Weathered MC252 crude oil-induced anemia and abnormal erythroid morphology in double-crested cormorants (Phalacrocorax auritus) with light microscopic and ultrastructural description of Heinz bodies

Authors

K. E. Harr, URIKA, LLC.Follow
Fred L. Cunningham, Mississippi State UniversityFollow
Chris A. Pritsos, University of NevadaFollow
Karen L. Pritsos, University of Nevada
Thivanka Muthumalage, University of Nevada
Brian S. Dorr, Mississippi State UniversityFollow
Katherine E. Horak, USDA/APHIS/WS National Wildlife Research CenterFollow
Katie C. Hanson-Dorr, USDA National Wildlife Research CenterFollow
Karen M. Dean, Abt AssociatesFollow
Dave Cacela, Abt AssociatesFollow
Andrew K. McFadden, Abt Associates
Jane E. Link, Michigan State UniversityFollow
Katherine A. Healy, US Fish and Wildlife ServiceFollow
Pete Tuttle, US Fish and Wildlife Service
Steven J. Bursian, Michigan State UniversityFollow

Document Type

Article

Date of this Version

2017

Citation

Harr, K.E., Ecotoxicology and Environmental Safety (2017), http://dx.doi.org/10.1016/j.ecoenv.2017.07.030

Comments

U.S. government work.

Abstract

Injury assessment of birds following the Deepwater Horizon (DWH) oil spill in 2010 was part of the Natural Resource Damage Assessment. One reported effect was hemolytic anemia with the presence of Heinz bodies (HB) in birds, however, the role of route and magnitude of exposure to oil is unknown. The purpose of the present study was to determine if double-crested cormorants (Phalacocorax auritis; DCCO) exposed orally and dermally to artificially weathered crude oil would develop hemolytic anemia including HB and reticulocytosis. In the oral experiment, sub-adult, mixed-sex DCCOs were fed control (n = 8) or oil–injected fish with a daily target dose of 5 (n = 9) or 10 (n = 9) ml oil/kg for 21 days. Then, subadult control (n = 12) and treated (n = 13) cormorant groups of similar sex-ratio were dermally treated with approximately 13 ml of water or weathered MC252 crude oil, respectively, every 3 days for 6 dosages approximating 20% surface coverage. Collected whole blood samples were analyzed by light (new methylene blue) and transmission electron microscopy. Both oral and dermal treatment with weathered DWH MC252 crude oil induced regenerative, but inadequately compensated, anemia due to hemolysis and hematochezia as indicated by decreased packed cell volume, relative increase in reticulocytes with lack of difference in corrected reticulocyte count, and morphologic evidence of oxidant damage at the ultrastructural level. Hemoglobin precipitation, HB formation, degenerate organelles, and systemic oxidant damage were documented. Heinz bodies were typically <2 >μm in length and smaller than in mammals. These oblong cytoplasmic inclusions were difficult to see upon routine blood smear evaluation and lacked the classic button appearance found in mammalian red blood cells. They could be found as light, homogeneous blue inclusions upon new methylene blue staining. Ultrastructurally, HB appeared as homogeneous, electron-dense structures within the cytosol and lacked membranous structure. Oxidant damage in avian red blood cells results in degenerate organelles and precipitated hemoglobin or HB with different morphology than that found in mammalian red blood cells. Ultrastructural evaluation is needed to definitively identify HB and damaged organelles to confirm oxidant damage. The best field technique based on the data in this study is assessment of PCV with storage of blood in glutaraldehyde for possible TEM analysis.