title: Saxitoxin increases phocine distemper virus replication upon in-vitro infection in harbor seal immune cells.
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.
authors.affiliation: 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.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Bogomolni
authors.affiliation: Department of Biology, University of New England, 11 Hills Beach Rd., Biddeford, ME 04005, USA.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Bass
authors.affiliation: Department of Biological Sciences, Florida Institute of Technology, 150 W University Blvd, Melbourne, FL 32901, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Fire
authors.affiliation: Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Rd., Storrs, CT 06269, USA.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Jasperse
authors.affiliation: Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Rd., Storrs, CT 06269, USA.
authors.forename: Milton
authors.initials: M
authors.lastname: Levin
authors.affiliation: Department of Fisheries and Oceans Canada, Central and Arctic Region, 501 University Crescent, Winnipeg, MB, Canada R3T 2N6.
authors.forename: Ole
authors.initials: O
authors.lastname: Nielsen
authors.affiliation: National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, USA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Waring
authors.affiliation: Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Rd., Storrs, CT 06269, USA.
authors.forename: Sylvain
authors.initials: S
authors.lastname: De Guise
keywords: Harbor seal; Lymphocyte proliferation; Morbillivirus; PDV USA 2006; Saxitoxin; Susceptibility