Orf: an update on current research and future perspectives.

Orf is one of the most widespread viral diseases around the world affecting mostly, small ruminants and sometimes, other species including wild animals. Of late, there have been an increasing number of reports of new species being affected by the disease, implying a dynamic host-pathogen interaction. The causative agent, orf virus, has been extensively investigated over recent years because of its zoonotic importance and growing host-range. The evasive mechanisms that the virus has developed to adapt and grow in the presence of an active immune response helps to explain the ability of the virus to repeatedly re-infect the same host.. Exposure of animals to stress or immunosupression as a result of therapy or primary viral infection can accentuate the severity of the disease. Genes homologous to host cytokines or their antagonists and that contribute to viral virulence have been found in the viral genome. A combination of electron microscopy, histology and polymerase chain reaction is the most accurate laboratory approach for confirmation of the disease although clinical signs are often typical. However, some infections may be confounded by similar clinical manifestations caused by other infections. The review presents, in brief, a recent understanding on the virus pathobiology, zoonotic significance, including novel approaches to disease management in field conditions.