This negative-stained transmission electron micrograph (TEM) image depicted the ultrastructural details of an Orf virus, a member of the genus Parapoxvirus. Note the spiral arrangement of the external tubular ridges on the ovoid-shaped virus particle, or virion. The criss-cross pattern is an artefact caused by superimposition of images of top and bottom surfaces of the virion.

The orf virus is a pathogen common to sheep and goats, but can at times be transmitted to humans, in which case the virus is known as being “zoonotic”. When a human being becomes infected, the symptoms are mainly confined to the skin, and consist of “weeping” nodules manifesting upon the dorsum, or back of the hands, and which heal in approximately thirty-five days in a spontaneous fashion.

Photo credit: Cynthia Goldsmith

Source:CDC's Public Health Image Library Image #8434

Cette image est l’œuvre des Centers for Disease Control and Prevention , division du Département de la Santé et des Services Sociaux des États-Unis, réalisée par un employé dans le cadre de ses activités professionnelles. En tant qu'œuvre du gouvernement fédéral des États-Unis d'Amérique, cette image est placée dans le domaine public. eesti ∙ Deutsch ∙ čeština ∙ español ∙ português ∙ English ∙ français ∙ Nederlands ∙ polski ∙ slovenščina ∙ suomi ∙ македонски ∙ українська ∙ 日本語 ∙ 中文（简体）‎ ∙ 中文（繁體）‎ ∙ العربية ∙ +/−