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Vesicular Exanthema of Swine (VES)

(552) The virus of vesicular exanthema of swine (VES) is different from those causing foot-and-mouth disease (FMD) and swine vesicular disease (SVD) but it produces a disease in pigs that is clinically indistinguishable from FMD and SVD both of which are described in detail above. Unlike FMD it only effects pigs.

You only need be concerned about VES if you have a pig farm in California, near the West coast. To everyone else it is no more than an historical curiosity. This account is therefore brief.

Importance of VES

Infact it has not occurred since 1959 but the virus is still present in sea mammals and fish so it could occur again and you should not dismiss it completely.

The main importance of VES is that clinically it resembles FMD and if it occurred again a slaughter policy would be applied.

Where is it?
Viruses that are virtually identical to VES virus are present in marine mammals and fish along the Pacific coast of the USA. It is therefore assumed that the source of VES was waste sea food fed to pigs as garbage or finding its way to pigs from farmed-mink fed sea-food.

The story of VES is unusual. It was first diagnosed in pigs in Southern California in 1932. Because of its close similarity to FMD all the pigs were destroyed. It kept reappearing in California from time to time, the pigs being slaughtered each time. Then in 1952 the virus escaped from California in a train-load of infected pork. Garbage fed pig herds came down with the disease and it spread from them to neighbouring herds until herds in 43 states were affected. It was eventually stamped out in 1956 by a major slaughter policy combined with a ban on feeding uncooked garbage to pigs. It was declared an exotic disease in the USA in 1959

The only cases outside the USA were in slaughter pigs on ship from the USA bound for Hawaii in 1947 and in pigs fed uncooked pork scraps from an American military base in Iceland in 1955.

The source of the virus remained a mystery until 1972 when an essentially similar virus was isolated from San Miguel sea lions. When inoculated experimentally into pigs it caused typical signs of VES.

Clinical signs

VES does not affect cattle, sheep, goats or any species other than the pigs and sea mammals. So, unlike FMD, if you keep other livestock they will not be affected.

Clinical signs of VES are much the same as FMD so read the section on FMD. Mortality is low but there may be some deaths in sucking piglets. Growing pigs may become debilitated.


This is the same as for suspected FMD and SVD and requires laboratory tests to identify it.

Management control and prevention

  • No vaccines are available.
  • The cooked garbage policy in the USA should prevent its reappearance but its conceivable that an ignorant or careless person may break the rules.
  • If you farm in California do not feed waste sea food to your pigs. Also, do not allow anyone working in your herd to take sandwiches or other food into the pig buildings. Provide a designated eating place for them away from the pigs. This is a good policy anyway.

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