1604: Antibody Response and Duration of Immunity in Dogs Vaccinated with Attenuated Canine Distemper Virus, Canine Adenovirus Type 2 and Canine Parvovirus Vaccines from Commercial Sources
Grant Status: Closed
Project SummaryAnnual revaccination of dogs with a combination canine distemper virus, canine adenovirus type 2 and canine parvovirus vaccine is routine although there is no scientific documentation to support the practice. If annual revaccination is not essential for the prevention of these infectious diseases, risk of vaccine-associated side effects could be avoided. Based on evidence that current vaccines may provide long-term protection, the researchers hypothesized vaccines against canine distemper virus (CDV), canine adenovirus (CAV-2), and canine parvovirus (CPV-2b) provide protection for 3 years or longer. The proposed study was performed for the 2-fold purpose of determining the minimal number of doses of vaccine necessary to immunize puppies and maintain protection in adulthood. Blood for assay of antibody levels was collected by jugular venipuncture from healthy dogs and puppies and analyzed by standard assays to determine antibody level. Puppies and adult dogs with CDV, CAV-2 and CPV virus neutralization titers equal to or greater than 1:50, 1:,1 00, and 1:50, respectively were considered to have acceptable titers and did not require revaccination. The quantity of antibody essential for protection against these viruses during challenge studies has been previously reported using these standard assays. That information was used to determine the criterion for acceptable antibody levels for imrnunization and protection. Assays for antibody in blood serum were performed prior to vaccination in puppies and again after a 2 vaccine series performed in 2-3 week intervals. Assays or antibodies were taken on dogs prior to entry into study. Puppies and dogs with acceptable antibody titers required no additional vaccines. Additional vaccines were administered as necessary to sustain immunity. All dogs requiring vaccination were given an attenuated vaccine that was selected on a rotating basis. All dogs were tested annually for 3 consecutive years. Immunity was measured using standard assays and the data was statistically analyzed using chi-square and repeated rneasures analysis of variance. During the study there was a loss of 83% puppies and 16% of adult dogs. Eighty-four percent puppies had non-acceptable titers prior to vaccination. Of the puppies that completed the vaccine series, 93% developed acceptable titers after 2 doses of as-antigen vaccine combination given 2-3 weeks apart. The number of dogs with acceptable antibody titers varied between the adult dog groups in which group 4 (lBDS) dogs were highest and group 3 (Foxhounds) lowest in all 3 years of the study. Group 3 had the highest number of animals that required booster vaccinations for CDV and CPV for all years except year 0 when compared to the puppies before vaccination. However these differences in frequency of vaccination were only significant in comparison to group 4 in year 0 for all three vaccine antiqens. Of the dogs that completed the study, the percentage of dogs that had acceptable antibody titers for CAV-2, CDV, and CPV-2b was 86% for 1 year, 73% for 2 years, 50% for all 3 years of the study. Therefore it is the researchers recommendation that dogs receive vaccination for CAV-2, CDV, and CPV-2b every 2 years.
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