Control of canine parvovirus infection in breeding kennels: Study of the efficacy of a high titer attenuated canine parvovirus vaccine

The aim of this study, which was conducted in two infected breeding kennels, is to assess the efficacy of a high titer attenuated canine parvovirus vaccine in 4- to 8-week-old pups and, in parallel, to determine the extent of the reduction in the critical period that this vaccine enables us to obtain. At the start of the intervention, the 126 pups in the two breeding kennels constituted a sensitive study population - 108 (85.71 %) had non-immunizing HI antibody titers (less than or equal to 64). A fortnight after a single injection with the vaccine, the rate of immunity was 91.27 % : 115 presented HI antibody titers greater than or equal to 128. The overall postvaccination seroconversion rate was 81.48 % for the 108 pups which had prevaccination titers of less than or equal to 64. The referential seroconversion rates of 95 %, 50 % and 0 % corresponded to HI antibody titers of < 32, 64 and <greater than or equal to> 128 respectively. With reference to traditional vaccines, these results enable the critical period to be reduced from 30 to 10 days, at a seroconversion rate of 95 %, and from 20 to 0 day(s), at a seroconversion rate of 50 %. The age groups to be vaccinated (4 to 8 weeks) correspond to the age groups most affected by a previous epizootic (6 to 8 weeks), with an anticipation period of 15 days (4 and 5 weeks). The pups, aged from 4 to 5 weeks old, which had HI antibody titers of less than or equal to 64 responded well to vaccination (vaccine efficacy 100 %).