Did algal toxin and Klebsiella infections cause the unexplained 2007 mass mortality event in Danish and Swedish marine mammals?

Autor: Mollerup IM; Natural History Museum of Denmark, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark; Section for Molecular Ecology and Evolution, Globe Institute, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark., Bjørneset J; Natural History Museum of Denmark, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark; Section for Molecular Ecology and Evolution, Globe Institute, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark., Krock B; Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany., Jensen TH; Aalborg Zoo/Section of Biology and Environmental Science, University of Aalborg, Fredrik Bajers Vej 7, H, 9220 Aalborg, Denmark., Galatius A; Section for Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark., Dietz R; Section for Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark., Teilmann J; Section for Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark., van den Brand JMA; Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands., Osterhaus A; Research Center Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine, Bünteweg 17, 30559 Hannover, Germany., Kokotovic B; Reference Laboratory for Antimicrobial Resistance, Department of Bacteria, Parasites & Fungi, Statens Seruminstitut, Artillerivej 5, 2300 Copenhagen S, Denmark., Lundholm N; Natural History Museum of Denmark, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark. Electronic address: nlundholm@snm.ku.dk., Olsen MT; Section for Molecular Ecology and Evolution, Globe Institute, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen K, Denmark; Section for Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark. Electronic address: morten.olsen@sund.ku.dk.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Mar 01; Vol. 914, pp. 169817. Date of Electronic Publication: 2024 Jan 05.
DOI: 10.1016/j.scitotenv.2023.169817
Abstrakt: An unusual mass mortality event (MME) of harbour seals (Phoca vitulina) and harbour porpoises (Phocoena phocoena) occurred in Denmark and Sweden in June 2007. Prior to this incident, the region had experienced two MMEs in harbour seals caused by Phocine Distemper Virus (PDV) in 1988 and 2002. Although epidemiology and symptoms of the 2007 MME resembled PDV, none of the animals examined for PDV tested positive. Thus, it has been speculated that another - yet unknown - pathogen caused the June 2007 MME. To shed new light on the likely cause of death, we combine previously unpublished veterinary examinations of harbour seals with novel analyses of algal toxins and algal monitoring data. All harbour seals subject to pathological examination showed pneumonia, but were negative for PDV, influenza and coronavirus. Histological analyses revealed septicaemia in multiple animals, and six animals tested positive for Klebsiella pneumonia. Furthermore, we detected the algal Dinophysis toxin DTX-1b (1-115 ng g -1 ) in five seals subject to toxicology, representing the first time DTX-1b has been detected in marine vertebrates. However, no animals tested positive for both Klebsiella and toxins. Thus, while our relatively small sample size prevent firm conclusions on causative agents, we speculate that the unexplained MME may have been caused by a chance incidence of multiple pathogens acting in parallel in June 2007, including Dinophysis toxin and Klebsiella. Our study illustrates the complexity of wildlife MMEs and highlights the need for thorough sampling during and after MMEs, as well as additional research on and monitoring of DTX-1b and other algal toxins in the region.
Competing Interests: Declaration of competing interest The authors declare that they know of no competing financial- or personal relationships that could influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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