Cowpox Virus Infection in Pet Rat Owners—Not Always Immediately Recognized: Human to Human Transmission Is Possible in Orthopoxviruses

Abstract

I wish to congratulate the authors for their clear and well structured case reports and their detailed photographs. This publication will enable more rapid diagnosis of further cases (1). In the meantime, Campe et al have published an article in Emerging Infectious Diseases about the transmission of cowpox from rats to humans in the Munich area (2). Human to human transmission has been described for orthopoxviruses. In 2007, Zafar et al reported nosocomial infections with buffalopox viruses in burns wards in Karachi, Pakistan; a class of virus that also belongs to the genus orthopoxvirus (3). Zafar et al observed buffalopox for 5 months in 2004–5 in 19 patients from 5 burn units. A health care worker developed an infection on a finger. In all cases, the causative strain was confirmed and typed with support from the Special Pathogens Unit at the National Institute for Communicable Diseases (NICD), Sandringham, South Africa, and the Health Protection Agency (HPA)’s Centre for Emergency Preparedness and Response in Porton Down, Salisbury, United Kingdom. The authors recommend that patients should be warned about the risk of smear (contact) infections, as it happened at least in patient No 4 (lesions on abdominal skin and eye). Identification of cowpoxviruses in the biopsy specimen from a pulmonary focus proves that pneumonia in patient 6 was caused by the virus.