ISOLATION OF CALICIVIRUSES FROM SKUNKS THAT ARE ANTIGENICALLY AND GENOTYPICALLY RELATED TO SAN-MIGUEL-SEA-LION-VIRUS

Caliciviruses were isolated from feces of skunks imported from the nor th central United States to Canada. Virus isolation was accomplished u sing adenovirus-transformed human kidney (293) cells, swine testes and Vero cells. Plaque size variants were present, but there was no appar ent difference in virus morphology by negative stain or immune electro n microscopy. Pigs infected with skunk calicivirus had a slightly elev ated body temperature at 3 days postinfection. Although the infected a nimals seroconverted, no overt clinical signs were observed. Purified infectious genomic skunk calicivirus RNA behaved exactly as San Miguel sea lion virus (SMSV) 1 and 4 genomic RNA in cell culture transfectio n studies. Of the cell types examined, only primary porcine kidney, 29 3 and Vero cells supported viral replication. No viral replication was detected in cells of bovine, equine, ovine, caprine or feline origin. The skunk caliciviruses contained a single capsid protein with a rela tive mobility similar to SMSV virus 1 and 4 capsid proteins. The capsi d protein was positive by Western blot analysis with SMSV and vesicula r exanthema of swine virus (VESV) antisera. Purified RNA from skunk ca licivirus infected cells was subjected to reverse transcription follow ed by polymerase chain reaction. Nucleotide sequences were identified that had greater than 85% similarity to the 2C and RNA polymerase gene regions of SMSV 1 and 4 and VESV A48. Predicted amino acid sequences of these regions were greater than 95% similar and the partial coding sequence of the polymerase gene contained the YGDD sequence common to positive-strand RNA virus polymerases.