Molecular and serological typing of foot-and-mouth disease virus serotypes currently circulating in Egypt

Foot-and-mouth disease (FMD) is an extremely contagious viral disease affects all cloven- hoofed animals. The present study aimed to investigate the epidemiological situation of FMD in Egypt during 2017 and 2018, based on antigenic and genetic characterizations of FMD virus (FMDV). Thirty oral epithelia were collected from vaccinated animals (14 native cattle and 16 water buffaloes) showed clinical signs of FMD in four Egyptian governorates having outbreaks. In all collected samples the antigen detection was performed using enzyme-linked immunosorbent assay (ELISA), while the genetic characterization was done by using conventional reverse transcription polymerase chain reaction (RT-PCR), Sequencing and phylogenetic analysis were constructed for genetic characterization. The obtained results of FMDV antigen detection ELISA indicated that 50% of the examined samples were positive for FMDV and serotyped as serotype O 40%, serotype SAT2 33% and serotype A 27% respectively. RT-PCR confirmed the results of FMDV antigen detection by ELISA. Six amplicons were sequenced and phylogenetically analyzed for viral protein 1 (VP1) of FMD. Results demonstrated that genotype O was related to East Africa-3 (EA-3) topotype with 12.7% difference from vaccine strain O-IRN-8-2005-Pan-Asia-2. Furthermore, genotype A clustered into Asia topotype with 6% difference from vaccine strain A-IRN-1-2005. Meanwhile genotype SAT2 in 2018 was related to VII topotype but it was in close relation with strains isolated from Libya in 2012 with 94.3% amino acid identity that differ from the previously circulated SAT2 since 2012 and recorded recently in Egypt. The presented results confirmed the circulation of a new topotype of serotype SAT2.