Development of an effective vaccine against foot-and-mouth disease with partially purified and concentrated virus antigen.

Foot-and-mouth disease (FMD) virus is poorly immunogenic. There is need to improve the quality of the vaccine by incorporating enhanced quantity of purified virus antigen to prevent sporadic breakdown of immunity in regularly vaccinated organized herds. A technique has been standardized for virus purification and concentration by polyethylene glycol (PEG) treatment for large scale production of concentrated FMD vaccine. The vaccine prepared with tenfold concentrated antigen was given field trial in an organised farm with a reduced dose as compared to the conventional vaccine. High level serum neutralizing antibody in cattle was observed throughout the entire period of study. The concentrated vaccine controlled the spread of the disease when used in face of outbreak in villages adjacent to the organized farm.