Grading of cardiac histologic lesions from dolphins stranding following the Deepwater Horizon oil spill compared to reference dolphins

Grading of histologic heart lesions was performed on 100 common bottlenose dolphins (Tursiops truncatus) that stranded in the northern Gulf of Mexico from 2010 - February 2019, following the Deepwater Horizon (DWH) oil spill. Heart lesions were graded in 42 reference dolphins stranding outside of the oil spill time frame and location for reference. Lesions able to be consistently scored across stranded dolphins included myocyte nuclear rowing, myocyte nuclear karyomegaly, myocardial fibrosis, myocardial fibrosis severity, myocarditis, myocardial degeneration and/or necrosis, vascular arteriosclerosis, myocardial lipofuscinosis, and the presence of heart failure.