A Descriptive Epidemiological Study of Stranded Dolphins Along the Florida Coastline

A collaborative project examined the disease status of dolphins that stranded along the coastline of Florida from 1996 to 2002. This study reviewed 68 freshly dead stranded dolphins (57 Tursiops truncatus and 11 others from four species). Analysis of stranding demographics and histopathologic data from the Southeastern United States Stranding Network provided important information on the prevalence of lesions in relation to sex, geographic location, season, and length in T. truncatus. The histopathologic results obtained from the other species were from an extremely small sample size and thus only provided limited insight into the diseases impacting them. Cardiomyocyte degeneration and lymphoid depletion were found in all five species examined. Some of the pathologic findings found in \u3e20% of the T. truncatus tissues examined included pneumonitis, pulmonary fibrosis, edema, angiomatosis, nematodiasis, hepatic fibrosis, hepatocellular atrophy, glomerulonephritis, cardiomyocyte degeneration, cardiac fibrosis, lymphoid depletion, lymphadenitis, lipid depletion, gastritis, and enteritis. There were no trends seen in the histopathologic data related to sex, geographic area, or season. There were however differences in the prevalence of some lesions in relation to length class in the lung, spleen, kidney, and heart. There was a significant difference between length classes in the prevalence of the following lesions, angiomatosis (p=0.0062) in the lung, lymphoid depletion (0.043) in the spleen, glomerulonephritis (p=0.00009) in the kidney, and cardiomyocyte degeneration (p=0.022) and fibrosis (p=0.0021) in the heart, with a tendency towards more lesions in larger animals. The results of this investigation suggest that these lesions are more prevalent in larger, presumed to be older, stranded T. truncatus. The histopathologic results presented here provide important information on the diseases impacting T. truncatus around Florida, which can be used as a basis for future comparisons