New Sexually Transmitted Infection Detected in Paris and Lyon: Animal-Origin Bacterium Raises Public Health Concerns
Paris, May 28, 2026 – Health authorities are expressing concern following the detection of a new sexually transmitted infection (STI), previously known to affect cattle and horses, with several cases reported in Paris and Lyon. This emergent health issue highlights a potential shift in zoonotic diseases, as the bacterium responsible, Dermatophilus congolensis, appears to have mutated, enabling human-to-human sexual transmission.
Nine Cases Identified Across Europe, Including France
The alarm was initially raised by teams at Vall d’Hebron University Hospital in Barcelona, after identifying nine cases in Catalonia. The infection has since been reported in other European cities, with a laboratory statement confirming multiple cases in Paris and Lyon, France. This development marks a significant concern for public health officials across the continent.
From Animal to Human: A Mutated Bacterium
The bacterium Dermatophilus congolensis is well-known in veterinary medicine, typically causing skin infections in animals such as horses, goats, and cows in tropical and subtropical regions. Human cases have traditionally been rare and linked to direct contact with infected animals.
However, recent human cases in Europe present a puzzling anomaly: none of the affected patients had contact with animals or traveled to tropical zones. Instead, these cases predominantly involve men who have sex with men, with several individuals having frequented saunas and other humid environments prior to the onset of symptoms. This suggests a novel transmission pathway.
Bacterium Undergoing Mutation: Globalization and Climate Change as Potential Factors
Laboratory analyses indicate that the bacterium has undergone a mutation, allowing it to infect humans and be transmitted sexually. Researchers are investigating whether factors such as globalization or climate change could be contributing to this genetic evolution, transforming what was once an exclusively zoonotic infection into a human one.
Symptoms and Treatment: What You Need to Know
Despite the concerning nature of this new development, there is no immediate cause for panic. All reported patients have recovered with antibiotic treatment, and no severe complications have been noted. The symptoms typically manifest as skin lesions resembling small pimples (papules, pustules, vesicles) filled with pus, as detailed in a study published by researchers in Emerging Infectious Diseases. These lesions eventually rupture and form yellowish or brownish crusts.
Commonly affected areas include the genitals, anal region, groin, and beard. The infection is highly contagious and spreads through sexual contact or close skin-to-skin contact. Warm and humid conditions are particularly conducive to bacterial transmission.
Public Health Recommendations: Prevention and Early Detection
In response to this new sexually transmitted infection, health authorities are reiterating the importance of using condoms during sexual intercourse. Individuals who notice the aforementioned symptoms in the affected areas are advised to consult a doctor immediately or visit a screening center. Treatment typically involves a course of antibiotics and an antiseptic to control bacterial proliferation and promote the healing of skin lesions. Available treatments are highly effective, leading to a complete and rapid recovery.
