TO THE CANINE-DISTEMPER SITUATION IN GERMANY

Outbreaks of canine distemper occur even in countries with a high vacc ination rate. Therefore it may be discussed whether the canine distemp er virus (CDV) vaccines in use would infer proper protection against C DV or not. Since they are derived from CDV strains in the 1950s, it is speculated that recent field isolates might be genetically and thus a ntigenically different. We here report about results of the analysis o f the genes coding for the immunologically relevant virus surface glyc oproteins H and F of recent field isolates. It turned out that recent viruses were not different from ''classical'' CDV. Although they were genetically distinguishable from the conventional vaccine strains comp arative neutralization assays did not reveal any significant differenc es. The phylogenetic analyses (H and F genes) confirmed the close rela tionship of recent isolates but also showed that more than one CDV gen otype is circulating. Furthermore, there were hints at a mustelid line age of CDV. The consequences of these results upon epidemiology and pr ophylaxis of CDV infection are dicussed.