الفهرس 
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Abstract
The present study was aimed to investigate the epidemiological situation of FMD in Egypt from 2016 to 2018 based on determination of antibodies against NSP, implementation a pilot study on circulating FMDV serotypes, assure the efficacy of locally produced inactivated trivalent vaccine. A total of 1500 sera were collected from apparent healthy vaccinated cattle and buffaloes from three Egyptian geographical sectors, representing ten governorates. Determination of FMD antibodies against NSP was carried out using prioCHECK 3ABC ELISA test. Serotyping of the circulating FMDV and assure the vaccine efficacy was performed using ELISA. The 3ABC ELISA test revealed 26.4% and 23.7% positive for FMDV-NSP antibodies in cattle and buffalo sera, respectively. The highest positivity was in Delta Sector among both cattle 42.3% and buffaloes 28.8%. Serotyping of FMDV positive NSP sera in El-Qalyubia governorate for the circulating FMDV serotypes O, A, and SAT2 was 52.2, 17.4, and 30.4% in cattle and 31.8, 27.3, and 40.9% in buffaloes, respectively. The overall protection level due to the vaccination program was 62.1 and 60.9% in cattle and buffaloes, respectively, while the protective level of the FMDV serotypes O, A, and SAT2 included in the inactivated trivalent vaccine was 73.9, 84.6, and 63.8% in cattle and 72.3, 82.3, and 63.5% in buffaloes, respectively. 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 ELISA, while the genetic characterization was done by using conventional 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 with12.7% 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. Therefore, further studies are recommended to evaluate the cross protection between the vaccine strains and circulating strains in the field.