reported from Sweden in mid-January, suggesting that there is still a moderate risk of new infections emerging from Cape Verde, ECDC officials have said.
While most Shigella infections do clear up on their own, severe cases require urgent treatment, including antibiotics. Unfortunately, like many bacterial infections, Shigella is steadily learning how to defeat these drugs. The outbreak strain has shown clear signs of resistance to two antibiotics that have been phased out as frontline treatments, as expected, but some cases have shown evidence of resistance to an even larger variety of drugs.
Despite the relative mildness of Shigella, it still kills around 200,000 people a year, according to the WHO. And given the current and growing threat of the bacteria, many researchers are hard at work trying to develop an effective vaccine against it. Clinical trials of these vaccines are underway around the world—with at least one ongoing study in the U.S. currently looking for people brave enough to chug down a drink containing the bacteria.