کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2467884 | 1555408 | 2010 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Assessing virulence of vaccine strains of Mycobacterium avium subspecies paratuberculosis in a calf model
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم دامی و جانورشناسی
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چکیده انگلیسی
The purpose of this investigation was to characterise the virulence of two Mycobacterium avium subspecies paratuberculosis (M.a. paratuberculosis) vaccine strains and compare them with a recent virulent isolate in new born calves over a time course of 8 months post-inoculation. Paratuberculosis-free new born calves were inoculated orally with either a vaccine strain (2e or 316F) or a wild type strain (F13) of M.a. paratuberculosis. Blood and faecal samples were collected throughout the experiment to analyse immune responses to infection and assess faecal shedding of M.a. paratuberculosis. Tissue samples were taken at post-mortem for histological examination and bacteriological culture. Cell-mediated immune responses were measured using a Bovigam (CSL) interferon-gamma assay. At 20 weeks post-inoculation there was a significant increase in the cell-mediated immune responses in calves infected with the wild type strain relative to the two vaccine strains. Acid fast bacteria were detected in the faeces of calves in all three groups between 4 and 8 weeks post-inoculation. Histopathology was unrewarding in all three groups. M.a. paratuberculosis was recovered only from tissues of calves inoculated with the wild type strain. Therefore, it appeared that the vaccine strains used in this study had reduced virulence. Identifying the genes responsible for pathogenesis observed in the wild type isolate and reduced or inactive in these vaccine isolates may offer a valuable resource for improving our knowledge of pathogenesis and permit the development of improved diagnostic reagents and vaccines for the control of M.a. paratuberculosis in livestock.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Veterinary Microbiology - Volume 146, Issues 1â2, 20 November 2010, Pages 63-69
Journal: Veterinary Microbiology - Volume 146, Issues 1â2, 20 November 2010, Pages 63-69
نویسندگان
Craig Watkins, Alex Schock, Linda May, Susan Denham, Jill Sales, Louise Welch, J. Michael Sharp, Karen Stevenson,