Swine vesicular disease:

• Swine vesicular disease (SVD) is typically a transient disease of pigs in which vesicular lesion appears in mouth and foot.
• It is usually mild in nature and may infect pigs sub-clinically.
• Disease is of major economic importance because it should be differentiated from FMD, eradication is costly and restriction or stoppage on export of pigs and pork products are often imposed on nations not free of SVD.

Etiology:

• Enterovirus of family Picornaviridae
• It is thought to have evolved from human pathogen coxsackievirus B5
• Virus can survive for long periods in manure
• Virus is resistant to 2% NaOH, 8% formaldehyde, 0.04% of sodium hypochlorite.

Epidemiology:

• Pigs are considered only the natural host of virus, although it can affect sheep in close contact with infected pigs.
• SVD has been reported only in Europe and Asia, having been first identified in Italy in 1966 and subsequently in Hongkong, Japan, Taiwan and other 16 countries in Europe.
• It had remained endemic in Italy and caused sporadic outbreaks of disease in other European countries during the 1990s and in Portugal in 2003, 2004, and 2007.
• As of 2020 it was reported to be eradicated from the Italian pig industry.

Transmission:

• Direct or indirect contact with infected animal or feces
• Direct contact with contaminated environment
• Through contaminated feed and water
• Ingestion of contaminated pork meat.
• Virus excretion; Nose, mouth, feces
• Movement of infected pigs to another farm

Pathogenesis:

• Localization of virus in tonsils, GIT
• Entry through skin abrasion
• Infection followed by viremia
• Virus produce vesicular lesion on coronary band, tongue, lip and snout

Clinical Signs:

• Incubation period is of 2-14 days
• Vesicles and erosion on snout, mammary gland, coronary band, inter-digital areas.
• Transient fever; 104-105°F
• Reduced feed intake
• Lameness and tenderness of feet
• Circling movement, head pressing, convulsion and paralysis
• Lesion are similar to FMD, vesicular exanthema of swine, Seneca valley virus, vesicular stomatitis; however affected pigs donot lose condition and lesions heal rapidly.
• WOAH recommends that any outbreaks of swine vesicular disease in pigs should be assumed to be FMD until proven by laboratory testing.

Diagnosis:

• On the basis of clincal signs and symptoms
• Serological test: CFT, FAT, VNT, ELISA
• Laboratory testing of samples of epithelium, feces or serum

Differential Diagnosis:

1. FMD:

• It also affects ruminants.
• It is indistinguishable and differentiated through laboratory testing.

2. Vesicular exanthema of swine (VES):

• Vesicular disease caused by astrovirus.
• Clinically indistinguishable- vesicles on feet, snout
• Now considered eradicated globally

3. Vesicular stomatitis (VS):

• It is caused by vesiculovirus (Rhabdoviridae)
• It can also affect cattle, horses, pigs
• More pronounced salivation and stomatitis

Treatment and Control Measures:

• Import of pig and pig products from affected countries or region should be restricted.
• Feeding of garbage should be regulated or banned.
• Biosecurity measures is utmost. Restriction of movement of pig on endemic areas.
• Extensive sero surveillance to detect sub-clinical infection.
• Thorough disinfection of premises, vehicles and equipments.
• No effective vaccine has been developed for disease.