Orf virus infection

Abstract

Orf virus (ORFV) is an important pathogen responsible for a highly contagious zoonotic viral infection that threatens those who handle sheep and goats. Orf virus is the prototype of the Parapoxvirus genus, and its resilience in the environment and ability to reinfect its host has contributed to the spread and maintenance of the infection in many species. In healthy humans, the disease usually resolves spontaneously within 3 to 6 weeks. There is no specific treatment and many different approaches such as use of imiquimod, cidofovir, curettage, shave excision, cryotherapy, and electrocautery have all been reported to be successful, without supporting evidence from controlled clinical trials. Throughout its interaction with the different hosts, ORFV has evolved a strategy for immune evasion via the development of an array of virulence factors. The interaction of ORFV with the immune system has been the subject of research for decades. Whole inactivated ORFV has been used as a type of immunomodulating drug; a so called paramunity inducer proposed as both a preventative and a therapeutic immunomodulator across various species. Additional research on the remarkable strategies underlying ORFV infection could lead to improved understanding of skin immunity.

Keywords: ecthyma contagiosa; immunity; orf; poxvirus; virology; virulence factor.