Difference between revisions of "Rotaviruses"

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[[Category:Reoviridae]]
 
[[Category:Reoviridae]]
 
[[Category:Cattle Viruses]][[Category:Sheep Viruses]][[Category:Horse Viruses]][[Category:Dog Viruses]][[Category:Cat Viruses]][[Category:Goat Viruses]]
 
[[Category:Cattle Viruses]][[Category:Sheep Viruses]][[Category:Horse Viruses]][[Category:Dog Viruses]][[Category:Cat Viruses]][[Category:Goat Viruses]]
[[Category:Alimentary Diseases - Cattle]][[Category:Alimentary Diseases - Sheep]][[Category:Intestinal Diseases - Horse]][[Category:Intestinal Diseases - Dog]][[Category:Intestinal Diseases - Cat]]
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[[Category:Alimentary Diseases - Cattle]][[Category:Alimentary Diseases - Sheep]][[Category:Small Intestinal Diseases - Horse]][[Category:Intestinal Diseases - Dog]][[Category:Intestinal Diseases - Cat]]
 
[[Category:Enteritis,_Viral]][[Category:Enteritis, Villus Atrophy]]
 
[[Category:Enteritis,_Viral]][[Category:Enteritis, Villus Atrophy]]
 
[[Category:To_Do_-_Clinical/Viruses]]
 
[[Category:To_Do_-_Clinical/Viruses]]

Revision as of 12:31, 17 January 2011



Antigenicity

  • 5 distinct antigenic groups: A to E
  • A is the most commonly seen and studied
  • A is further subdivided to G and P types

Hosts

  • RVs are thought to be mostly species specific, but some transmission between species occurs
  • Group A is present in all mammals
  • Groups B and C are common in pigs but not fully understood

Pathogenesis

  • Strains vary in virulence but are always confined to the gut
  • Incubation: 1-4 days
  • Target tissue: small intestine enteroycte
    • Infected enterocytes are shed, villi shorten, and become covered with immature cuboidal epithelium
    • As such, absorption is compromised
  • Results in white scour
  • NO viremia: confined to GIT
  • Associated symptoms:
    • Weight loss
    • Depression
    • Dehydration
  • Can be fatal if unchecked

Epidemiology

  • Occurs in neonates of most species, although the role of RVs in lamb and foal diarrhoea is less certain
  • NOT associated with diarrhoea in dogs and cats
  • Group A RVs are endemic in domestic animals worldwide
  • Orofecal transmission, highly infectious
  • Excreted in feces as maternal antibody wanes (calves: 2 weeks, piglets: post-weaning)

Diagnosis

  • On feces:
    • ELISA and Latex agglutination
  • On sera:
    • Rising antibody titres are not particularly helpful as most animals show high Ab levels from passive immunity

Control

  • Ensure maternal antibody transfer through the reception of colostrum
  • Hygiene and management strategies: all-in/all-out, isolation of sick animals, etc.
  • Fluid therapy where necessary
  • Dam vaccine:
    • Boost and prolong Ab secretion during suckling
    • Primarily for beef suckler herds as dairy calves receive batch milk after 24 hours

Vilous atrophy in Enteritis

  • Affects young foals and calves.

Pathology

Gross
Histopathology
  • Loss of villus epithelium
    • Replacement with cuboidal or squamous cells
  • Villus atrophy.
  • Relatively mild inflammation.
  • Coronavirus in young calves results in similar pathological changes.