Should we be afraid of dermatophilosis, also called “mud itch”? According to a study by the European Union Health Agency (ECDC) published Wednesday June 17, France, Germany, Spain and Sweden reported 70 cases of skin infections caused by this bacteria, most of them diagnosed between December 2025 and June 2026.
For the first time, “this suggests a possible change in the dynamics of transmission, with human-to-human transmission through close physical contact being the most likely route” to explain this string of cases, details the ECDC. However, “indirect transmission through contaminated surfaces and objects cannot be excluded at this stage,” adds the organization.
In France, around forty cases of this disease – more common in tropical areas – had been identified as of June 1, 2026, notably in Paris, Grenoble, Saint-Étienne and especially in Lyon. It all started with the report of the discovery of an “atypical bacteria”, in certain patients following preventive treatment for HIV, who presented pustules and crusts on the genitals, beard or torso. Generally not very painful, these lesions are sometimes accompanied by itching.
Analyzes showed that they were suffering from dermatophilosis, a skin disease usually contracted by livestock and domestic or wild animals, the symptoms of which are visible on their backs. The first nine patients identified in Lyon did not report any contact with animals. However, all of them had frequented saunas or meeting places.
Same context among other men also affected in Spain at the same time, followed by teams from Barcelona. Furthermore, the strains identified in the two countries suggest spread from the same source.
A bacteria that is “transmitted sexually”
“We form the hypothesis that this bacteria is transmitted sexually, (…) during close skin-to-skin contact, which would be favored by a hot and humid environment,” explains to AFP Doctor Maxime Bonjour, public health doctor at the Croix-Rousse hospital in Lyon and one of the main authors of a study on the subject published in the June issue of the journal Emerging Infectious Diseases (EID).
This disease “is very easily treated, with antibiotics and local care”, he adds, advising when symptoms appear to consult a Cegidd center (Free information center for screening and diagnosis of infections by the human immunodeficiency virus and viral hepatitis and sexually transmitted infections).
Until now, this infection in humans had only been reported sporadically. Before the series of recently identified cases, only certain professions (farmers, veterinarians, horse riders) had developed it very exceptionally – barely 12 scientific articles sometimes mentioning several cases have been written since 1974.
“The overall risk for the population is considered very low, given the very low probability of infection by D. congolensis and its very limited impact due to the benign clinical course of the disease,” reassures the European health agency.
For scientists, this change in the transmission dynamics of “mud itch” is a further manifestation of the “One Health” concept, according to which animal, human and environmental health are interconnected.
