Thousands of Caspian seals (Phoca caspica) died in the Caspian Sea from Apr
il to August 2000. Lesions characteristic of morbillivirus infection were f
ound in tissue specimens from dead seals. Canine distemper vi rus infection
was identified by serologic examination, reverse transcriptase-polymerase
chain reaction, and sequencing of selected P gene fragments. These results
implicate canine distemper virus infection as the primary cause of death.