Paris, Lyon, May 28, 2026 – A new sexually transmitted infection (STI), previously known to affect cattle and horses in tropical climates, has been detected in humans, causing concern among medical professionals. Nine cases have been reported across Europe, with several identified in Paris and Lyon, according to a laboratory statement.
Origin and Transmission of the New STI
The infection is caused by the bacterium Dermatophilus congolensis, which typically infects animals such as horses, goats, and cows in tropical and subtropical regions. Human cases have historically been rare and linked to direct contact with contaminated animals. However, recent cases in humans have shown no such animal contact or travel to tropical areas.
Researchers at Vall d’Hebron University Hospital in Barcelona first raised the alarm after identifying nine cases in Catalonia. The infection appears to be spreading across Europe, with confirmed cases now in France.
Mutation and Human-to-Human Transmission
Laboratory analyses indicate that the bacterium has mutated, allowing for human-to-human transmission. This shift from a zoonotic (animal-borne) infection to a human one is puzzling researchers, who suggest globalization and climate change could be contributing factors to this genetic evolution.
Notably, the recently detected human cases involve men who have had sex with other men, with several patients having frequented saunas and other humid environments prior to the onset of symptoms. This suggests that sexual contact and close skin-to-skin contact, especially in warm and moist conditions, are conducive to the bacterium’s transmission.
Symptoms and Treatment
The symptoms of this new STI manifest as skin lesions resembling small pimples (papules, pustules, vesicles) filled with pus, as described in a study published by researchers in Emerging Infectious Diseases. These lesions eventually rupture, forming a yellowish or brownish crust.
Commonly affected areas include the genitals, anal region, groin, and beard. While highly contagious, the good news is that all reported patients have recovered with antibiotic treatment, and no severe complications have been noted so far.
Public Health Recommendations
In response to this emerging STI, health authorities are reiterating the importance of using condoms during sexual intercourse. Individuals who experience any of the aforementioned symptoms in the affected areas are urged to consult their doctor promptly or visit a screening center.
Treatment typically involves antibiotics and an antiseptic to limit bacterial proliferation and promote the healing of skin lesions. The available treatments are highly effective, leading to a complete and rapid recovery.
While the situation is being closely monitored, medical experts emphasize that there is no need for panic. The focus remains on early detection, appropriate treatment, and continued research into the bacterium’s mutation and spread.
Authorities continue to investigate the exact mechanisms of transmission and the broader implications of this new development for public health.
