Ovine Rinderpest/PPR Dr.Kedar Karki
Background • Ovine rinderpest, also commonly known as peste des petits ruminants (PPR), is a contagious disease affecting goats and sheep in Africa (from Tropic of Cancer to Equator), the Middle-East and the Indian subcontinent. But since June 2008, the disease invaded Morocco , which indicates a crossing of the natural barrier of Sahara. It is caused by a species of the Morbillivirus genus of viruses. The disease is highly contagious, and has roughly an 80 percent mortality rate in acute cases.
Disease appellations • In the first time, kata was the appellation of a stomatitis and pneumoenteritis of Nigerian dwarf goat. Peste des Petits Ruminants was the French name of a similar disease in sheep and goat first described in Ivory Coast in 1942. Both diseases were shown to be very close to each others.
• Many authors prefer the appellation of "Ovine Rinderpest". But official instances like FAO and OIE use the French name "Peste des Petits Ruminants", "Peste Des Petits Ruminants", "Peste-des-PetitsRuminants" or "Peste-des-petitsruminants", even in English.
Geographical repartition • The disease is present in West Africa, part of Central Africa ( Gabon, Central African Republic), East Africa (North of the Equator), Middle East and Indian subcontinent including Nepal and Burman.
• In North Africa, only Egypt was once hit. But since summer 2008, Morocco is suffering a generalized outbreak with 133 known cases in 129 provinces, mostly affecting sheep. The outbreak has precipitated the vaccination of a large amount of the 17 million sheep and five million goats in the country
• The disease is spread from a region to another by sick animals. As virus is early inactivated outside the body, indirect contamination is generally limited. • In an affected flock, even in pest-free regions, the disease do not progress very rapidly, although close contact between animals. New clinical cases may be oberved daily for a one-month period.
Symptoms • They are similar to those of rinderpest in cattle. They vary following the previous immunitary status of sheep (enzootic or newly infected country). They also vary following sheep breed. • Incubation period is two to six days.
Hyperacute cases • Hyperacute cases are found dead without previous symptoms. They die with a serous, foamy or haemorrhagic discharge coming out of the nose.
Acute cases at onset • In acute cases, animals are recumbent, sometimes in self-auscultation position. • Body temperature is high (40.5 to 41°C.) in the beginning of the onset in acute cases. • The most typical signs are seen in the digestive tract. When entering an affected flock, one sees many animals with hind limbs stained by sticky faeces. Some sheep have an arched back and show pain to defecate. Tenesmus may be noticed when taking rectal temperature. Fluid faeces are olive green to brown.
• Examination of the mouth shows ulceration of the buccal mucosae, especially on the inner face of the lips, and neighboring gum. They can be periodontitis. • There is serous nasal exsudate and conjunctivitis.
Evolution of acute cases • Nasal discharge becomes mucopurulent and may obstruct the nose. • A dry, fitfull coughing develops. • Death occurs from 5 to 10 days after the onset of the fever. • Some animals may recover, but a dry, stertorous coughing often persists for some days. • Besides coughing, there is a intensive labial dermatitis with scab formation, resembling orf.
Self-auscultation in an acute case/@drkedark
Hind legs stained with sticky diarrhorea/@drkedark
Arched back (painfull defecation)/@drkedark
inflammation and erosion of the mouth/@drkedark
Periodontitis/@drkedark
Mucopurulent nasal exsudate/@drkedark
Orf-like scabs on lips in a recovering case, Day 8/@drkedark
Post-mortem lesions • Field veterinarians should be aware that the pathognomonic lesions are situated in the digestive tract. Quick post-mortem examination will lead to the discovery of many haemorrhagic patches on the serous membranes, and intense pneumonia. They is a risk is to conclude to enzootic pneumonia, and not open the mouth, oesophagus and different parts of intestine.
• Erosions and inflammation is widespread on buccal mucosa. The same lesions are also present in pharynx, oesophagus, and on mucus-producing epithelia of the gut, from abomasum to rectum. Zebrastriped lesions on coecum and colon are said to be typical in some cases. Rarely, they are also petechiae on the rumen mucosa.