Dr. Samson Leta. Dr. Haileleul NegussieBezawit Tesfaye2025-08-022025-08-022025https://etd.aau.edu.et/handle/123456789/5899Peste des petits ruminants (PPR), sheeppox (SP) and goatpox (GP) are economically important diseases in Ethiopia. These diseases are commonly distributed throughout Ethiopia, hindering productivity and leading to substantial economic losses. Given Ethiopia's ambitious goal to eradicate PPR by 2027, this research aimed to develop and evaluate the efficacy of a combined vaccine by starting with the preparation of monovalent PPR and SP/GP live attenuated vaccines separately using Vero cell culture and with the determined titer 4.8 log10 TCID50 per ml and 4.6 log10 TCID50 per ml respectively, before being combined. Quality control tests, including sterility, moisture content, and safety in guinea pigs, were performed. A total of 10 sheep and goats were immunized, and their immune responses were monitored through daily body temperature readings that was maintained in the normal range between 37.38oC-39.32oC, C- ELISA test result for antibody detection of PPR read its peak on 10.59% for group A and 10.58% for group B, while Group C remained with no antibody, heightened that Group A and B animals confers protection up on natural infection. The SNT test results also revealed that vaccinated animals in each group had strong antibody titers against SP/GP, defined as values greater than 1.5 log10. Each of these animals challenged by PPR and GP viruses isolated on Verodog-SLAM for PPRV and on Vero and ESH-L cells for GPV. Finally, the challenge experiment discloses that vaccinated animals stayed in their normal behavior while control animals unequivocally manifested disease-specific clinical signs, which was confirmed by molecular detection of nucleic acids of both viruses. These findings underscore the vaccine's robust efficacy in preventing overt disease and secured immunogenicity of both vaccines. Further researches on the deployment of this live attenuated combined vaccine on a field basis have of utmost importance to completely asses its efficacy and effectiveness.en-USAntibody titerscombined vaccinechallenge testefficacygoat poxpeste des petits ruminantsquality controlSheep poxThesis