Foot-and-mouth disease virus isolates: Candidate strains for trivalent vaccine development in Nigeria

A quality foot and mouth disease (FMD) vaccine is a prerequisite for effective control in addition to other zoosanitary measures and effective biosecurity practices in disease endemic sub-Saharan countries like Nigeria. To ensure an effective control programme by vaccination, countries that practice mass vaccination campaigns need to conduct vaccine matching studies to establish a relationship between prevalent field isolates with available vaccine for effective control. To this effect, a research was conducted in order to select foot-and-mouth disease viruses (FMDV) that will give a quality vaccine containing relevant serotypes and matching strains as a pre-requisite for effective vaccine. The study was conducted using two dimensional virus neutralization assays to determine the antigenic relationship ‘r’ value between the candidate vaccine strains and the field isolates. A total of forty-two specimens (epithelial tissue) were send to the World Reference Laboratory for Foot-and-Mouth Disease (WRLFMD) for virus detection and antigen serotyping and some of the field isolates were selected for vaccine matching based on geographic location and topotypes/subtype. The isolates selected were two each of serotype O, A and SAT 2 from bovine species. The selected field isolates revealed high antigenic similarity with the vaccine strains tested showing ‘r’ value greater than 0.3 which suggests a close relationship between field isolates and vaccine strain tested. A potent vaccine containing the vaccine strain is likely to confer protection in vaccinated candidates. A vaccine match with ‘r’ value less than 0.3 suggests poor protection against challenge with the isolates. The result of this study has indicated that the selected field isolates could be used as vaccine strains for a candidate trivalent FMD vaccine production in Nigeria.