A doctor has opened up about the horrifying symptoms he experienced after he caught sexually transmitted diarrhea that's "close to untreatable".

Dr. Carlton Thomas, a gastroenterologist and host of the Butt Honestly podcast, became seriously ill after a sexual encounter at a gay bar in Fort Lauderdale, Florida, last year, The Advocate reported.

Thomas shared that he engaged in oral sex inside the venue’s dark room play space, but it wasn't until several days after returning home that his health deteriorated.

He had developed diarrhea, dehydration, extreme fatigue, and a fever that reached 104 degrees Fahrenheit.

A doctor has opened up about the horrifying symptoms he experienced after he caught sexually transmitted diarrhea. Credit: Kinga Krzeminska / Getty

The doctor suspected that he had Shigella, a highly-contagious bacteria infect that affects roughly half a million people in the United States each year. It can spread through contaminated food, feces, water, unwashed hands, and certain types of sexual contact.

Thomas' condition became worse when he began having bloody diarrhea, eventually needing IV fluid bags to treat his dehydration.

Doctors also treated him with the antibiotic azithromycin, and his symptoms improved over the next 24 hours.

"I was very lucky," he said. "It felt like I was going to die."

Although Thomas has now recovered, the frightening ordeal has motivated him to raise awareness about the infection.

Thomas' condition became worse when he began having bloody diarrhea, eventually requiring IV fluid bags to treat his dehydration. Credit: SDI Productions / Getty

Spreading through sex

The infection triggers gastrointestinal symptoms such as stomach pain, cramps, fever, vomiting, and diarrhea containing blood or mucus.

While most people recover within approximately a week, Shigella can become life-threatening by dehydrating the body, causing septic shock, neurological complications, or internal bleeding.

Researchers are increasingly concerned about infections spreading through sexual contact, particularly among gay, bisexual, and other men who have sex with men.

Activities involving contact between the mouth and anus can transmit the bacteria, either directly or indirectly.

Dr. Demetre C. Daskalakis, Chief Medical Officer at Callen-Lorde Community Health Center and former CDC chief vaccine officer, said higher reported infection rates among queer men reflect multiple factors.

"We see higher reporting among men who have sex with men largely because certain sexual networks include sexual activities, like rimming, that can facilitate fecal–oral exposure," he said.

"Men who have sex with men are also more likely to be tested for bacteria and parasites that cause diarrhea and counted among cases."

However, as with many illnesses that have disproportionately affected queer people, this data tells only part of the story.

"What's missing is underdiagnosis in other populations, lack of routine testing, and stigma that keeps people from seeking care," he continues. "Disease surveillance data often reflects access and trust in healthcare as well as the likelihood of medical providers to order the tests that diagnose Shigella."

Scientists warn infection is becoming ‘close to untreatable’

The growing threat extends beyond the way Shigella spreads, as research published in July 2026 revealed that sexually transmitted variants of the bacteria in the UK spread 15% faster than infections associated with travel, food, or nursery outbreaks.

Scientists believe sexual transmission may now be a major route of infection within certain communities, although inconsistent questioning about sexual history makes the true scale difficult to establish.

Cambridge geneticist Kate Baker, a lead author on the July study, warned that many people are unaware of the risks.

"Many men who have sex with men are unaware of the serious and increasing risk posed by sexually transmitted Shigella," she said.

The Centers for Disease Control and Prevention (CDC) also highlighted the increasing prevalence of drug-resistant Shigella in the United States.

Researchers found that the proportion of tested bacterial samples classified as extensively drug-resistant rose from 0% in 2011 to 8.5% in 2023, with the majority of identified cases affecting adult men.

Most of these resistant cases have affected adult men, with patients contracting the strain through sex, requiring an average hospital stay of four to five days.

"This disease has gone from being relatively treatable with off-the-shelf drugs to being close to untreatable over the course of the last decade or so," Baker said.

Speaking to Science Alert, she added: "This isn't just one form of sexually transmissible diarrhea. This is multiple overlapping variants emerging that are all quickly becoming resistant to the drugs we use to treat them."

