Author
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Elliott, Margaret |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 1/12/2006 Publication Date: 5/25/2006 Citation: Elliott, M. 2006. In vivo virulence of bovine papillomatous digital dermatitis-associated spirochetes in a murine model [abstract]. Poster Session 2, Paper No. #51. Interpretive Summary: Technical Abstract: Papillomatous digital dermatitis (PDD), also known as hairy heel wart, is a growing cause of lameness of cows in the U.S. dairy industry. Farms with PDD afflicted cows experience economic loss due to treatment costs, decreased milk production, lower reproductive efficiency and premature culling. While the exact cause of PDD is still unknown, lesion development is associated with the presence of anaerobic spirochetes. Previous work using lesion material from a dairy farm in Iowa resulted in the isolation of four different Treponema phagedenis-like spirochetes (1A, 3A, 4A and 5B). In vivo virulence of these PDD isolates was evaluated using a mouse abscess model. Lesion development and antibody response were measured. Lesion size and total IgG produced were dose dependent for all groups. Mice injected with 1A developed significantly larger abscesses than other groups with some mice having lesions unresolved by day thirty-five. Isolate 3A induced skin necrosis by day two and fairly large open lesions by day seven. IgG1 was the predominant IgG subclass produced at fourteen days post injection with differing cross-reactivity occurring between isolates. These data show that spirochetes isolated from PDD lesions have differential virulence and antigenic traits in vivo. Continuing investigation of these properties is important for the elucidation of virulence mechanisms and antigenic targets for vaccine development. |
