STUDIES ON MANIFESTATIONS OF CANINE-DISTEMPER VIRUS-INFECTION IN AN URBAN DOG-POPULATION

An upsurge of canine distemper was recognized at the beginning of 1991 in the urban dog population of the Copenhagen area. The outbreak had the characteristics of a virulent morbillivirus introduction in a part ly immune population, where the disease primarily was manifested in yo ung individuals. Testing of single serum samples for the presence of c anine distemper Virus (CDV) IgM antibodies using an IgM ELISA confirme d current and recent CDV infections in an urban dog population, where the use of attenuated CDV vaccines was widespread. In 49 out of 66 ser a from clinical cases suspected of canine distemper we detected CDV Ig M antibodies, as compared to the detection of viral antigen by indirec t immunofluorescence in 27 of 65 specimens of conjunctival cells. The antigenic make-up of isolates from acute and subacute clinical cases w as investigated with a panel of 51 monoclonal antibodies directed agai nst CDV and the related phocine distemper virus. The isolates exhibite d an homogenous reaction pattern and shared overall antigenic characte ristics of the CDV prototype. The majority of cases were diagnosed amo ng unvaccinated dogs and individuals with unknown or obscure vaccinati on record. However, severe clinical cases were also diagnosed in vacci nated individuals.