Biological Assay of Foot and Mouth Disease Virus (FMDV) Serotypes for Titrating BLRI Developed Trivalent FMD Vaccines Seed

Foot and Mouth Disease (FMD) is an important viral as well as transboundary disease affecting almost all cloven-hoofed animals. The aim of the present study is the focused on determination of biological titer by tissue culture infective dose 50 (TCID 50 ) assay of currently available FMD virus serotype in Bangladesh. For adaptation of FMD virus (FMDV), BHK-21 cell line was used. BHK-21 cell subculture was done from preserved cultured bottle of Foot and Mouth Disease (FMD) Research Laboratory of Bangladesh Livestock Research Institute (BLRI), Savar, Dhaka. RT-PCR confirmed selected three different positive serotypes (O, A and Asia 1) of FMD virus were inoculated into BHK-21 cell culture and cytopathic effects (CPE) were observed after adaptation into BHK-21 cell from 3 rd to 5 th passages. Clear infectious BHK-21 cell culture fluid was collected and preserved at -80℃ temperature. The TCID 50 assay was performed to determine the biological titer of the three positive serotype of FMDV. The biological titer of this study was found 10 6.5 /ml viral titer for O type, 10 6.75 /ml viral titer for A type, 10 6.66 /ml viral titer for Asia-1 type. These three specific serotypes can be used as vaccine seed against FMD virus. The effective vaccination of susceptible animals is considered to be the corner stone to the disease in our country Bangladesh. The findings of this study can be helpful for the trivalent vaccine development in Bangladesh and it may effective in limiting the spread of FMD.