Saxitoxin increases phocine distemper virus replication upon in-vitro infection in harbor seal immune cells

Andrea L Bogomolni; Anna L Bass; Spencer Fire; Lindsay Jasperse; Milton Levin; Ole Nielsen; Gordon Waring; Sylvain De Guise

doi:10.1016/j.hal.2015.10.013

Saxitoxin increases phocine distemper virus replication upon in-vitro infection in harbor seal immune cells

Harmful Algae. 2016 Jan:51:89-96. doi: 10.1016/j.hal.2015.10.013. Epub 2015 Dec 14.

Authors

Andrea L Bogomolni¹, Anna L Bass², Spencer Fire³, Lindsay Jasperse⁴, Milton Levin⁴, Ole Nielsen⁵, Gordon Waring⁶, Sylvain De Guise⁴

Affiliations

¹ Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Rd., Storrs, CT 06269, USA; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. Electronic address: abogomolni@gmail.com.
² Department of Biology, University of New England, 11 Hills Beach Rd., Biddeford, ME 04005, USA.
³ Department of Biological Sciences, Florida Institute of Technology, 150 W University Blvd, Melbourne, FL 32901, USA.
⁴ Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Rd., Storrs, CT 06269, USA.
⁵ Department of Fisheries and Oceans Canada, Central and Arctic Region, 501 University Crescent, Winnipeg, MB, Canada R3T 2N6.
⁶ National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, USA.

PMID: 28003064
DOI: 10.1016/j.hal.2015.10.013

Abstract

Several marine mammal epizootics have been closely linked to infectious diseases, as well as to the biotoxins produced by harmful algal blooms (HABs). In two of three saxitoxin (STX) associated mortality events, dolphin morbillivirus (DMV) or phocine distemper virus (PDV) was isolated in affected individuals. While STX is notorious for its neurotoxicity, immunotoxic effects have also been described. This study investigated the role of STX in altering immune function, specifically T lymphocyte proliferation, in harbor seals (Phoca vitulina concolor) upon in-vitro exposure. In addition, the study also examined whether exposure to STX could alter the susceptibility of harbor seal immune cells to PDV infection upon in-vitro exposure. STX caused an increase in harbor seal lymphocyte proliferation at 10ppb and exposure to STX significantly increased the amount of virus present in lymphocytes. These results suggest that low levels of STX within the range of those reported in northeast U.S. seals may affect the likelihood of systemic PDV infection upon in-vivo exposure in susceptible seals. Given the concurrent increase in morbillivirus epizootics and HAB events in the last 25 years, the relationship between low level toxin exposure and host susceptibility to morbillivirus needs to be further explored.

Keywords: Harbor seal; Lymphocyte proliferation; Morbillivirus; PDV USA 2006; Saxitoxin; Susceptibility.