What is TMVII? Doctors warn of fungal STI spreading among men who have sex with men

Health authorities in the United States are monitoring an emerging fungal infection that can spread during sex and cause persistent skin lesions, with a growing cluster of cases reported in the Midwest.

The infection is caused by Trichophyton mentagrophytes type VII (TMVII), a dermatophyte fungus linked to a sexually transmitted form of ringworm. It produces inflamed, itchy lesions that can appear on the genitals, buttocks, face, trunk, arms or legs. 

Health officials say the infection spreads through direct skin-to-skin contact, including during sexual activity, and fungal spores may also transfer through contaminated items such as towels or bedding. 

What are symptoms of TMVII?

Symptoms typically resemble ringworm, with circular, red and scaly rashes that may be painful or itchy. Because the condition can resemble eczema or psoriasis, patients sometimes delay seeking treatment. 

TMVII was first identified in June 2024 after a man in New York City developed genital lesions following travel to several locations in Europe and to California. During the trip he had sexual contact with multiple male partners. 

Since then, public health agencies have reported additional cases. Officials in Minnesota say the state is currently experiencing the largest known outbreak of the infection in the United States, with more than 30 confirmed or suspected cases reported since mid-2025. 

How is TMVII treated?

Researchers say infections have disproportionately affected men who have sex with men, although the fungus can spread through any close skin contact with an infected person. 

Treatment usually involves oral antifungal medication and can take several weeks. In some cases, therapy may continue for up to 12 weeks before the rash fully resolves. 

Health agencies advise people to seek medical advice if they develop unexplained rashes, particularly around the genitals or buttocks. Patients diagnosed with TMVII are typically advised to avoid skin-to-skin contact, inform sexual partners and wash clothing or bedding at high temperatures to reduce the risk of transmission.