Since, health authorities in Europe have been monitoring an unusual outbreak of dermatophilosisa bacterial skin infection typically found in animals. The recent cases, however, have been identified in men who have sex with men (MSM)raising concerns about human-to-human transmission. This development has drawn comparisons to the mpox (monkeypox) outbreak of summer 2026, although experts emphasize that the two infections are distinct in their severity and transmission patterns.
The infection, sometimes referred to as “mud fever” in veterinary circles, is caused by the bacterium Dermatophilus congolensis. While it primarily affects animals like cattle and horses, recent data suggests it can spread between humans through close skin-to-skin contact. The European Centre for Disease Prevention and Control (ECDC) reported nearly 100 cases across Europe by the end of 2026, with a significant cluster in France and Spain.
Transmission and Risk Factors
The ECDC’s report, published on June 17, 2026, highlights that many of the affected individuals had visited saunas in the days leading up to their symptoms. This pattern mirrors the early stages of the mpox outbreak, which also saw clusters in saunas and other venues frequented by MSM. However, the ECDC stresses that dermatophilosis is not inherently a “sauna disease” but rather thrives in warm, humid environments where close contact is common.
Dr. Maxime Bonjoura public health physician who identified some of the first cases in Lyon, notes that the infection is spread through direct skin contact rather than bodily fluids. “This is a dermatological sexually transmitted infection (STI) transmitted by skin-to-skin contact,” he explains. As a result, condoms do not provide effective protection against dermatophilosis. The ECDC also notes that while transmission via contaminated surfaces (such as shared towels) is possible, this has not been definitively proven.
Symptoms and Diagnosis
The infection presents as skin lesionsincluding crusts, pustules, or papules, typically appearing a few days after exposure. These lesions are most commonly found on the genital area, pubis, testicles, or anusbut can also appear on the torso, arms, or inner thighs. While the lesions may itch, they are generally not painful and do not leave scars. Importantly, the infection appears to be mild and easily treatablewith no severe cases reported to date.
Dr. Bonjour emphasizes that the infection does not typically cause systemic symptoms, such as fever or fatigue. However, individuals with compromised immune systemsincluding those living with HIV, should monitor for symptoms closely, as data on their risk remains limited. If symptoms appear, Dr. Bonjour recommends consulting a CeGIDD (Centre Gratuit d’Information, de Dépistage et de Diagnostic) or a sexual health clinic for testing and treatment.
Treatment and Prevention
Dermatophilosis responds well to antibioticswith amoxicillin being a commonly prescribed treatment. In some cases, topical antiseptics alone may be sufficient to clear the infection. The ECDC reports several instances of spontaneous recovery without medical intervention. To prevent transmission, health authorities recommend basic hygiene practicessuch as avoiding close contact with individuals displaying suspicious skin lesions, not sharing personal items like towels, and regularly washing hands and affected areas with soap and water.
Despite the rise in cases, experts urge caution against overreaction. “We are not facing a scenario comparable to mpox in 2026,” Dr. Bonjour reassures. “This is a mild skin infection that is easily treatable and does not pose a significant public health risk at this stage.” The ECDC agrees, stating that while the infection warrants monitoring, there is no evidence of widespread transmission or severe outcomes.
As research continues, health authorities will likely provide further guidance on managing and preventing dermatophilosis. For now, staying informed and practicing good hygiene remain the best defenses against this emerging infection.
