Peste des petits ruminants (PPR) is an acute, highly contagious viral disease of goats and sheep caused by peste des petits ruminants (PPR) virus which belongs to the genus Morbillivirus of the family Paramyxoviridae. The disease is characterized by fever, anorexia, necrotic stomatitis, diarrhoea, oculo-nasal purulent discharge and respiratory distress. Infection is mainly transmitted by inhalation or through conjunctiva and oral mucosa. PPR virus penetrates the retropharyngeal mucosa and enters the blood. Virus localizes in alimentary, respiratory and lymphoid system and causes diahorrea, dehydration and death.PPR is rinderpest like disease in Africa and Asia and highly fatal in goats and less so in sheep. Case fatality rate in goats is 55-85% and in sheep it is less than 10%. Goat kids aging between 4 months and 1 year are most susceptible. The disease was first described in West Africa in 1942. In India, it was first reported in Tamilnadu in the year 1989 and subsequently from other states of India. The disease was first confirmed in Andhra Pradesh in 1991 using specific molecular probes. Since then several outbreaks of rinderpest like diseases in sheep have been attributed to this virus. Cattle and pigs can have antibodies against PPR but do not come down with disease upon inoculation of PPR virus.
Epidemiology: The transmission of virus occurs through contact mainly through inhalation of aerosols produced by sneezing and coughing fomites; bedding may also contribute to the onset of an outbreak. Ocular, nasal, and oral secretions and feces are potent sources of virus. Infected animals can transmit the disease during the incubation period as well as during the recovery phase.
Clinical signs: Disease occurs in 2 forms; acute form which is common in goats especially in kids and subacute form which is common in sheep with mild clinical symptoms.The disease usually appears in an acute form, with an incubation period of 4 to 5 days followed by a rise in body temperature to 106° F (40-41° C). The temperature usually remains high for about 5 to 8 days before slowly returning to normal. Affected animals appear dull with a dry muzzle, and reduced appetite. From the onset of fever, mo st a nimals have a se rous na sal discha rge , which pr ogre ssively be comes mucopurulent. At this stage, animals suffer from respiratory distress, and there is sneezing in an attempt to clear the nose. The conjunctiva usually becomes congested and there may be profuse catarrhal conjunctivitis resulting in matting of the eyelids. Necrotic stomatitis is common. Death usually occurs after a course of 5 to 10 days. Bronchopneumonia, evidenced by coughing and characterized by consolidation, is a common feature in the later stages of PPR. Pregnant animals usually abort.
Diagnosis: Diagnosis is based upon clinical and necropsy findings supported by viral isolation in Vero and primary cells of ovine origin and characterization using RT- PCR to distinguish from rinderpest virus. Competitive ELISA based on monoclonal antibodies for detection of antigen is used.
Prevention and control: Vaccination; presently live attenuated tissue culture vaccine (Sungri 94 strain virus) produced by IVRI Mukteswar and from Anasur strain by TANUVAS are effective in controlling PPR in the country.