A type of sexually transmitted roundworm is making a big splash in the United States. Minnesota health officials are CAUTIONS doctors and the public about an outbreak of emerging fungus Trichophyton mentagrophytes is a species of flowering plant genotype VII, also known as TMVII.

The Minnesota Department of Health says there have been several confirmed or suspected cases of TMVII seen in the Twin Cities metro area since last summer. This appears to be the largest TMVII outbreak in the US on record to date. Doctors in the area have been told to report cases to the health department, while people who are concerned about it should seek medical attention and be careful with their sexual partners.

“Patients who are concerned that they have a rash consistent with TMVII, especially if they have had recent intercourse with someone who has 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 threat

Despite the name, ringworm (or tinea) is caused by a variety of fungi, not a wormy parasite. This is the broad term for a different type of fungal skin infection, one that leaves a circular rash. Eczema can be more pronounced where on the skin this infection occurs; Ringworm around the feet, for example, is often known as athlete’s foot.

Eczema is usually easily treated with antifungals and is more of an annoyance than a serious health concern. But there are some emerging types 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 cases in the US, and there have been scattered reports in other major cities since then.

Unlike most fungi that cause ringworm, TVMII appears to be spread mostly through intimate sex. Currently, these cases are primarily seen in men who have sex with men. It seems like TVMII too more likely causes extremely inflammatory, painful, and persistent rashes that can lead to permanent scarring; These severe cases have a higher risk of other complications, including secondary infections that must be treated with antibiotics.

The first known case of TMVII in Minnesota was reported to the health department in July 2025, involving a resident with a rash on their genitals. After these and other reports, health officials established an expanded surveillance system to better identify cases. As of February 12, there were 13 confirmed and 27 suspected cases of TMVII, health officials told Gizmodo.

It appears to be the largest cluster of TMVII reported in the US to date, although officials note that doctors are not required to report cases to their local health department, meaning most areas do not have good monitoring data. TMVII can also be difficult to diagnose, especially since the rashes can be confused for other skin conditions such as eczema or psoriasis.

“The overall risk to the public is low, although men who have sex with men, people who use anonymous apps, and people with a history of past STI infections may be at higher risk,” the department said.

What to do about TMVII

On the positive side, TMVII still appears to be easily treated with antifungals, unlike others. emerged ringworm forms. But cases may require long-term treatment to clear the infection.

According to the Minnesota Department of Health, seeking early treatment for TMVII can reduce the risk of the disease worsening. That’s why 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 inform their sexual partners to be treated as well.

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