''Vesicular exanthema of swine virus'' (VESV) is a virus which produces a disease in pigs that is clinically indistinguishable from the viruses causing

foot-and-mouth disease Foot-and-mouth disease (FMD) or hoof-and-mouth disease (HMD) is an infectious and sometimes fatal viral disease that affects cloven-hoofed animals, including domestic and wild bovids. The virus causes a high fever lasting two to six days, followe ...

(FMD) and

swine vesicular disease Swine vesicular disease (SVD) is an acute, contagious viral disease of swine caused by swine vesicular disease virus, an ''Enterovirus''. It is characterized by fever and Vesicle (dermatology), vesicles with subsequent ulcers in the mouth and on ...

(SVD). VESV affects only pigs and marine mammals. It is not transmissible to humans. VESV is only a concern among Californian pig-farmers; otherwise, the disease is now, by and large, a historical curiosity. It was globally eradicated in swine in 1959.Vesicular Exanthema—Pig
expert reviewed and published by WikiVet, accessed 10 October 2011.

Source of virus

Viruses that are virtually identical to VESV are present in marine mammals and fish along the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...

of the United States. These viruses are sometimes called San Miguel Sea Lion Virus. It is therefore assumed that the source of VESV was waste seafood fed to pigs or as garbage finding its way to pigs from

farmed Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peop ...

mink Mink are dark-colored, semiaquatic, carnivorous mammals of the genera ''Neogale'' and '' Mustela'' and part of the family Mustelidae, which also includes weasels, otters, and ferrets. There are two extant species referred to as "mink": the A ...

that were fed

seafood Seafood is any form of sea life regarded as food by humans, prominently including fish and shellfish. Shellfish include various species of molluscs (e.g. bivalve molluscs such as clams, oysters and mussels, and cephalopods such as octopus an ...

History

VESV 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, with the pigs being slaughtered each time. Then, in 1952, the virus escaped from California in a trainload of infected pork. Garbage-fed pig

herd A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called ''herding''. These animals are known as gregarious animals. The term ''herd'' is ...

s came down with the disease, and it spread from them to neighboring 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 United States in 1959. The only cases outside the United States were in slaughter pigs on ships from the U.S. 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, the San Miguel sea lion virus (SMSV) was isolated from San Miguel Island sea lions. When inoculated experimentally into pigs, it caused typical signs of VESV.

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.

Symptoms

Symptoms are very similar to FMD and include: * Fever up to . * Vesicles on the

epithelium Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...

of the

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is c ...

, lips, nostrils, tongue, feet and mammary glands. * Epithelial lesions identical to the other vesicular diseases. * No systemic lesions. Mortality is low, but there may be some deaths in suckling piglets. Growing pigs may become debilitated.

Diagnosis

Diagnosis requires laboratory tests. Serological methods such as

complement fixation The complement fixation test is an immunological medical test that can be used to detect the presence of either specific antibody or specific antigen in a patient's serum, based on whether complement fixation occurs. It was widely used to diagnos ...

, serum neutralization and

PCR PCR or pcr may refer to: Science * Phosphocreatine, a phosphorylated creatine molecule * Principal component regression, a statistical technique Medicine * Polymerase chain reaction ** COVID-19 testing, often performed using the polymerase chain r ...

are available.

Virology

Virions consist of a capsid. Virus capsid is not enveloped, round with icosahedral symmetry. The

isometric The term ''isometric'' comes from the Greek for "having equal measurement". isometric may mean: * Cubic crystal system, also called isometric crystal system * Isometre, a rhythmic technique in music. * "Isometric (Intro)", a song by Madeon from ...

capsid has a diameter of 35–39 nm. Capsids appear round to hexagonal in outline. The capsid surface structure reveals a regular pattern with distinctive features. The capsomer arrangement is clearly visible. Capsid with 32 cup-shaped depressions. Under in vitro conditions, virions are inactivated in acid environment of pH 3–5. The genome is not segmented and contains a single molecule of linear positive- sense, single-stranded

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

. Minor species of non-genomic

nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...

are also found in virions. The complete genome is 7900 nucleotides long. The

5'-end Directionality, in molecular biology and biochemistry, is the end-to-end chemical orientation of a single strand of nucleic acid. In a single strand of DNA or RNA, the chemical convention of naming carbon atoms in the nucleotide pentose-sugar-ri ...

of the genome has a viral protein genome-linked ( VPg). The 3'-terminus has a poly (A) tract. The genome encodes viral structural proteins. Lipids are not reported. By itself, the genomic nucleic acid is infectious.

Management control and prevention

No vaccines are available. The cooked garbage policy in the United States should prevent its reappearance. Pigs should not be fed waste seafood.

Notes

References

ThePigSite Pig Health

* ICTVdB Management (2006). 00.012.0.01.001. Vesicular exanthema of swine virus. In
ICTVdB—The Universal Virus Database, version 4
Büchen-Osmond, C. (Ed), Columbia University, New York, USA {{Use dmy dates, date=April 2017 Vesiviruses Swine diseases Animal viral diseases