ESR prepress abstract  -  doi: 10.3354/esr00772

Evaluation of morbillivirus exposure in cetaceans from the northern Gulf of Mexico 2010–2014

Deborah A. Fauquier*, Jenny Litz, Susan Sanchez, Kathleen Colegrove, Lori H. Schwacke, Leslie Hart, Jeremiah Saliki, Cynthia Smith, Tracey Goldstein, Sabrina Bowen-Stevens, Wayne McFee, Erin Fougeres, Blair Mase-Guthrie, Elizabeth Stratton, Ruth Ewing, Stephanie Venn-Watson, Ruth H. Carmichael, Connie Clemons-Chevis, Wendy Hatchett, Delphine Shannon, Steve Shippee, Suzanne Smith, Lydia Staggs, Mandy C. Tumlin, Noel L. Wingers, Teri K. Rowles

*Email: Deborah.Fauquier@noaa.gov

ABSTRACT: The potential role of morbillivirus was evaluated in the deaths of >1100 bottlenose dolphins Tursiops truncatus and other small cetaceans that stranded from February 2010 through July 2014, during the northern Gulf of Mexico (GOMx) unusual mortality event (UME). 142 live or fresh-dead cetaceans were selected for morbillivirus analysis, and results were combined with samples from 102 live, free-ranging bottlenose dolphins sampled during capture-release health assessments conducted from 2011-2014. Polymerase chain reaction (PCR) testing for morbillivirus was performed; 9.9% (14/142) of the stranded cetaceans and 1% (1/83) of the free-ranging live dolphins were positive for dolphin morbilliviral (DMV) RNA. In contrast, previous DMV dolphin die-offs had detectable DMV by PCR in 61% to 97% of animals tested. Histologic findings consistent with morbillivirus infection, including lymphoid depletion, bronchointerstitial pneumonia, syncytial cell formation, or meningoencephalitis, were found in 6.6% (9/136) of the cetaceans that had histologic examinations. Serological analysis using a virus neutralization assay detected 29% (5/17) of live stranded and 23% (23/102) of live free-ranging bottlenose dolphins had titers of 64 or greater for cetacean morbillivirus, indicating prior but not necessarily recent exposure to morbillivirus. Current findings suggest that DMV infection, although present in the northern GOMx, was sporadic and occurred at low levels and therefore was not the primary cause of the northern GOMx UME. Confirmation of DMV infections and existing DMV titers demonstrate continued exposure to morbillivirus among northern GOMx cetaceans since the first detection of this virus in the early 1990s.