The mutant stomach bug that’s reportedly sickened more than 100 people in the Bay Area, sending at least a dozen to the ICU, is well known to international travelers who have experienced stomach issues but has only become a concern to U.S. health officials in the last few years.
The medical name is Shigella sonnei. It's one of the bacteria that causes Shigellosis, which is often linked to many travelers’ stomach cramps, diarrhea and nausea. Public health officials said Thursday 110 cases stemming from a Mexican seafood restaurant in downtown San Jose have been reported in four Bay Area counties.
The majority of the cases are primary, health officials said, meaning most of the people infected ate at Mariscos San Juan No. 3 on Oct. 16 and 17.
Shigella causes about 500,000 cases of diarrhea in the U.S. each year, according to the Centers for Disease Control and Prevention – no small number. But it’s a drug-resistant form of the intestinal bug that is making federal officials worried, NBC News reported earlier this year.
“Research by the CDC found that the drug-resistant illness was being repeatedly introduced as ill travelers returned and was then infecting other people in a series of outbreaks around the country,” the CDC said in a statement back in April.
An antibiotic-resistant strain of the Shigella bacteria sickened 243 people in 32 states and Puerto Rico between May 2014 and February 2015, the statement said. Before last year, only 2 percent of cases were resistant, compared to 90 percent of the samples tested in recent outbreaks in Massachusetts, California and Pennsylvania.
"Drug-resistant infections are harder to treat and because Shigella spreads so easily between people, the potential for more — and larger — outbreaks is a real concern," CDC director Dr. Tom Frieden said in the April statement.
While most of the illnesses reported during the most recent Bay Area outbreak are directly linked to people who ate food that health officials suspect was handled by a contaminated worker, “Shigellosis is very contagious and can spread quickly through communities,” according to the CDC. Shigella germs appear in the fecal matter of those infected, the CDC reports, and even an amount too small to see could cause infection.
Most cases go away without any need for treatment, NBC News reports. But it's critical to have the option, especially in severe cases and individuals whose immune systems are compromised, such as HIV or cancer patients.
Thorough hand-washing is the best way to prevent the spread of infection, according to the CDC.
More information about Shigella — including symptoms and prevention tips — is available on the CDC website.