Evaluation of the Serological Response after Foot-and-Mouth Disease Vaccination in Pakistan

Abstract

Among viral diseases, foot and mouth disease (FMD) is a highly contagious, economically important disease of cloven-hoofed animals caused by a virus of the genus Aphthovirus, family Picornaviridae. A total of 12 calves of about one year old with proper tags were selected for the study. These animals were divided into four groups i.e A, B, C and D (each having 3 animals) and Group C as a control group having 3 animals (including two positive C1 and one negative control animals C2). Group D having 3 animals were named a challenged group as these animals after priming dose were exposed to live virus. Blood samples from animals of all groups were collected on day zero. On day zero, 3 groups (A, B & D) were vaccinated with 3ml Foot and Mouth Disease Research Laboratory (FMDRL) Trivalent Foot and Mouth Disease Vaccine (Oil-based) simultaneously. On the 28th day of Priming dose, Group A was given a booster dose, while Group D, along with a positive control C1, were challenged with live virus. Group B was reared with a priming dose only. Group D, along with the positive control, were examined for the next 10 days for any pathognomonic signs related to FMD. In clinically positive case the signs developed and the animals were tested for the FMD virus. Antibody titer of all the groups was checked through enzyme linked immune sorbent assay (ELISA) on the 28th day and then after every 30 days for 12 months. The protection provided by the “O”, “A”, and “Asia-1” serotypes in the vaccine on the priming dose was 10, 6, and 6 months, respectively. Similarly, the protective titer provided by the “O”, “A”, and Asia-1 serotypes in the vaccine on the boosting dose was 13, 13, and 12 months, respectively. The antibody titers provided by the animals of group D (with infection) were 10, 8, and 8 months for O, A, and Asia-1. From the present study, it is concluded and recommended that the FMDRL vaccine is collectively effective and provides a protective titer against all serotypes for at least 6 months on a single dose. However, further studies may be conducted to elucidate the protection provided by the vaccine.