Enzyme linked immunosorbent assays (ELISAs) have been developed for the detection of antibodies against contagious caprine pleuropneumonia (CCPP), the causative agent of which is Mycoplasma capricolum subsp. Capripneumoniae (Mccp). The currently available commercial CCPP competitive ELISA (CCPP cELISA) kit produced and supplied by IDEXX Company (Westbrook, Maine, United States) is relatively expensive for most African laboratories. To address this issue and provide a variety of choices, a sensitive and specific blocking-ELISA (b-ELISA) test to detect antibodies against CCPP was developed. We describe the newly developed CCPP blocking-ELISA based on the blocking of an epitope of a monoclonal antibody (Mccp-25) by a positive serum sample against the Mccp protein coated on a plate. The Percentage Inhibition (PI) cut-off value for the CCPP b-ELISA was set at 50 using 466 CCPP negative and 84 CCPP positive small ruminant sera. Of the negative sera, 307 were obtained from the Botswana National Veterinary Laboratory (BNVL) and 159 from the Friedrich-Loeffler-Institute (FLI) Germany. The 84 positive sera samples came from experimentally vaccinated goats at the AU-PANVAC facility in Debre-Zeit, Ethiopia. The relative diagnostic sensitivity and specificity of the CCPP b-ELISA was 93% and 88%, respectively. This test result indicated good correlation with that of the commercial CCPP cELISA by IDEXX Company (Westbrook, Maine, United States) with a Cohen’s κ agreement of κ agreement of 0.85. The newly developed CCPP b-ELISA will be useful in the detection of antibodies for the diagnosis CCPP and for sero-surveillance during vaccination campaigns.

Summary: PPR is a common and dreadful disease of sheep and goats in tropical regions caused by PPRV which can infect also cattle without any clinical signs but show a seroconversion. However the epidemiological role of cattle in the maintenance and spread of the disease is not known. For the purpose of the present study, cattle were infected with a wild candidate from each of the four lineages of PPRV and placed in separate boxes. Then naive goats were introduced in each specific box for the 30 days duration of the experiment. The results showed that no clinical signs of PPR were recorded from these infected cattle along with the in-contact goats. The nasal and oral swabs remainend negative. However, animals infected with wild types of PPRV from lineages 1, 3, 4 seroconverted with high percentage inhibition (PI %= values. Only two animals out of three with the Nigeria 75/3 strain of lineage 2 (mild strain) did elicit a production of specific anti-PPR antibodies in those cattle but with PI% values around the threshold of the test. Our findings confirm that cattle are dead end hosts for PPRV and do not play an epidemiological role in the maintenance and spread of PPRV. In a PPR surveillance programme, cattle can serve as indicators of PPRV infection. Importance: Peste-ds-ptetis-ruminants (PPR) is a major Transboundary Animal disease (TADs) in the tropical regions which is spreading extensively nowadays to southern and northern of Africa, Turkey in Europ and southwest Asia. PPR virus is very close related to Rinderpest virus (RPV) which has been eradicated from the world. Today FAO, WOAH / OIE and the scientific community have elected PPR to be the second animal disease to be eradicated through The PPR Global Eradication Programme (GEP-PPR). Since PPR infects cattle without any clinical signs but they seroconvert, it is important to explore the role of cattle in the maintenance and spread of PPRV to better understand the epidemiology of the disease which wll help in the the GEP-PPR.