Preparation And Evaluation Of Immune Effects Of The Bivalent Inactivated Vaccine Against Mink Pasteureilosis

Mink pasteurellosis is an acute, thermal resistance, septic infectious diseasescaused by pasteurella multocida and characterized by hemorrhagic septicemia andinfectious pneumonia mainly. The disease often occurs in spring and autumnseason.It is distributed and it is a local epidemic sometimes. Young minks were mostsensitive with high morbidity and mortality, causing serious economic losses in ourcountry. Therefore, it was very important for the prevention and cure of minkpasteurellosis to implement an popularity of pathogenic serotype study in some minkbreeding density area in our country. It was very difficult to prevent and treat minkpasteurellosis due to the multitudinous serotypes of pasteurella multocida and theresistance enhancement of it. There have yet no certificated vaccines for it. In orderto effectively prevent the mink pasteurellosis in our country, we successfullyseparated pathological materials of suspected mink pasteurellosis from Shandongarea and implemented the separation and identification of pathogen. We conductedserotype classification, drug sensitivity test and chose strong pathogenic, advantagepopular serotype strains. Then we completed the preparation and immunologicalefficacy on the bivalent inactivated vaccine against mink pasteurellosis.For the first step, pathogens from pathological materials collected fromShandong Province in2012-2013were isolated and identified28strains ofmink pasteurellosis were isolated from the total53pathological materialsof suspected Mink Pasteurellosis with a rate of52.8%. Serotyping for the isolatedstrains show that the pasteurella multocida type A with a rate of67.9%was the mainprevalent type followed by type B with the rate of32.1%. Moreover, most of theisolated strains were highly sensitive to doxycycline and amikacin following theantibiotic susceptibility testing.For the second step,4~6generations serotype A WF403strain and serotype BWF405strain were served as vaccine strains for the preparing the bivalent inactivated vaccine of mink pasteurellosis because of their causative force and stablebacterial content, virulence and immunogenicity after continuous batches. Twobatches of bivalent inactivated vaccine(2014615,2014624) were prepared byoptimizing the temperature and time of the vaccine strains culturing and qualified byPhysical properties testing, sterility testing, residues detection for thimerosal andformaldehyde and overdose security testing.Finally,the minimum immune dose and immune effect of the bivalentinactivated vaccine were detected. The results showed that the MID is0.25mL andthe routine immunization dose was1.0mL. The serum antibody levels of minkspeaked at14-21days after vaccination. The immune protection period of the bivalentinactivated vaccine was120days and it could be kept for9monthsat2-8℃. Resultsof clinical trials showed that the morbidity of minks inoculated with the bivalentinactivated vaccine just was0.041%, far bellowing that of non-immunized minksand predicating its good effect in the prevention of the mink pasteurellosis in ourcountry.This study developed an bivalent inactivated vaccine for epidemic serotype ofmink pasteurellosis, lying the theoretical and practical basis for preventing theoccurrence of mink pasteurellosis in our country.