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ARS Home » Research » Publications at this Location » Publication #184770
Title: SWINEPOX

Author
item Delhon, Gustavo
item TULMAN, EDAN - UNIV. OF CONNECTICUT
item AFONSO, CLAUDIO - USDA, ARS, ATHENS, GA
item ROCK, DANIEL - UNIV. OF ILLINOIS

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 7/1/2005
Publication Date: 10/31/2005
Citation: Delhon, G., Tulman, E.R., Afonso, C.L., Rock, D.L. 2005. Chapter 29 Swinepox. Barbara Straw, Editor, Diseases of Swine, Ninth Edition, Iowa State Press, Ames, Iowa, Blackwell Publishing, p. 483-487.

Interpretive Summary:

Technical Abstract: Swinepox (SWP), a mild and acute disease of swine characterized by eruptive dermatitis, is caused by swinepox virus (SWPV) of the genus Suipoxvirus of Poxviridae. SWPV is morphologically similar to vaccinia virus, and contains a double-stranded DNA genome, which encodes for 150 genes, including a unique complement of genes with perdicted functions in host range and virulence. Due to its restricted host range, SWPV has been proposed as a vaccine expression vector. SWP is present worldwide and is usually associated with poor sanitation. Clinical disease is most often seen in young animals, with morbidity rates as high as 100% and mortality rates rarely exceeding 5%. Transmission in nature has been associated with louse infestation, but other vectors or mechanisms of tranmission may be implicated in disease spread. Vertical transmission has been documented. In natural conditions, SWP has an incubation period of 4-14 days. The disease is characterized by cutaneous lesions on the flanks, belly, inner side of the legs, and ears, and by slight and transient fever. Skin lesions follow the pattern maculae-papulae-crust observed in many poxviral diseases, with complete recovery observed 15-30 days post-exposure. Fully developed papulae are 1-2 cm in diameter and become umbilicted about a week after appearing. Histologically, papulae are characterized by hyperplasia, vacuolar degeneration, and chromatin margination in epideramal and hair follicle keratinocytes, and leukocyte infiltration in the underlying dermis. Cytoplasmic inclusion bodies and viral antigen can be detected in affected keratinocytes and in dermal macrophages. Convalescent swine are resistant to SWPV challenge, indicating that infection induces protective immunity. Presumptive SWP diagnosis is based on the observation of pox lesions in the skin. SWPV involvement can be confirmed by electron microscopy of skin lesions or by virus neutralization using SWPV-specific antibodies following virus isolation. No vaccine against SWPV has been developed.