الفهرس 
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Abstract
To investigate the current status of FMDv infection and to assure the vaccine efficacy used in some Egyptian governorates, a crosssectional survey was conducted between October2013 till July2014 in ten Egyptian Governorates (Cairo, Al-Qaliubia, Giza, Alexandia, Al-Behaira, Al-Gharbia, Kafer ElSheikh, Al-Fayoum, Al-Sharquia and Assiut). In this study >10,000 cattle and Buffaloes were studied, 529 serum samples out of them 321serum samples from nonvaccinated animals in FMD suspected foci and 208 serum samples from suspected free animals used for vaccinal Trials as well as 51 Saliva and tissue samples collected. The virus samples were serotyped by RTPCR and the complete VP1 coding regions in the PCR products of positive samples were sequenced .The results confirmed the presence of three serotypes [A (13.63%), O (56.81%), SAT2 (11.36%), A+ SAT-2 (2.27%)and A+O (2.27%)] of FMDv cocirculating in Egypt. Sequencing and phylogenetic analysis of VP1 further confirmed emergence of the East Africa3 topotype (EA3) of serotype O. Serotype O sequence was closely related to O/SUD/8/2008 with identity 93%, but differ from vaccinal strain (O/PanAsia2) of MESA topotype by 14.6%. Meanwhile Serotype A and SAT2 were closely related to recent Egyptian isolates and vaccinal strains type A/ EGY/1/2012 (Asia topotype, lineage Iran 2005) with identity 96.4% and vaccinal strain of SAT2/EGY/9/2012 (topotype VII, lineage SAT2/VII/Ghb12) with identity 92% respectively. Serum samples were screened against the three FMDV serotypes circulating in Egypt (A/EGY/1/2012, O/EGY/4/2012 and SAT2/EGY/9/2012) by using serum Neutralization Test (SNT). Results revealed that all three serotypes were circulating in all examined Governorates and the more prevalent serotype was SAT2 (64.1%) followed by serotype O (61.9%) and serotype A (55.8%). The period of the study indicated that serotype A was more prevalent from October to December, SAT2 more prevalent from January to May while serotype O started to increase from March till July. In relation to age, both cattle and buffalos less than 2 years old are more susceptible to FMD. Buffaloes showed high seropositivite than cattle to serotype A; however no significant differences between cattle and buffalos was observed in serotype O and SAT2. Vaccinal trial reviled that local vaccine has significant protection than imported for serotype O, however no significance in serotype A. on the other hand SAT-2 results were hard to explain as there was doubt about suspected FMD SAT-2 infection as the mean SNT titers for imported groups 1.77. The study concluded that there is species difference and age susceptibility to different FMDv serotypes in studied groups. Emerging of new topotypes of FMDv may require a change of vaccine production strategy. The present study recommended further studies for serotype O to confirm the immunogenic relationship between the vaccinal strain and the emerging new strains to provide maximum protection against circulating viruses.