Editorial Keeping an Eye on Poxviruses

and Hygiene, MacNeil and others describe the use of serologic methods to aid in retrospectively identifying a pustular rash illness that occurred among residents of a group of villages in the Republic of the Congo in 2007. 1 On the basis of descrip-tions of the skin lesions, there were two major candidates for the diagnosis. The first candidiate was chickenpox, which is caused by a highly contagious human-adapted herpesvirus, and is endemic in central Africa, where immunization rates are low. The second candidiate was monkeypox, a zoonosis caused by an orthopoxvirus maintained in local rodents, which usu-ally occurs as single cases, but can also produce short chains of person-to-person transmission. Although monkeypox has been observed with increasing frequency in the neighboring Democratic Republic of the Congo over the past four decades, it has only been reporte