"It's highly likely that if you contracted your Shigella through sex, you require different treatment to someone who contracted it through travel."

The best way to protect yourself from Shigella is by preventing transmission.

Recommended precautions include washing your hands, genitals, and anus with soap and water before and after sexual activity, as well as cleaning sex toys thoroughly.

Experts also state that using protective barrier methods like condoms and dental dams can lower risk.

In addition to this, the California Department of Public Health issued a direct warning: "Don't have sex with someone who has had diarrhea in the last two weeks."

Featured image credit: Kinga Krzeminska / Getty

A bacterial illness historically linked to poor sanitation is now finding new avenues of transmission.

Shigella bacteria infect roughly half a million people in the United States each year, triggering gastrointestinal symptoms such as stomach pain, cramps, fever, vomiting, and diarrhea containing blood or mucus, which is the hallmark of dysentery.

Beyond causing severe physical discomfort, the infection can become life-threatening by dehydrating the body, causing septic shock, neurological complications, or internal bleeding.

Historically, children under five years old, travelers to areas with lower sanitation standards, and individuals experiencing homelessness faced the highest risk of contracting the bacteria.

Transmission typically occurs when infected fecal matter enters the mouth via unwashed hands or contaminated food and water. Remarkably, as few as 10 organisms are enough to make a person ill.

Health experts are warning against having sex with someone who has had diarrhea in the last two weeks. Credit: Westend61/Getty

However, medical researchers have noticed a shift in how the disease moves through the population. Emerging data shows that sexual contact is increasingly driving infections, creating new public health challenges.

Spreading through sex

The population currently seeing one of the fastest increases in Shigella infections includes gay, bisexual, and other men who have sex with men.

Experts describe the bacteria as endemic within these communities, meaning it maintains a constant presence. A July study indicated that the spread of the disease through sex grew 15% faster year over year between 2015 and 2020 compared to transmission through travel, food, or nursery outbreaks.

Some researchers suggest that sexual contact may now represent the primary transmission route, though incomplete intake questioning at clinics makes precise tracking difficult.

A widespread lack of awareness regarding these transmission pathways continues to fuel new cases.

"Many men who have sex with men are unaware of the serious and increasing risk posed by sexually transmitted Shigella," said Cambridge geneticist Kate Baker, a lead author on the July study.

Emerging data shows that sexual contact is increasingly driving infections. Credit: Oleksandr Sharkov / Getty

Becoming a superbug

Compounding the problem of rapid transmission is the rise of antibiotic resistance. According to the Centers for Disease Control and Prevention (CDC), drug-resistant strains of the infection rose from 0% in 2011 to 8.5% in 2023.

Most of these resistant cases have affected adult men, with patients contracting the strain through sex requiring an average hospital stay of four to five days.

"This disease has gone from being relatively treatable with off-the-shelf drugs to being close to untreatable over the course of the last decade or so," Baker said.

Experts suspect that bystander resistance may be contributing to the problem. This occurs when an inappropriate antibiotic is prescribed for a pathogen, failing to kill the target while granting the bacteria an opportunity to adapt.

"This isn't just one form of sexually transmissible diarrhea," Baker told Science Alert. "This is multiple overlapping variants emerging that are all quickly becoming resistant to the drugs we use to treat them. It's highly likely that if you contracted your Shigella through sex, you require different treatment to someone who contracted it through travel."

Treating and preventing Shigella

While mild cases often resolve within a week using rest and fluids, severe cases traditionally rely on antibiotics to shorten the illness and reduce contagiousness.

Because growing drug resistance makes standard treatments less reliable, health officials emphasize preventative hygiene measures.

Recommended precautions include washing hands, genitals, and the anus with soap and water before and after sexual activity, as well as cleaning sex toys thoroughly.

Using barrier methods like condoms and dental dams can also lower risk. Additionally, public health guidance from the California Department of Public Health offers a straightforward rule: "Don't have sex with someone who has had diarrhea in the last two weeks."

Featured image credit: Westend61/Getty