A New Pen Side Diagnostic Kit for Simultaneous Detection of Antibodies to Different Serotypes of Foot and Mouth Disease Virus in Sera

A field applicable kit for easily identifying the serotype of the pathogen causing infection in an area enables targeted vaccination against the prevalent serotypes only avoiding non prevalent serotypes.We have developed a multiplex agglutination based cheap and simple prototype pen side kit to differentiate serum antibodies against different serotypes of Foot and Mouth Disease (FMD) virus employing inactivated FMDV of serotypes O, A and Asia-1 conjugated with latex beads/microspheres of different colors.The kit was used for detection of antibodies in sera from 142 cattle and buffaloes.Antibodies could be detected against all the three serotypes in the sera of 133/142 (93.66%) of the animals.However, antibodies against A serotype could not be detected in the serum of 1 (0.7%) animal, and against Asia-1 serotype in the sera of 2 (1.40%) animals, respectively.Four (2.80%) serum samples were double negative for O and Asia-1 serotypes and one (0.7%) sample each was double negative for O and A as well as A and Asia-1 serotypes, respectively.Antiglobulin was used to enhance the sensitivity of the kit through cross-linking of smaller clumps.Detection of antibodies to FMDV A was then possible in the sera of all the three previously negative animals.Except 2 / 5 and 1 /7 sera which were still negative for FMDV O and Asia-1, respectively, all the previously negative sera gave positive reaction on addition of antiglobulin.The results were confirmed with LPB ELISA.Thus, antiglobulin aided multiplex agglutination may be more sensitive minimizing false negative results.