Arbovirus of marine mammals: a new alphavirus isolated from the elephant seal louse, Lepidophthirus macrorhini

A novel alphavirus was isolated from the louse Lepidophthirus macrorhini, c ollected from southern elephant seals, Mirounga leonina, on Macquarie Islan d, Australia. The virus displayed classic alphavirus ultrastructure and app eared to be serologically different from known Australasian alphaviruses. N early all Macquarie Island elephant seals tested had neutralizing antibodie s against the virus, but no virus-associated pathology has been identified, Antarctic Division personnel who have worked extensively with elephant sea ls showed no serological evidence of exposure to the virus. Sequence analys is illustrated that the southern elephant seal (SES) virus segregates,vith the Semliki Forest group of Australasian alphaviruses. Phylogenetic analysi s of known alphaviruses suggests that alphaviruses might be grouped accordi ng to their enzootic vertebrate host class, The SES virus represents the fi rst arbovirus of marine mammals and illustrates that alphaviruses can inhab it Antarctica and that alphaviruses can be transmitted by lice.