Experimental infection of specific pathogen-free New Zealand white rabbitswith five strains of amyxomatous myxoma virus

Myxomatosis is a specific disease of the European rabbit (Oryctolagus cunic ulus) due to a virus belonging to the genus Leporipoxvirus. Forty-seven yea rs after its deliberate introduction into Europe, the clinical aspects and the epizootiology of myxomatosis have changed. Two forms (nodular and amyxo matous) of the disease have been identified to date. A comparative study wa s made of the clinical signs, pathogenesis and gross lesions observed in ma le specific pathogen-free New Zealand White rabbits inoculated with five st rains of amyxomatous myxoma virus. All five strains induced the characteris tic amyxomatous myxomatosis clinical syndrome with clinical signs that diff ered only in intensity. The varying clinical intensity, together with the r esults of virological examination question the virulence of at least three of the five strains. Genomic analysis confirmed that the five strains came from the Lausanne strain introduced in 1952 in France and not from an unnot iced introduction of a Californian strain of myxoma virus. No link was foun d between the amyxomatous myxoma virus strains and the SG33 vaccine strain. (C) 1999 Harcourt Publishers Ltd.