Rinderpest

Rinderpest is a viral disease of cattle

1. RINDERPEST Dr S VIGNESH 19-MVP-37

2. Africa 1890’s

3. Introduction Synonym   : Cattle plaque Acute, highly contagious viral disease of cattle characterized by high fever, necrotic stomatitis, gastroenteritis, diarrhoea and high mortality caused by morbillivirus The virus is antigenically closely related to the viruses of  canine distemper , PPR of sheep and goats and measles of humans Globally eradicated in 2011

4. The need to combat rinderpest outbreaks was instrumental in the establishment of the world’s first veterinary school in 1762 in Lyon, France, and the Office International des Epizooties (OIE) in 1924, also in France In 1994 the Global Rinderpest Eradication Program (GREP) was created to undertake complete eradication n of the disease The principal vaccine used to control rinderpest was the tissue culture rinderpest vaccine (TCRV) produced in calf kidney cells for cattle. Plowright and others developed the vaccine in Kabete, Kenya, in 1957.

5. The last recorded outbreak of lineage 3 virus was in Pakistan in 2000 and of lineages 1 and 2 in Africa in 2001 A joint meeting of the 79th General Session of the OIE and the 37th FAO Conference adopted a resolution declaring the “Global Freedom from Rinderpest” on June 28, 2011. Th e virus still exists in research laboratories in the world. On 14 June 2019 the largest stock of the rinderpest virus was destroyed at the  Pirbright Institute

6. India has been free from clinical Rinderpest since June, 1995. However, as per norms, India submitted the dossier on August, 2005 for obtaining freedom from Rinderpest. The International Committee of World Organization for Animal Health, OIE recognized India as free from Rinderpest infection on 25th May, 2006.

7. Susceptibility Mainly cattle and buffaloes, but also reported in sheep,goat and pigs Reported in deer, antelope, wild buffaloes, wild boars, bushbuck, warthogs and giraffe Mortality is 100 % in exotic breeds and 20-50 % mortality in indigenous breeds

8. Transmission Incubation period is 2 to 3 days in experimental inoculation and in contact infection is 6 to 9 days Virus excreted in body secretions Ingestion of contaminated feed and water Inhalation

9. Pathogenesis The virus is inhaled in infected droplets It penetrates through the epithelium of upper respiratory tract and multiplies in the tonsils and regional lymph nodes From here it enters the blood in mononuclear cells which disseminate to other lymphoid organs, lungs and epithelial cells of mucous membranes Rinderpest virus has a high degree affinity for lymphoid tissue and mucous membrane of alimentary tract Pronounced destruction of lymphocytes in tissues and it is responsible for marked leucopoenia Focal necrotic stomatitis and enteritis are the direct result of viral infection and replication in the epithelial cells in the alimentary tract. Death is usually from severe dehydration but in less acute cases, death may be from activated latent parasitic or bacterial infections These infections aggravate because the animal is immunosuppressed as a result of destruction of lymphoid organs by the virus

10. Clinical signs Fever (104-105  F), restlessness, dryness of the muzzle and constipation Other signs include photophobia, excessive thirst, starry coat, retarded rumination, anorexia and excessive salivation Rashes may develop in those parts of the body where the hair is fine in nature Mucous membrane of lips, gums and tongue revealed small vesicles resembling bran like deposits 'Shooting diarrhoea' with foetid odour Dehydration Marked leucopoenia with drop in lymphocyte count

11. Post mortem findings Virus produce  lesions  in the oral mucosa after settling in the cells following a viremic state Fore stomach are free Abomasum reveals necrotic foci and haemorrhagic streaks more seen at the pyloric region. Folds of abomasum are thick and oedematous If the disease progress, abomasal mucosa shows irregular ulcers of different size. The virus has got affinity for lymphoid tissue and in the intestine, peyer's patches are swollen and ulcerated Duodenum and ileum revealed streaks of haemorrhages and erosions In the large intestine, ileo caecal valve may be markedly swollen

12. Linear haemorrhages on the folds of mucosa of rectum appear like  'Zebra marking'  which is pathognomonic in Rinder pest Lesions  are more severe in large intestine with ulceration and diphtheitic patches Liver: Chronic passive congestion resulting from cardiac and pulmonary complications Petechiae and erosions in the larynx Tracheal haemorrhages Alveolar and interstitial emphysema Subepithelial and subendocardial haemorrhages Petechiae and erosions may be seen in the bladder and vagina Purulent conjunctivitis and ulceration of cornea may be noticed In sheep and goat, mouth  lesions  are usually not seen

13. Histopathology Epithelial surface reveals ulcers, haemorrhages, oedema, necrosis and leucocytic infiltration along with multinucleated cells Eosinophilic cytoplasmic inclusion bodies form in the mucosal epithelial cells and giant cells. Intranuclear inclusion bodies are rare.

14. Samples • Animals showing a pyrexia are probably viraemic and usually the best source of blood for detecting or isolating virus; take blood from several pyrexic animals o sterile whole blood preserved in heparin (10 IU/ml) or EDTA (0.5 mg/ml) and transferred to laboratory on ice (but not frozen); do not use glycerol as preservative transport media as it inactivates RPV o blood for serum, although antibodies are unlikely to be detected until the mucosal phase • Spleen, prescapular or mesenteric lymph nodes of dead animals chilled to sub-zero temperatures for virus isolation • Full set of tissue samples is advised in 10% neutral buffered formalin for histopathology and immunohistochemistry o base of the tongue, retropharyngeal lymph node and third eyelid are suitable tissues • Ocular and nasal secretions of infected animals during either the prodromal or the erosive phase

15. Diagnosis Symptoms and  lesions Complement fixation test (CFT) Agar Gel Precipitation Test (AGPT) Virus isolation and diagnosis on tissue cultures Using specific cDNA probes, isolates of rinderpest and PPR viruses can be differentiated presently Polymerase chain Reaction (PCR)