Natural distemper in vaccinated and unvaccinated dogs in Warsaw.

Two hundred and twenty-four dogs with clinical signs of distemper were examined for the presence of canine distemper virus (CDV) in mucous membranes by direct immunofluorescence assay. The study showed that 22% of the animals were CDV-positive. Most (33/50; 66%) of the infected dogs had never been vaccinated against distemper, whereas only 11 of 50 (22%) CDV-positive animals were immunized at least once. The difference in the infection rate between vaccinated and unvaccinated animals was statistically significant (P < 0.001), as assessed by the chi2 test. It is concluded that distemper is an important disease among dogs in Warsaw and the vaccination significantly reduces the risk of this disease.