Preparation Of Type O Bovine Foot And Mouth Disease High Concentrated Inactivated Vaccine

Foot and Mouth Disease (FMD), a major threat to cloven-hoofed animals such as bovine, swine and sheep, is a highly contagious disease caused by Foot and Mouth Disease Virus (FMDV). Since it has a high incidence and can easily cause an epidemic outbreak and enormous loss of economy, Office International des Epizooties (OIE) ranks it in the first in all contagious diseases for domestic animals. The governments of countries all over the world have focused much attention on the prevention and control of this disease.Since vaccination was one of major means to prevent domestic animals from this disease, many countries paid much attention to the development of FMDV vaccines for almost a century in order to prevent and control the outbreak and prevalence of FMD.Thus far, the means mainly adopted in China to prevent domestic animals from the infection of FMDV is the use of the crude, non-concentrated preparation from the viral culture prior to chemical inactivation. In general, the guideline of a FMDV vaccine requires that 3 milliliters per dose per animal contain 3 PD₅₀ or that the protection rate after the viral challenge should reach at 4 protected out of 5 tested animals or greater. Since the concentration of viral antigens in the non-concentrated crude viral preparation is relatively low and it contains a trace amount of nonantigenic proteins from the host cell debris, this makes the vaccines usually in a weak protection, a relatively short duration for immune response and side-effects.The purpose of this study is to, through a series of means including a concentration process of the FMDV antigens, produce a higher standard vaccine to meet the international criteria and subsequently scale up the production, thus exploring a set of new technologies for the production. The aim of such new vaccine mainly focuses on improving the efficacy of the present vaccine and achieving the criteria as follows:1. The increasing of the safety: The inoculation of the vaccine is safer to animals with minimal side-effects.2. The reduction of the volume per dose: Each dose of the vaccine is 2 milliliters per animal instead of 3 milliliters from the pre-improved vaccine.3. The improvement of the efficacy: Each dose of the vaccine contains more than 6 PD₅₀, rather than 3 PD₅₀ from the pre-improved vaccines.4. The longer duration of the immune response: The vaccine can improve the duration from 4 to 4.5 months to 6 to 7 months.Through examining the biological characteristics of the vaccine strain especially for its the virulence and immunogenecity, evaluating the pre-process for the viral culture and the concentration technology, establishing the testing standard protocol for the viral antigen content after concentration (the results from the established new testing protocol obtained from ELISA and TCID₅₀ were consistent with the results obtained from the suckling mouse LD₅₀ protocol), using international standard to determine the PD₅₀ and comparing the efficacy with the pre-improved vaccines, three batches of tested vaccines all met every preset criterion in both laboratory and field test with a 100% success. To date, this vaccine has been passed the assessment and evaluation by the Ministry of Agriculture of the People's Republic of China and will be certificated for the license soon.