TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Emerging Diseases Of Marine Mammals Carol House USDA, APHIS, Foreign Animal Disease Diagnostics Laboratory PO Box 848, Greenport, NY 11944 Diseases "emerge" because of changes in the host, environment, agent, or better observation and testing. Newly isolated species of Brucella, a type of intracellular bacteria, have been implied in abortions of closely monitored dolphins. Many marine mammals (about 30% of those surveyed) have serological evidence of exposure to Brucella organisms, the significance of which has yet to be defined. The presence of Brucella in parasites may offer an explanation. Similarly, a number of marine mammals are known to be infected with herpesviruses, particularly under stressful conditions. Herpesviruses may not always cause illness, but may become a secondary factor in an immunocompromised or stressed individual. Papilloma viruses, the cause of some warts, have been observed in manatees and sea turtles, where they can cause blindness by growing on the eyelids. General skin lesions in sea lions can be caused by caliciviruses called San Miguel sea lion viruses. When these viruses are eaten by or injected into pigs, they cause vesicular disease called vesicular exanthema of swine, which is clinically indistinguishable from the dreaded foot-and-mouth disease. Since 1956, when uncooked marine products were not longer fed to pigs, this disease was declared eradicated from the U.S.A., despite the fact that new sea lion viruses continue to be described. Canine distemper virus, phocine distemper virus, porpoise morbillivirus, and dolphin morbillivirus (all related to human measles virus), can cause death in marine mammals. The stress of living in polluted waters appears to increase the mortality of animals infected with these viruses. Large die-offs from canine distemper in seals living in Lake Baikal, Russia, from phocine distemper in seals living in the North Sea and from dolphin and porpoise morbilliviruses in dolphins and porpoises living in the Mediterranean Sea have occurred. Phocine distemper and the dolphin/porpoise morbilliviruses infect many Atlantic marine mammals, but the North American coast has experienced fewer major catastrophic events due to these viruses. Recently, infection with dolphin morbillivirus has been described on the Pacific Coast of North America.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page