MORBILLIVIRUS INFECTION IN BOTTLE-NOSED DOLPHINS - EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF-OF-MEXICO

Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottl enose dolphins, Tursiops truncatus, was first detected during an epizo otic along the mid-Atlantic tease in 1987. Here, we report recurrent e pizootics in the coastal dolphin population since at least the early 1 980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987-1988 and in the Gulf of Mexico between 1992 and 1994. Th is temporal pattern of infection is likely facilitated by the populati on size and its fragmentation into relatively discrete coastal communi ties. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizoot ic along the cease is probably determined by frequency of contact betw een adjacent communities and seasonal migrations. Morbillivirus antibo dies were also detected in serum from offshore bottle-nose dolphins. T he sere-prevalence in the latter may be higher than in coastal dolphin s because of their close association with enzootically infected pilot whales (Globicephala spp.). Occasional contact between offshore and co astal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities.