Research On Foot And Mouth Disease Virus Type O (myanmar’s98) Virus Strains Screening And Inactivated Vaccine Immunization Effect

Foot-and-Mouth Disease (FMD) is an acute, highly communicable and economicallyimportant disease caused by Foot-and-Mouth Disease virus (FMDV). FMD has been one ofthe most important diseases causing significant economic losses in livestock. We shouldscreen a candidate vaccine strains，it will play a very important role to effective control of theepidemic.This thesis is dealt against that Chinese Academy of Agricultural SciencesFoot-and-Mouth Disease reference laboratory isolated and identificated four（SEA Topotype）MYA/98type O FMD virus. We carried out neonate rat passaged in the laboratory, cells ofsquare bottle passaged domestication, passaged cells adaptation of transfected flasks in theproduction workshop and evaluation of vaccine production. Based on the above three stagesduring the best time for virus harvest., virus content, the adaptation of the target animal andthe target cells, we selected a stable passaged virus for the virus content of higher levels ofvaccine strains-O/XJ/10-11strains. After subculture, three batch of venom were harvestedand inactivated processing respectively according to the technical process，made intoinactivated vaccines（during we had the finished product of inactivated effect inspection,properties inspection, safety inspection.）. With the existing classical OZK/93strains producedthree batches of vaccines, and immunizated susceptible animals by screening pigs, rearedunder the same conditions,28days after vaccination compared the test pig serum antibodytiters, and conducted cross-attack vaccine protection test, a preliminary assessment of the twovaccines immunity. The results showed that two kinds of vaccinations immunizatedanimals,they can stimulate the body to produce higher antibody levels,which immunizedgroup pig (inactivated vaccine of S01batch O/XJ/10-11strains)of antibody titers <1:4accounted for10%;1:4to1:45accounted for65%,≥1:64accounted for25%; control groupimmunized inactivated vaccine of OZK/93strains.(1) Immunized group pig of antibody titers1:4accounted for5%,1:4to1:45accounted for60%,≥1:64accounted for35%; immunizedgroup pig (inactivated vaccine of S02batch O/XJ/10-11strains)of antibody titers <1:4accounted for15%1:4to1:45accounted for45%,≥1:64accounted for40%; control groupimmunized inactivated vaccine of OZK/93strains.(2) Immunized group pig of antibody titers <1:4accounted for15%,1:4to1:45accounted for80%,≥1:64accounted for5%; immunizedgroup pig (inactivated vaccine of S03batch O/XJ/10-11strains)of antibody titers <1:4accounted for10%,1:4to1:45accounted for35%,≥1:64accounted for55%; control groupimmunized inactivated vaccine of OZK/93strains.(3) Immunized group pig of antibodytiters <1:4accounted for0,1:4to1:45accounted for50%,≥1:64accounted for50%.Homologous strains and OZK/93strains were challenged the immunized pigs (Inactivatedvaccine of O/XJ/10-11strains), the immunity protection rate against strong virus was80%ormore; OZK/93strains were challenged the immunized pigs (Inactivated vaccine of OZK/93strains), the immunity protection rate against strong virus was80%or more; but O/XJ/10-11strains were challenged the immunized pigs (Inactivated vaccine of OZK/93strains), theimmunity protection rate against strong virus was60%. The analysis showed that there werethe same immune effect between immunized group pig (inactivated vaccine of O/XJ/10-11strains) and immunized group pig (inactivated vaccine of OZK/93strains)with the sameimmunizing dose preconditions under certain circumstances, the cross-protection ofinactivated vaccine of O/XJ/10-11strains appeared higher than that of nactivated vaccine ofOZK/93strains.In summary, the（SEA Topotype）MYA/98type O FMD virus strains can replace theclassic OZK/93type O FMD virus strains for vaccine production.