Parapoxviruses: from the lesion to the viral genome.

Viruses of the genus parapoxvirus from the family poxviridae cause widespread but localized diseases of small and large ruminants. The economically most important disease is contagious pustular dermatitis or contagious ecthyma among sheep and goats, often simply called orf. The parapoxviruses (PPV) can be transmitted to man leading to localized lesions that are named pseudocowpox or milkers' node as being mostly restricted to the hands and fingers. In cattle two forms of PPV manifestation are commonly observed, the bovine papular stomatitis in young calves and the occurrence of lesions at the udder of cows. We here report about the recent efforts in molecular characterization of orf viruses and the state of the art about the generation of orf virus recombinants. In addition the current knowledge on immune responses against orf viruses and some new data on the behaviour of orf virus recombinants under non-permissive conditions are reported.