Synonyms: Goat plague, Kata
• Peste des petits ruminants (PPR) is a highly contagious, acute, or subacute viral disease of goats and sheep characterized by fever, erosive stomatitis, conjunctivitis, gastroenteritis and pneumonia.
• This disease was first described in 1942 in West Africa and it is closely related to the rinderpest virus, canine distemper virus and human measles virus.
• Peste des petits ruminants virus (PPRV) is a single-stranded, non-segmented RNA virus belonging to the genus Morbili virus, subfamily Paramyxovirinae, family Paramyxoviridae.
• It is primarily a disease of goats and sheep. Goats, particularly young ones, (4 months to 1 year of age) are usually more severely affected than sheep.
• The infection also occurs in wild ungulates.
• Cattle, buffaloes, camels and pigs are rarely susceptible. They do not exhibit clinical signs and are unable to transmit the disease to other animals.
• Transmission requires close contact between animals. Infection occurs mainly through inhalation of aerosols and by ingestion. There is no known carrier state. The spread is not dependant on vectors.
- History of recent movement or gathering together of sheep and/or goats of different ages
- Introduction of recently purchased animals
- Change in weather such as the onset of the rainy season or dry, cold periods
- Contact with a trade or nomadic animals.
• Incubation period is 6 days.
- Fever and serous rhinorrhoea – Erosions in the mucous membranes lining the upper alimentary, upper respiratory, and urogenital tracts for first 1-2 days followed by fever
- Profuse salivation, protruded and retracted tongue.
- Rhinorrhea becomes mucopurulent often blocks the nostrils
- Diarrhoea and pneumonia.
Per acute form
- Follow incubation period that is often as short as 2 days
- Profuse nasal catarrh precedes a sudden high fever with signs of depression, dyspnoea, anorexia and constipation
- Diarrhoea, leucopenia
• Live animals: Buccal and rectal mucosa, tears, whole blood (buffy coat), nasal secretions, faeces and gum debris.
• Dead animals: Oral mucosa, tonsils, lungs, small, large intestines and mesenteric lymph nodes.
Diagnosis is based on
- Classical clinical signs
- Virus isolation and identification in cell cultures
- Demonstration of viral antigen in the buffy coat, body secretions, faeces, lymph nodes and tonsils by immunohistochemical methods, dot-ELISA, AGID and CIEP.
Note: unlike rinderpest, PPR viral antigen is still high in tissues of animals dying from the disease.
- Serology: Virus neutralization tests (VNT) and competitive ELISAs recommended serologically tests by OIE.
- Complement Fixation Test and AGID are most commonly. More recently ELISA has been developed based on monoclonal antibodies specific for the N or H proteins of PPR and rinderpest viruses, and which enable differential diagnosis of the two viruses.
• Rinderpest: Affects both cattle and small ruminants. The symptoms are very severe in cattle than in small ruminants.
• Pasteurellosis: The disease is characterized by obvious respiratory signs, infrequent diarrhoea, and a mortality rate rarely exceeding 10 per cent. The bipolar organisms can be readily demonstrated in smears.
• CCPP: There is no digestive system involvement, and the clinical signs and lesions are confined to the respiratory system and pericardium.
• Bluetongue: Sheep are mostly affected. Swelling of the lips, muzzle, oral mucosa and coronitis are more common.
• Contagious ecthyma: Proliferative necrotic lesions seen in the lips rather than the whole oral cavity. The absence of nasal discharges and diarrhoea also distinguish orf from PPR.
Prevention and control
- There is no treatment for PPR.
- Oxytetracycline and chlortetracycline prevent secondary bacterial infections.
- Hyperimmune serum from cattle hyperimmunized against rinderpest
- Quarantine of the newly purchased animals, isolation of the affected animals, and following strict hygienic measures will help to control the disease.
- vaccinate sheep or goats with PPR vaccine at the age of 6 months and booster dose once a year.
- The tissue culture rinderpest vaccine at a dose of 102.5 TCID50 protects goats for at least 12 months against PPR.
- This vaccine is safe for pregnant goats.
- A homologous PPR tissue culture vaccine produced by attenuation in Vero cells is commercially available.
- Newly developed recombinant vaccinia or capripox viruses expressing the fusion (F) and Haemagglutinin (H) protein genes of the rinderpest virus are also effective against PPR.
Source: Pirbright Institute