Another phocine distemper outbreak in Europe.
Necropsies were performed on 8 harbour seals (Phoca vitulina) found dead at Anholt or on the nearby Danish mainland and from the Netherlands [date not given]. Lung, kidney, bladder and brain tissue samples were analysed for morbillivirus nucleic acid by reverse transcriptase-polymerase chain reaction (RT-PCR). Tissue samples from 3 Danish seals and a Dutch seal were positive and gave 429 base pair products. Phylogenetic analysis of selected fragments of the PCR products closely matched (>97% homology) those of phocine distemper virus (PDV) isolates from harbour seals in 1988 and were distinct from those of canine distemper virus (CDV) and other members of the genus Morbillivirus. Identical sequences obtained from Denmark and the Netherlands indicated that seals from widely separated regions of Northern Europe were infected by the same virus. Two adult Danish seals and the Dutch seal had IgM antibodies, showing recent PDV infection. These findings, together with the known severity of PDV infection in harbour seals, indicate that PDV infection is the cause of ongoing harbour seal mortality in Northern Europe.