Synonym : Cattle plaque
Definition
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Acute, highly contagious viral disease of cattle characterized by high fever, necrotic stomatitis, gastroenteritis, diarrhoea and high mortality caused by morbillivirus
Etiology
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Morbillivirus
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The virus is antigenically closely related to the viruses of canine distemper, PPR of sheep and goats and measles of humans.
Incidence
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The disease has been the foremost cause of death in cattle in most African and Asian countries including India
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Rinderpest has not been reported since June 1995 in Indian suncontinent
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The seriousness of disease madeto start first Veterinary College in 1762 at Lyons, France.
Susceptibility
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Mainly cattle and buffaloes, but also reported in sheep,goat and pigs
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Reported in deer, antelope, wild buffaloes, wild boars, bushbuck, warthogs and giraffe
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Mortality is 100 % in exotic breeds and 20-50 % mortality in indigenous breeds
Transmission
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Incubation period is 2 to 3 days in experimental inoculation and in contact infection is 6 to 9 days
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Virus excreted in body secretions
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Ingestion of contaminated feed and water
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Inhalation (or) mechanical transmission
Pathogenesis
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The virus is inhaled in infected droplets
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It penetrates through the epithelium of upper respiratory tract and multiplies in the tonsils and regional lymph nodes
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From here it enters the blood in mononuclear cells which disseminate to other lymphoid organs, lungs and epithelial cells of mucous membranes
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Rinderpest virus has a high degree affinity for lymphoid tissue and mucous membrane of alimentary tract
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Pronounced destruction of lymphocytes in tissues and it is responsible for marked leucopoenia
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Focal necrotic stomatitis and enteritis are the direct result of viral infection and replication in the epithelial cells in the alimentary tract.
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Death is usually from severe dehydration but in less acute cases, death may be from activated latent parasitic or bacterial infections
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These infections aggravate because the animal is immunosuppressed as a result of destruction of lymphoid organs by the virus
Clinical Signs
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Fever (104-105 0F), restlessness, dryness of the muzzle and constipation
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Other signs include photophobia, excessive thirst, starry coat, retarded rumination, anorexia and excessive salivation
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Rashes may develop in those parts of the body where the hair is fine in nature
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Mucous membrane of lips, gums and tongue revealed small vesicles resembling bran like deposits
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'Shooting diarrhoea' with foetid odour
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Dehydration
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Marked leucopoenia with drop in lymphocyte count
Gross lesions
Virus produce lesions in the oral mucosa after settling in the cells following a viremic state
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Fore stomach are free
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Abomasum reveals necrotic foci and haemorrhagic streaks more seen at the pyloric region.
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Folds of abomasum are thick and oedematous
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If the disease progress, abomasal mucosa shows irregular ulcers of different size.
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The virus has got affinity for lymphoid tissue and in the intestine, peyer's patches are swollen and ulcerated
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Duodenum and ileum revealed streaks of haemorrhages and erosions
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In the large intestine, ileo caecal valve may be markedly swollen
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Linear haemorrhages on the folds of mucosa of rectum appear like 'Zebra marking' which is pathognomonic in Rinder pest
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Lesions are more severe in large intestine with ulceration and diphtheitic patches
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Liver: Chronic passive congestion resulting from cardiac and pulmonary complications
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Petechiae and erosions in the larynx
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Tracheal haemorrhages
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Alveolar and interstitial emphysema
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Subepithelial and subendocardial haemorrhages
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Petechiae and erosions may be seen in the bladder and vagina
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Purulent conjunctivitis and ulceration of cornea may be noticed
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In sheep and goat, mouth lesions are usually not seen
Microscopic lesions
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Epithelial surface reveals ulcers, haemorrhages, oedema, necrosis and leucocytic infiltration along with multinucleated cells
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Eosinophilic cytoplasmic inclusion bodies form in the mucosal epithelial cells and giant cells. Intranuclear inclusion bodies are rare.
Diagnosis
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Complement fixation test (CFT)
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Agar Gel Precipitation Test (AGPT)
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Virus isolation and diagnosis on tissue cultures
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Using specific cDNA probes, isolates of rinderpest and PPR viruses can be differentiated presently
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Polymerase chain Reaction (PCR)
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