An outbreak of a highly contagious fungus, known for causing severe red rashes on the genitals, is spreading rapidly in Minnesota, marking what officials describe as the largest such outbreak in the United States.

Health authorities in the state have identified 40 confirmed or suspected cases of ringworm, a skin infection transmitted through direct contact. This infection results in distinct, coin-shaped rashes appearing on areas such as the buttocks, trunk, arms, and legs.

The culprit behind these infections is a new strain of the ringworm fungus, identified as Trichophyton mentagrophytes genotype VII (TMVII). This strain is notorious for causing painful, persistent rashes that may lead to scarring.

According to the Centers for Disease Control and Prevention (CDC), this strain predominantly affects men who have sex with men, due to the fungus’s spread within these sexual networks.

All reported cases have emerged in the past seven months within the Twin Cities metropolitan area, encompassing Minneapolis and Saint Paul, as noted by health officials. The outbreak was first detected in July 2025 when a resident of the Twin Cities sought medical attention for a genital rash.

While no fatalities have been linked to this infection, doctors caution that it is highly contagious. Individuals with weakened immune systems may find it particularly challenging to overcome the infection.

Officials revealed the outbreak on Wednesday in a health alert, and are urging anyone who has symptoms of the infection to contact their doctor immediately. Physicians are being urged to treat patients immediately rather than wait for confirmatory testing before offering them prescription medications to reduce the spread of the disease.

The Minnesota Department of Health believes this is the ‘largest known outbreak’ of TMVII in the US since the fungus was first detected in New York in 2024.

Officials in Minnesota are warning about the nation’s largest ever outbreak of Trichophyton mentagrophytes genotype VII (TMVII) (stock photo)

Despite its name, ringworm is not caused by a worm but by a fungus that is closely related to the disease behind athlete’s foot and jock itch.

It is spread via direct skin-to-skin contact with infected areas and fungal spores that may spread from infected skin to razors, sex toys and linens.

Patients suffer symptoms within four to 14 days of infection. In TMVII infections, rashes may also have bumps or pimples, and can be mistaken for other conditions such as eczema or psoriasis.

To treat the infection, patients may be prescribed antifungal lotions or tablets to help clear the infection. There is no vaccine against the disease.

In cases of TMVII, individuals may also receive antibiotics because the strain can cause a worsening bacterial infection. 

In mild cases, ringworm can be cleared in two to four weeks. In more serious cases, however, it can take six to 12 weeks to resolve. 

According to officials in Minnesota, of the infections, 13 cases have been confirmed and 27 are suspected, reports infectious diseases website CIDRAP based on an official document it said was shared with reporters.

In its alert, the department said: ‘More than 30 confirmed or suspected cases have been reported in the metro area, resulting in the largest known outbreak of [ringworm] in the United States.’

Ringworm can be spread sexually and via skin-to-skin contact (stock image)

Minnesota Department of Health officials told Daily Mail that there was no link between the cases and migrants in the area.

TMVII was first detected in the US in 2024 in a man who had sex with men and had returned to New York City from a recent trip to Europe.

Since then, the CDC has detected sporadic cases among men who have sex with men, primarily in larger cities in the US. Normally, there are no more than a handful of cases.

The strain TMVII is rare, but is most likely to be detected in Southeast Asia and Europe, particularly among men who have sex with men.

It was first reported in 2017 in travelers who had returned to Switzerland from Thailand. Since then, cases have emerged in a number of neighboring countries including France.

Online, the Minnesota Department of Health says that fungal spores can be killed with common disinfectants such as diluted chlorine bleach. It says potentially infected linens should be laundered on high heat.

It recommends that those with new rashes should cover them with bandages or clothing to minimize unintentional infection or spread.

To prevent an infection, people in Minnesota are being advised to avoid skin-to-skin contact if they or their partner has a new rash.

Individuals are also being advised to consider pausing or limiting sexual activity if there are individuals in their network who have recently reported a new rash. 

Those who have a new rash are being advised to inform sexual partners and to consider covering the rash with bandages or clothing to minimize the risk of unintentional spread.

They are being urged to contact their doctor immediately.