Foot-and-mouth Disease Virus type (O) Overhangs Livestock Industry of both Young and Adult Cattle and Buffalo in Egypt

Egyptian farms is still attacked by several outbreaks of FMDV, a highly contagious viral disease that threatens the livestock industry worldwide. Many of these outbreaks are unreported. Hence, the epidemiological situation and molecular characterization of the currently responsible strains of recent FMD outbreaks are missed. To identify FMDV strains currently circulating in cattle herds and catch the recent update in the morphophonological changes due to that virus, we carried out this study on the FMD outbreak from 2016–2017 in Egypt. Clinical samples (post mortem tissues samples, oral swabs, epithelial suspensions from ruptured vesicles, and blood) were collected from clinically examined animals suspected to be of being FMD virus = 229 cattle and 138 buffalo. Of 175, 96 (54.8%) samples and 85 (44.3%) from 192 samples were positive in 2016 and 2017, respectively. Pathological examination revealed the classical lesions of FMDV as vesicular and erosive lesions on cornified epithelial tissues. Multi-focal areas of lympho-plasmocytic myocarditis were seen in the heart of all calves. Similar lesions were also observed in the heart of adult cattle that died in that outbreaks. Detailed pathological alterations in adult and young animals were described. Polymerase chain reaction (PCR) screening of tissue specimens using specific primers for FMDV was done. Serotype O was the only serotype that was detected in our study and submitted in the Genebank. The four field isolates of serotype O that have been submitted in the Genebank had been found to belong to the EA-3 topotype. Nucleotide sequencing of the VP1 region and phylogenetic analysis has been used to determine the relationships between our field isolates, other recently isolated Egyptian isolates, and other isolates from some African countries and vaccinal strain used for serotype O in Egypt. The presence of strains of increased virulence among cattle and buffalo in Egypt could be attributed to the introduction of new viral strains through uncontrolled transboundary movements of animals during the last public revolution in Egypt in 2011.