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Malignant Catarrhal Fever Virus (view source)
Revision as of 18:15, 29 October 2008
, 18:15, 29 October 2008no edit summary
====Pathogenesis====
====Pathogenesis====
*Sporadically induce a fatal over-active T cell division, where virus encodes anti-apoptotic protein in dead-end host
[[Image:MCF1.gif|right|thumb|125px|<small><center>Sever Oculo-nasal Discharge of MCF (Courtesy of Alun Williams (RVC))</center></small>]]
*'''Latent''' infection
*Clinical signs in cattle: [[Image:MCF2.gif|right|thumb|125px|<small><center>Fissures on tongue (no vesicles) in MCF (Courtesy of Alun Williams (RVC))</center></small>]]
**Necrotising lesions in upper respiratory tract and eye: conjunctivitis and corneal oedema / opacity (keratitis or "blue eye" - characteristic feature)
**Fever and [[Intestine Diarrhoea - Pathology|diarrhoea]] with severe oculo-nasal discharge
**Not eating, dull with ulcers on muzzle may spread to rest of face with brown exudate
**Ulcers also on tongue, dental pad, and cheeks that regularly become secondarily infected
**Lymphocyte proliferation progresses in lymphoid tissue and blood until death
*Lymph nodes completely replaced by [[Lymph Nodes - Anatomy & Physiology#Follicles|lymphoblasts]] - similar to [[lymphosarcoma]]; synonym lymphoma. (resembles lymphotropic herpes virus such as [[Epstein Barr]])
*Also vasculitis with medial necrosis of blood vessels throughout body with infiltration of walls of vessels by [[Lymphocytes - WikiBlood|lymphocytes]].
*Ulcers are due to hypoxia of epithelium resulting from vascular lesions
*Sporadically induce a fatal '''over-active T cell division''', where virus encodes anti-apoptotic protein in dead-end host
*'''Latent''' infection that is invariably fatal
*Virus excretion increased during periparturient period
*Virus excretion increased during periparturient period
*Clinical signs in cattle:
**Necrotising lesions in upper respiratory tract, [[Cavity & Gingiva - Pathology#Malignant Catarrhal Fever|gingiva]] and eye
====Epidemiology====
**Lymphocyte proliferation progresses in lymphoid tissue and blood until death
*Not all that common in UK
*Affects whole body but especially evident clinically in face and mouth
*Sporadic and often seen in animals mixing with sheep (carriers)
*In parts of Africa see long outbreaks (diff serotypes) carried by Wildebeest
*In deer produces very serious outbreaks, probably primarily sheep virus
*Often youngish animal 6 months to 1 year
====Control====
====Control====
*Wildebeest should not be stocked in zoos where possible
*Wildebeest should not be stocked in zoos where possible
*Sheep and deer should be housed separately
*Sheep and deer should be housed separately