Preparation And Effect Of Canine Parvovirus Enteritis Vaccine

Canine parvovirus(CPV) enteritis are prevalent in all over the world and suffered high morbidity and mortality, resulting in dog and pet industry economic losses, which also has a great impact on the survival of wild animals. At present, effective treatment strategy has not been found. Vaccine development is the key to prevent the infection of CPV. Because the antigen of CPV is easy to change, the development of vaccine must base on the CPV epidemic and antigen specificity.CPV-S5(New cpv-2a gene subtype) and CPV-1401(New cpv-2b gene subtype) strains were cultured in F81 cells, which were isolated and preserved in lab recently and the optimal. Culture conditions were determined. The cell culture fluid was concentrated by two kinds of concentration methods that high concentration salt concentration and small tangential flow ultrafiltration concentration. The virus was inactivated by adding a final concentration of 0.05% BPL and place at 4? for 24 hours, and then 37? hydrolysis of 2h. The virus fluid was mixed with water adjuvant MONTANIDE GEL as 1:9 ratio. The result showed that the three batches of vaccine were inactivated successfully, sterile identification of negative, and the appearance of transparent without turbidity, the dogs showed no obvious clinical side effects and effective specific immune response post-immune, indicating that CPV vaccine was successfully prepared.5 weeks old puppies without CPV HI antibody were immunized by the first batch of inactivated vaccine and commercialization of canine parvovirus attenuated vaccine.At 0, 7, 14, 21, 28 d the blood were collected and the antibody titers were detected by HI test. The results suggested that all the immuned group at 7d can produce higher than HI antibody titer of 1:80, and the concentrated groups was significantly higher than that of non-concentrated groups, which indicated that the effect of CPV inactivated vaccine was directly related to the concentration of antigen. Inactivated vaccine group and commodity attenuated virus vaccine group were significantly different. The group of canines immunized for 36 d of canine were challenged with virulent CPV and showed no obvious clinical symptoms within 20 days, in which only two of canines produced slight symptoms but eventually tolerance, but the negative control canine died. The challenge experiment shows that the CPV inactivated vaccine could induce the dogs to resist the virulent attack.The undead dogs after challenge were immunized secondly with another batch of inactivated vaccine. The results showed that the dogs had no CPV in their feces and mean serum HI titer was 1:3072.In order to further evaluate the effect of the vaccine, 3-month-old CPV negative Beagles were immunized with the inactivated CPV and their HI titers were detected after immunization 7, 14, 21 and 28 d. The results indicated that HI antibody titers at 7d was 1: 448. The general trend of antibody dynamics was the same as the first concentrated CPV-S5 inactivated vaccine group. It suggests that the immune effect of inactivated vaccine was more stable repeatability, and further demonstrates its immune effect is directly related to the concentration of antigen.