Human orf.

Human orf is usually considered a rare disease caused by a virus belonging to the paravaccinia subgroup of pox viruses and transmitted to man from sheep and goats. This paper presents 119 new human cases with epidemiological, clinical, histopathological and ultrastructural findings. Erythema multiforme was found to be a common complication of human orf. Other complications tended to be caused by overtreatment. Electron microscopy of negatively stained suspensions from lesions was found to be the best and most rapid diagnostic method available.