Shigella Surge? What to Know About Drug-Resistant 'Sexually Transmitted Diarrhea'

The internet has been buzzing about sexually transmitted diarrhea. If you've scrolled through health news in recent days, you've likely encountered alarming headlines about a Shigella surge, drug-resistant strains, and rising case counts. The reality, according to federal disease tracking data, is more measured—and yet still serious in ways that deserve attention.

Shigella is a bacterium that causes shigellosis, an infection of the digestive system marked by acute diarrhea, fever, stomach pain, and sometimes complications severe enough to require hospitalization. The illness spreads easily between people through contaminated surfaces, food, water, or microscopic fecal particles. A person needs only a small amount of the bacterium to become sick. Most people recover at home, though symptoms—which typically begin one to two days after exposure—can last anywhere from a few days to four weeks or longer. The bacteria can be shed in stool for up to two weeks after symptoms disappear, making infected people contagious even as they feel better.

As of September 26, 2026, the Centers for Disease Control and Prevention had recorded 13,921 cases of shigellosis in the United States. That number sits roughly even with the previous year's total of 14,277 cases. The recent surge in headlines and social media posts appears to stem from one or two sources revisiting existing research about drug resistance and antibiotic-resistant strains, reigniting public interest rather than reflecting a genuine spike in infections. The CDC did publish a report on drug-resistant Shigella in April, and related studies have emerged over the past year or two, but the current wave of attention is largely a product of information cycling through the internet rather than new outbreak data.

What has genuinely shifted, however, is the bacterium's resistance to treatment. In 2011, zero percent of tested Shigella samples showed extensive drug resistance—meaning resistance to all FDA-approved antibiotics. By 2023, that figure had climbed to 8.5 percent. This matters because it means some infections have become far harder to treat. The vast majority of these extensively resistant cases, 86.2 percent, occurred in men. Recent research, including a study published in The Lancet Infectious Diseases in July, found that drug-resistant strains are significantly more prevalent among men who have sex with men. By the end of a 2015-2020 study period, roughly 70 percent of sexually transmitted Shigella strains showed resistance to at least one antibiotic, compared to 40 percent among non-sexually transmitted cases and 49 percent among travel-related infections.

The emergence of sexual transmission as a significant route for Shigella spread is relatively recent. For decades, most U.S. cases occurred in children under five or in people who had traveled internationally or been exposed to travelers. Around the turn of the century, experts began documenting its spread through sexual contact—something scientists knew was theoretically possible but believed happened rarely. That assumption has proven wrong. The mechanism driving resistance in these communities involves what researchers call bystander resistance: when the wrong antibiotic or incorrect dose is used to treat Shigella, or when an antibiotic prescribed for another condition fails to eliminate the bacterium, the germ survives and develops resistance.

Certain populations face elevated risk. The unhoused and children under five are particularly vulnerable. Health experts in both the United States and the United Kingdom have begun sounding alarms about the trajectory of the disease. One Cambridge University researcher noted in a July press release that Shigella has shifted from being readily treatable with standard medications to becoming nearly untreatable within roughly a decade. Many men who have sex with men remain unaware of the growing risk posed by sexually transmitted Shigella, experts say, making targeted public health messaging essential.

Prevention remains straightforward: thorough hand washing with soap and running water after using the bathroom, changing diapers, before and after handling food, and before and after sexual contact. People should avoid swallowing water in pools, lakes, rivers, or ponds. If someone becomes sick, sexual contact should stop and resume only after diarrhea symptoms have ceased for at least two weeks. Health authorities on both sides of the Atlantic are working to better understand the resistant strains and develop new tools to slow their spread. Until then, the disease will likely continue surfacing in headlines whenever diarrheal illness appears in the news—not because of a current outbreak, but because the underlying problem has become harder to solve.