The headlines about Shigella have taken a sharp turn. For most of my career the bug showed up in the news the way I knew it best — a daycare outbreak, a sick restaurant worker, a batch of contaminated produce. Lately the headlines read more like something out of an STI clinic: “sexually transmitted superbug,” “drug-resistant Shigella spreading among gay and bisexual men,” “no antibiotics left that work.” After more than thirty years representing people sickened by foodborne pathogens, I wanted to understand what is actually driving those headlines — and, more to the point, where Shigellaoutbreaks really come from.
The answer is more useful, and less sensational, than the headlines suggest. So let me lay out the sources, one by one. But first, the single fact that explains all of them.
Here is the thing to hold onto before you read a word about “food,” “water,” or “sex” as sources of Shigella: this organism lives in exactly one place in nature — the human gut. Unlike Salmonella (chickens, reptiles, cattle) or E. coli O157:H7 (the digestive tracts of cattle), Shigella has no meaningful animal reservoir. It comes from people, and it goes back into people.
That means every single Shigella infection — whether it’s labeled foodborne, waterborne, sexual, or person-to-person — traces back to the same event: someone else’s feces got into your mouth. The various “sources” you read about are really just different delivery routes for the same fecal-oral trip. Food, water, hands, and sexual contact are all just vehicles.
And it doesn’t take much of a dose. With most foodborne pathogens you need to swallow thousands or millions of organisms to get sick. With Shigella it can take as few as 10. That absurdly low infectious dose is why this bug spreads through households and daycare centers like wildfire, why one sick line cook can sicken dozens of restaurant patrons, and why it moves so efficiently through close personal contact. Keep that number in mind — it explains everything that follows.
There are two species that account for nearly all U.S. infections, and the distinction matters for the headlines: Shigella sonnei (historically the one most often tied to food and water) and Shigella flexneri (the one a growing share of the sexually transmitted cases involve). Same fecal-oral rules, slightly different epidemiology.
For decades the face of shigellosis in this country was a toddler in diapers. Shigella has always thrived in childcare centers and in households with small children who aren’t reliably toilet-trained. Little hands, shared toys, a low infectious dose, and adults changing diapers and then handling food — it’s a nearly perfect transmission system. This is still the most common backdrop for ordinary community spread, and it’s why supervised handwashing in daycare settings remains one of the most effective controls we have.
This is my lane, and it’s where the “human origin” point becomes concrete. Because Shigella comes only from human feces, a foodborne Shigella outbreak almost always means one thing: an infected person handled the food and didn’t wash their hands. When CDC and academic researchers looked at foodborne shigellosis outbreaks in the U.S. over an eleven-year stretch, the pattern was clear — the majority were restaurant-associated, infected food handlers were implicated in roughly a quarter of them, and foods that are served raw or cold and handled heavily during prep (salads, chopped produce, deli items) showed up again and again. S. sonnei drove most of them.
The good news, if you want to call it that, is that foodborne transmission is a relatively small slice of the total shigellosis picture — well under 10% of reported outbreaks — and it is almost entirely preventable. There is no mystery about the fix. A food worker who is sick with diarrhea does not belong in the kitchen. CDC’s guidance is blunt: stay home from the moment you feel sick until at least two days after the diarrhea stops, and don’t go back to handling food until stool testing confirms you’re no longer shedding the bacteria. Every foodborne Shigella case I’ve ever seen was a preventable handwashing-and-sick-leave failure dressed up as bad luck.
Because it’s a fecal-oral bug, contaminated water is a natural vehicle — both drinking water in places with poor sanitation and recreational water closer to home. Swimming pools, splash pads, lakes, and ornamental fountains have all served as Shigella delivery systems when someone with diarrhea contaminates the water and someone else swallows a mouthful. Anyone with diarrhea should stay out of shared water.
Now to the story generating all the attention. Sexual contact is a fully logical route for a fecal-oral pathogen — direct oral-anal contact, or indirect contact through shared objects, transmits Shigella the same way an unwashed hand does. Public health agencies have quietly recognized this for years, particularly among gay, bisexual, and other men who have sex with men. What’s new isn’t that Shigella can be sexually transmitted; it’s the scale, and the drug resistance riding along with it.
In April 2026, CDC published an analysis in its Morbidity and Mortality Weekly Report that put numbers to what clinicians had been seeing. Reviewing roughly 17,000 Shigella isolates from 2011 through 2023, the researchers found that the share classified as extensively drug-resistant (XDR) — resistant to all five recommended oral antibiotics (azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole, and ampicillin) — climbed from essentially 0% in 2011–2015 to about 8.5% in 2023. The demographic shift was just as striking: the vast majority of infections were in adult men, nearly half of whom were living with HIV, and about a third of patients were hospitalized.
A point worth making plainly, because the headlines tend to blur it: framing this as a “gay disease” is both wrong and counterproductive. This is a fecal-oral pathogen following the same biological rules it always has; a particular sexual network simply happens to be where it’s currently circulating and acquiring resistance. One clinician quoted in the coverage made the sharpest observation — Shigella “falls through the cracks” between the STI world and the foodborne-illness world, so a lot of people who are transmitting it sexually don’t even realize it’s transmissible that way. That’s a public health communication failure, not a moral one.
If you only read the “sexually transmitted superbug” stories, you’d miss what some frontline clinicians say is now their single biggest Shigella population: people experiencing homelessness. In Seattle, infectious disease physicians describe Shigella in the unhoused taking off in the early months of the COVID-19 pandemic, when public restrooms closed and people had nowhere to wash their hands or dispose of waste. One Harborview physician said flatly that he now sees more Shigella in people experiencing homelessness than in any other at-risk group. Same bug, same low infectious dose, same fecal-oral route — just a population deprived of the basic sanitation that keeps the rest of us safe. It’s a reminder that Shigella is, at bottom, a disease of broken sanitation, whoever the victim happens to be.
Strip away the Sex in the headlines and here’s what’s left. Shigella is a human-origin, fecal-oral pathogen with a punishingly low infectious dose. Every “source” — daycare, restaurant food, a swimming pool, international travel, sexual contact, an encampment without a working restroom — is the same fecal-oral event wearing a different costume. And nearly all of it is preventable with the least glamorous public health tools we have soap, water, working toilets, paid sick leave for food workers, and a culture that doesn’t pressure sick employees to show up. The headline writers found the sensational angle. The real story is the one that’s been true since 1993: this stuff is preventable, and where it isn’t prevented, someone made a choice not to.