Isolation and identification of peste des petits ruminants virus from goats in Egyptian governorates

The peste des petits ruminants (PPR) is a highly contagious disease of small ruminants which negatively affects animal production and the socioeconomic status of farmers. Peste des petits ruminants virus (PPRV) encodes eight proteins, with the viral fusion protein (F) playing a role in virus virulence and stimulating an effective protective immune response. This study aimed to isolate and complete the identification of PPRV circulating in goats in different Egyptian governorates and perform molecular characterization of the PPRV F gene.

Samples were collected from unvaccinated animals with clinical signs suggestive of PPR. A total of 256 sera were tested for the detection of PPRV antibodies using a competitive enzyme-linked immunosorbent assay (c-ELISA) kit, while 214 samples of blood buffy coat preparation, animal swabs (nasal, ocular, and saliva), and fecal and tissue samples were tested for the detection of the PPRV antigen using an antigen-capture ELISA kit. Molecular diagnosis, gene cloning, blast analysis, and phylogenetic analysis were performed for the molecular characterization of PPRV.

The seroprevalence results of PPRV antibodies in the tested sera showed a total of 67.9% positive samples. The rates of PPR antigen recorded by the antigen-capture ELISA in the swabs (nasal and ocular) and tissue samples were 44.3%, 46.8%, and 43.5%, respectively, with saliva swabs having the highest rate of PPRV positivity (76.4%) and fecal samples having the lowest (33.3%). Molecular characterization of the PPRV Vero cell culture revealed that the circulating PPRV strain belongs to the IV lineage. Blast analysis of the PPRV F gene showed 96.7% identity with the PPRV strain Egypt-2014 fusion protein (F) gene, KT006589.1, differing by 43 single-nucleotide polymorphisms.

The results of this study indicate that the emerging PPRV belongs to the IV lineage among small ruminant animals. The findings also indicate the need for an innovative strategy to control and eliminate this disease based on a regularly administered and effective vaccine, a test to distinguish between infected and vaccinated animals, and the need for further study on the protein structure and PPRV F gene expression, which should help us to understand the molecular evolution of the virus and control and eliminate PPR disease.