Analysis of the serologic relationship among San Miguel sea lion virus and vesicular exanthema of swine virus isolates. Application of the western blot assay for detection of antibodies in swine sera to these virus types.

Caliciviruses are positive-sense single-stranded RNA viruses with a single capsid protein. The serotypes of the marine mammal calicivirus, San Miguel sea lion virus (SMSV), are antigenically related to vesicular exanthema of swine virus (VESV) and are potentially hazardous to swine. Western blot assays using purified SMSV serotypes 1 and 4 were used to further examine the serologic relationship among SMSV and VESV isolates. With the exception of SMSV 8 and SMSV 12, rabbit polyclonal antisera generated against all the available SMSV and VESV isolates reacted positively, as assessed by western blot, with purified capsid protein from SMSV 1 and SMSV 4. Consequently, the SMSV 8 and SMSV 12 virus isolates may not be members of the SMSV/VESV calicivirus group. Using antisera from pigs experimentally inoculated with SMSV and VESV as positive controls, a western blot assay for these virus types was utilized to check for the presence of antibodies to calciviruses in swine sera. Sera from colostrum-deprived gnotobiotic pigs were used as a negative control in all experiments. Examination of sera from domestic and feral swine collected in Iowa, California, and Florida was completed using this technique. The presence of antibodies to these virus types was not detected in any of the porcine sera tested.

Detection of swine caliciviruses by indirect immunofluorescence.

The indirect immunofluorescence test is a rapid method for detecting the presence of vesicular exanthema of swine virus or San Miguel sea lion virus in cell culture. A serological relationship exists between vesicular exanthema of swine virus and San Miguel sea lion virus, as shown by the fluorescence-positive reactions between swine antisera to vesicular exanthema of swine virus A48 and San Miguel sea lion virus type 5 and cell cultures infected with San Miguel sea lion virus types 1, 2, 3, 4 and 5 as well as vesicular exanthema of swine virus B51, C52, D53, E54, F55, G55, H55, I55, J56 and K55. The indirect immunofluorescence test detects group-specific antibody to caliciviruses in swine sera.

Susceptibility of mink to certain viral animal diseases foreign to the United States.

Mink (Mustela vison) were inoculated with viruses: African horse sickness (AHS), African swine fever (ASF), bovine herpes virus II (BHV2), foot-and-mouth disease (FMD), goat pox (GP), hog cholera (HC), peste des petits ruminants (PPR), rinderpest (RP), swine vesicular disease (SVD), vesicular exanthema of swine (VES) and vesicular stomatitis (VS). Their susceptibility was measured by development of clinical signs, virus isolation and detection of precipitin and/or virus neutralizing antibodies. SVD virus produced a lesion in one mink. Virus was isolated from mink inoculated with SVD, FMD and BHV2. Neutralizing and/or precipitin antibodies were detected in mink inoculated with ASF, FMD, GP, RP, SVD and VS viruses. Mink were not susceptible to AHS, HC, PPR and VES viruses.