Human cowpox/catpox infection, a potentially unrecognized disease

History and admission findings: A 36-year-old woman initially noticed a red spot, about pea-sized, with a central pimple over the right eyebrow and a swollen submandibular lymph node. A pressure-sensitive, 4cm large, node developed out of this small spot, with a central, black, tightly-adhering crust bearing several varioliform vesicles around its edge. In addition to swelling of the right half of the face, the patient had a fever up to 39.5 C, general malaise, nausea and vomiting. Various antibiotics were ineffective. The woman was hospitalized with a diagnosis of facial erysipelas. She owned a cat which had developed a purulent nodule on a forepaw a few days before onset of the patient's disease. Laboratory test: ESR and CRP were moderately elevated, no leukocytosis and blood cultures were sterile. Wound smears showed colonization with Klebsiella pneumoniae and Enterobacter cloacae. Diagnosis, treatment and course: The patient's general condition improved under initially calculated antibiotic dosages, which was later adapted to the measured resistance. The black-crusted nodes became larger, however, and incision was performed on the Stn day after hospitalization, under the suspicion of fluctuation. However, no pus was removed, but there was massive inflammatory infiltration of the soft tissue. Examination of samples of skin and part of the crust revealed orthopox virus (cowpox virus). Spontaneous healing followed within 3 weeks, leaving only a small scar. Conclusions: This was a cowpox virus in the sense of a zoonosis transmitted by the cat. In Germany, now that smallpox has been eradicated, the clinical presentation of infections with the orthopox virus, which are closely related to variola virus, are too little recognized. Atopic and immunocompromised patients are at risk of a cutaneous dissemination with a more severe course of the infectious illness; even a lethal outcome has been reported in Germany.