Efficacy of a commercial local trivalent Foot and Mouth Disease (FMD) vaccine against recently isolated O-EA3

Foot and Mouth Disease (FMD) is a highly infectious disease in clovenhoofed animals, the vaccination is widely used to control. Recently the FMDV topotype O-EA3 had been isolated that differs from the previous topotype Middle East-South Africa (ME-SA) with lineage Panasia2 (O Panasia2) that was prevalent in Egypt from 2010 to 2012. This study was designed to detect and characterize the recently circulating field isolate strain of FMDV in Egypt antigenically, and furthermore detect the efficacy of the existing local commercial vaccine against the recently isolated strain of FMDV. Five calves were vaccinated by local commercial inactivated FMDV vaccine; sera were obtained weekly till 28th day post vaccination and tested by SNT. The virulent circulating virus O-EA3 was isolated and full identified by AHRI while the propagation and titration in cattle tongue were carried out in CLEVB to adjust the challenge dose, then the challenge had been carried out for the vaccinated calves by local commercial vaccine at 28th day post vaccination. It was found that the SNT showed protective neutralizing serum antibody titer (1.2 log10) started from 3rd week post vaccination with 1,56 log10 titer against FMDV type O in vaccinated calves, while the challenge test showed that the protection level was 100% against O-EA3 in vaccinated calves with local commercial vaccine, Therefore, it appeared that the antigenicity of the type O viruses circulating in the region has not changed greatly, and the vaccines of Middle East origin (PanAsia2) can also be used against O-EA3 to control the disease, and there is no need to vaccine update.