Vesicular Exanthema of Swine
Geographic distribution:
Vesicular exanthema of swine (VES) is a disease that has been eradicated from the world. Currently the virus only exists in some biological freezers in various virologists' laboratories. The disease arose in southern California in 1933 and subsequently spread across the United States, curiously cropping up adjacent to a transcountry railroad line at each post where garbage was extruded. In the 1950's, national efforts to eradicate the disease were successful and there have been no new cases since 1959. It is now believed that the initial outbreak was caused when a closely related virus present in fish or sea mammals was fed to pigs, became adapted for pigs, and then spread among them.
Etiology:
Vesicular exanthema of swine virus (VESV), is a member of the Genus Calicivirus, Family Caliciviridae. Since its discovery, numerous marine caliciviruses have been identified and described, the most closely related one being San Miguel Sea Lion Virus (SMSV). Inoculation of SMSV into pigs causes vesicles to form in the pigs but there is no subsequent transmission among pigs. All caliciviruses are single stranded RNA viruses.
Susceptibility:
Swine are the only species known to be susceptible to VES.
Zoonosis:
Not transmissible to humans.
Transmission:
Once established within a herd, transmission from pig to pig is by direct contact. Initiation of new outbreaks starts by feeding infected uncooked pork scraps. The original spread of the disease across the U.S. is probably due to discarding of pork scraps along a transcontinental train route and subsequent scavaging by pigs of those pork scraps.
Clinical Signs:
Gross lesions:
Epithelial lesions are identical to the other vesicular diseases.
No systemic lesions
Diagnosis:
Must distinguish from foot-and-mouth disease, vesicular stomatitis, and swine vesicular disease.
Do not attempt to make a final differential diagnosis in the field! Call your state and/or federal veterinarian!
Differential Diagnosis
Treatment and Control:
Slaughter and disposal of infected and contact animals and disinfection of the premises.
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