A STI Fungus Is Making Itself Cozy in the US

A sexually transmitted form of roundworm is making a gross splash in the United States. Health officials in Minnesota are warning doctors and the public about an outbreak of the emerging fungus Trichophyton mentagrophytes genotype VII, also known as TMVII.

The Minnesota Department of Health says there have been dozens of confirmed or suspected TMVII cases seen in the Twin Cities metro area since last summer. It appears to be the largest outbreak of TMVII in the U.S. recorded so far. Doctors in the area are being told to report cases to the health department, while people worried about having it should seek medical care and take precautions with their sexual partners.

“Patients concerned they might have a rash consistent with TMVII, particularly if they have had recent sexual contact with others with a rash, should visit an STI clinic for evaluation and treatment,” the Minnesota Health Department said in a statement shared with Gizmodo on Thursday.

A growing fungal menace

Despite the name, ringworm (or tinea) is actually caused by various species of fungi, not a wormy parasite. It’s the broad term for a distinctive type of skin fungal infection, one that leaves behind a circular rash. Ringworm can be further distinguished by where on the skin this infection happens; ringworm around the feet, for instance, is often known as athlete’s foot.

Ringworm is usually easily treatable with antifungals and is more of an annoyance than a serious health concern. But there have been several emerging kinds of ringworm that have alarmed researchers and health officials in recent years, one of which is TMVII. Researchers first discovered TMVII in parts of Europe and Asia several years ago. In June 2024, doctors in New York City reported the first U.S. cases, and there have been scattered reports in other major cities since.

Unlike most ringworm-causing fungi, TMVII appears to spread predominantly through close sexual contact. So far, these cases have primarily been seen in men who have sex with men. TMVII also seems more likely to cause highly inflammatory, painful, and persistent rashes that can lead to permanent scarring; these severe cases are then at higher risk of other complications, including secondary infections that have to be treated with antibiotics.

Minnesota’s first known case of TMVII was reported to the health department in July 2025, involving a resident who developed a rash around their genitals. Following this and other reports, health officials established an expanded surveillance system to better identify cases. As of Feb. 12, there have been 13 confirmed and 27 suspected cases of TMVII, health officials told Gizmodo.

It seems to be the largest cluster of TMVII reported in the U.S. to date, though officials note that doctors aren’t required to report cases to their local health department, meaning that most areas don’t have good surveillance data. TMVII can also be hard to diagnose, especially since the rashes can be confused for other skin conditions like eczema or psoriasis.

“Overall risk to the public is low, however men who have sex with men, persons using anonymous apps, and persons with a history of previous STI infections may be at higher risk,” the department said.

What to do about TMVII

On the positive side, TMVII does still appear to be readily treatable with antifungals, unlike some other emerging forms of ringworm. But cases have tended to require prolonged treatment to eradicate the infection.

According to the Minnesota Department of Health, seeking treatment early for TMVII can reduce the risk of worsening illness. So people with possible symptoms, such as itchy, scaly, coin-shaped rashes on their buttocks, genitals, extremities, trunk and/or face, should see a doctor, as well as notify their sexual partners to seek care, too.

In terms of prevention, officials recommend that people avoid skin-to-skin contact, including sexual contact, if they or their partners develop a new rash. Additionally, those confirmed or suspected to have TMVII should cover their rashes with bandages or clothing, and avoid sharing personal items such as towels, bedding, and razors. And they should wash their hands thoroughly after touching TMVII-affected areas to reduce the risk of the fungus spreading elsewhere along the body.