Although human cowpox virus infection is rare nowadays, an animal reservoir of this virus still exists. The general course of cowpox virus infections is usually benign but the diagnosis is difficult and often late.An 11-year-old boy, owner of two cats, presented with an infected sacral wound lesion associated with fever and lymph nodes. The wound became necrotic and other cutaneous and mucous membrane lesions developed secondarily. Blood tests did not show hyperleukocytosis or a systemic inflammatory response. Concurrently one of the cats was examined by a veterinary because of multifocal cutaneous lesions. Evocative skin biopsy specimens from the animal and, secondarily from the patient, allowed the identification of orthopoxvirus. Evolution was slowly favourable under symptomatic treatment.Poxviruses are responsible for many animal and human diseases, the most famous of them being smallpox which today is considered eradicated. Vaccination against smallpox is no longer performed since 1977. Whether the arrest of vaccinations against smallpox may induce the apparition of other poxviruses infections or alter their clinical expression is an open question.