Some epidemic characteristics and typing of FMD virus in Lang Son province from 2011 to 2015

Abstract

From 2011 to 2015, in Lang Son province, Viet Nam, foot and mouth disease (FMD) occurredin 11 districts and town. On average, 1.26% of the buffaloes and cattle were infected with FMD per year. Of which, the infection rate of buffaloes was 1.39% and cattle was 0.75%. In 2011, the infection rate of buffaloes and cattle was highest (5.3%). The main source of FMDV was from the infected buffaloes and cattle, which were recovered from treatment, without clinicalsymptoms of FMD, but in fact the animals still carried FMDV and discharged FMDV to the environment. On average, the natural infection rate of the buffaloes and cattle in Lang Son was 33.23%. Of which, the highest infection rate was in the following districts: Bac Son (66.66%), Van Quan (50%), Trang Dinh (32.88%) and Binh Gia (28.57%).The FMD virus strains were isolated from the buffaloes and cattle in Lang Son province belonging to type O and type A. While FMD virus belonging to type Asia 1 was not found in Lang Son province. Thus, the suitable vaccine for the buffaloes and cattle in Lang Son province would be Aftovax Bivalent, with 2 types of O and A.After injection with FMD vaccine, 100% of the buffaloes and cattle presented immune response.30 days after vaccination, the rate of protection varied from 86.6% to 100%. Six months after the first vaccination, the second vaccination dose should be injected for assurance of FMD prevention in buffalo and cattle