SWINE VESICULAR DISEASE

Description:

A contagious disease of swine caused by a porcine enterovirus of the family Picornaviridae, closely related to the human enterovirus Coxsackie B-5, and characterized by vesicular lesions and erosions of the epithelium of the mouth, nares, snout, and feet; human infections have been reported in laboratory workers.

Abbreviation: SVD.

The incubation period is usually 2 to 7 days, but it can be longer if the dose of virus is small.

Swine vesicular disease is a viral disease, characterized by the formation of vesicles and erosions that affects only pigs. Although it can cause mild to severe illness, this infection is transient and not life-threatening. Its main significance is the strong resemblance to other vesicular diseases, particularly foot-and-mouth disease. Rapid differentiation of these diseases is critical, as the introduction of foot-and-mouth disease could cause severe economic losses in non-endemic regions. In addition, the stability of swine vesicular disease virus in the environment complicates its eradication and makes prompt recognition essential for control.

Swine vesicular disease was formerly endemic in much of Europe, but it has been eradicated from all areas except southern Italy. Occasional outbreaks still occur throughout Europe from imported viruses. SVDV was also found in some parts of Asia in the past, and it is still thought to be endemic there.

Symptoms:

Symptoms include:

Fever.

• Vesicles in the mouth and on the snout and feet.

• Ruptured vesicles can cause ulcers on limbs and feet, and foot pads may be loosened.

• Lameness and an unsteady gait, shivering and jerking-type leg movements.

Causes and Risk Factors:

The disease has been recorded in Hong Kong, Japan and several European countries. Virus readily infects via lesions in skin and mucosa. SVDV is highly contagious by direct contact with infected animals or via environmental contamination. This virus can enter the body through broken skin or mucous membranes, and by ingestion. Pigs can excrete SVDV in nasal or oral secretions and feces up to 40 to 48 hours before clinical signs are seen. Porcine tissues can also transmit infections if undercooked pork meat or other scraps are fed to swine. Most pigs eliminate the virus within two weeks, with highest viral shedding during the first week, but in rare cases, animals can remain infected for three months or longer. In these persistent carriers, SVDV has been found in nasal secretions and tonsillar tissues, and for particularly long periods in feces. Airborne transmission of this virus is insignificant, and it may not spread between pens unless there is a common open drainage system or the pigs are moved or mixed.

Diagnosis:

Vesicular diseases are clinically indistinguishable and must be differentiated with laboratory tests.

Swine vesicular disease is often diagnosed by detecting viral antigens in lesion material with an ELISA (enzyme-linked immunosorbent assay).

• Immunohistochemistry may also be used. If insufficient material is available for antigen testing (less than 0.5 g) or the test results are negative or inconclusive, virus isolation can be done.

• RT-PCR can also detect SVD in clinical samples including feces.

• Swine vesicular disease is often diagnosed by serology.

Differential Diagnosis:

1. Foot-and-mouth disease.

2. Vesicular stomatitis.

3. Vesicular exanthema of swine.

4. Chemical or thermal burns.

Treatment:

There is no vaccine for SVD. Prevention measures are similar to those for foot-and-mouth disease: controlling animals imported from infected areas, and sanitary disposal of garbage from international aircraft and ships, and thorough cooking of garbage. Infected animals should be placed in strict quarantine. Eradication measures for the disease include quarantining infected areas, depopulation and disposal of infected and contact pigs, and cleaning and disinfecting contaminated premises.

Laboratory workers should observe the same caution that applies to any microbiologically contaminated material that may have the potential to cause human infection

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.