Vesicular exanthema of swine virus: isolation and serotyping of field samples.

The research article focuses on the study of the Vesicular Exanthema of Swine Virus (VESV), as it details attempts at isolating and serotyping different samples during various outbreaks across the U.S.A. between 1952 and 1954.

Research Methodology

• The study made use of 262 samples collected from the field during outbreaks of the Vesicular Exanthema of Swine Virus (VESV) in the USA between the years 1952 and 1954.
• Primary swine kidney culture was the medium used to attempt virus isolation from collected samples. This method was successful in isolating viral cytopathogenic agents from 76.3% of the samples.
• For those samples initially yielding negative results in tissue culture, they were inoculated intradermally into susceptible swine, which raised the overall virus recovery rate to 82.1%. Inoculating directly into swine allowed viruses that were not demonstrating in the culture medium to manifest as infections in the swine.

Findings and Results

• All isolates of the Vesicular Exanthema of Swine Virus were identified as serotype B51. This was determined through complement fixation and serum neutralization tests, standard methods for virus identification and serotyping.
• Two of the isolates did not exhibit reaction with antisera to known vesicular agents of swine. Upon inoculation in swine, these isolates failed to produce vesicles or any clinical signs of the disease. This could indicate a variant strain of the virus, or perhaps an entirely different pathogen was present in these samples.
• One isolate of the Vesicular Exanthema of Swine Virus, which had originated from equine tissue, was pathogenic for swine, but only produced limited vesiculation at the site of intradermalingual inoculation in the tongue of an experimentally infected pony. A limited reaction to the virus may suggest some species-specific characteristics of the virus, or potentially, some level of resistance or tolerance in equine species.
• The B51 virus was successfully reisolated from the lesions produced in the pony, and the pony was found to be seropositive for the B51 virus type, offering further evidence of the infectivity and virulence of this strain of the virus.