Antibodies against canine parvovirus in wolves of Minnesota: a serologic study from 1975 through 1985

Serum samples (n = 137) from 47 wild wolves (Canis lupus; 21 pups and 26 adults) were evaluated from 1975 to 1985 for antibodies against canine parvovirus, using the hemagglutination inhibition (HI) test. In addition, several blood samples (n = 35) from 14 of these wolves (6 pups and 8 adults) were evaluated simultaneously for erythrocyte and leukocyte counts, and for hemoglobin and blood urea nitrogen concentrations. Sixty-nine (50%) of the serum samples (35 wolves) had HI titers of greater than or equal to 256, whereas 68 (50%) of the samples (16 wolves) had HI titers of less than or equal to 128. Significant differences in the geometric mean titers were not found between pups and adults or between males and females. Of the 47 wolves evaluated, 12 (25%) developed a greater than or equal to fourfold increase in antibody titers during the 11-year period, with 2 wolves developing serologic conversions in 1976. The data indicate that canine parvovirus may have begun infecting wolves before or at the same time that it began infecting the dog population in the United States.