FIG. 1.

Mean reciprocal IFA titer results for serum samples from experimentally vaccinated animals. IFA results are shown for serum specimens collected throughout the study. Reciprocal IFA titers are given for the mean obtained from three dogs in each vaccine group. The IFA titer was <100 for serum samples from the single unvaccinated control dog at all time points. Dogs were vaccinated at weeks 0, 2, 33, 36, and 39 as described in Materials and Methods. Serum samples were obtained prior to vaccination at weeks 0 and 33. Vaccine manufacturers were Fort Dodge, Schering-Plough, and Merial.