A bacterial infection typically caught from livestock may have become a sexually transmitted disease among humans, according to French epidemiologists.
Dermatophilosis, commonly called "mud fever," is a zoonosis rarely seen in people. Historically, cases were limited to farmers and riders handling infected horses or cattle.
Writing in the US journal Emerging Infectious Diseases, researchers from the Hospices Civils de Lyon detailed a cluster of roughly forty cases in France and Spain between January and June. The study focused on nine patients in Lyon. Seven reported visiting gay saunas there, sometimes the same venues, days before lesions appeared.
The research team found no direct links between patients but concluded that genomic similarity and shared sexual exposures strongly suggest human-to-human transmission.
Symptoms include pustules and crusts on the skin, concentrated around the genital area, torso, mouth, and lower limbs. No patients required hospitalization. An antibiotic regimen, occasionally combined with topical antiseptic care, led to rapid recovery.
Scientists believe the heat and humidity of sauna environments likely facilitated transmission by promoting the release of zoospores-mobile bacteria capable of penetrating the skin through direct contact.