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Rinderpest is also known as Cattle plague, is an acute, contagious viral disease of cattle and buffaloes, mild in sheep and goats and also reported in pigs. The virus can be adapted to rabbits in which characteristic chalkwhite necrotic lesions stand out in the payer's patches and in the succulus and the appendix. The virus has been grown on chorio-allantioc membrane of chick embryo. But the passage through goats, rabbits and chick embryo attenuates the virulence. The negative sense single-standard RNA virus is related to the virus of measles and canine distemper.
ROUTES OF INFECTION
- Infection is by ingestion of contaminated feed and water.
- Infection into a herd is usually introduced by an affected animal.
- Infection may also be conveyed by attendants and fomites.
- Inhalation may also be an important route.
INCUBATION PERIOD
- By experimental inoculation - 2 to 3 days.
- Contact infection - 6 to 9 days.
- Outside the body, the virus cannot thrive for more than 24 hours.
- It is rapildy destoryed by sunlight and odinary disinfectants.
SYMPTOMS
- Fever (4th to 6th day after infection)
- Rise in temperature
- Anorexia
- Lachrymation
- Dryness of muzzle
- Congestion of conjuctiva and leucopenia.
- Severe abdominal pain, arched back, staring coat and constipation.
- By about the 7th day the lesions in the mouth develop with dribbling of saliva.
- Severe diarrhoea, animal becomes very much emaciated.
- Animal dies within 6 to 12 days from the onset of symptoms.
PATHOGENESIS
- The virus has great affinity for lymphoid cells and the epithelial cells of alimentary system
- It causes pyknosis and fragmentation of the nuclei in lymphocytes, their necrosis and subsequent disapperance.
- The germinal centers of lymph nodes are bare and do not contain lymphocytes.
- Only the reticulum meshwork remains.
- Other cells- plasma cells and macrophages- may infiltrate such an area.
- The changes are seen in all lymph nodes, the spleen and Peyer's patches.
LESIONS
- Initial lesions on inner surface of lower lip, adjacent gum, cheeks, ventral tongue
- Severe lesion at the pyloric region of abomasum, there necrotic foci accompined by hemorrhagic streaks
- The folds of the abomasum are thick and edematous and the content are chocolate in color due to the presence of blood.
- Diffuse hemorraghes, ulceration with the pseudo-membranous bran-like deposits
at the ileo-cecal valve, at the cecocolic junction and in the rectum. - The hemorrhage streaks on the folds of mucosa of rectum are called zebra marking.
- Petechiae and erosion in the bladder and vagina.
- Lungs- congested and emphysematous. Petechail and hemorrhagic streaks are present.
VACCINES
- Goat tissue adapted vaccine(GTV).
- Tissue culture adapted rinderpest virus vaccine(TCRV).
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