Volume 11 Issue 6
Cetacean Morbillivirus: Current Knowledge and Future Directions
Marie-Françoise Van Bressem,Pádraig J. Duignan,Ashley Banyard,Michelle Barbieri,Kathleen M Colegrove,Sylvain De Guise,Giovanni Di Guardo,Andrew Dobson,Mariano Domingo,Deborah Fauquier,Antonio Fernandez,Tracey Goldstein,Bryan Grenfell,Kátia R. Groch,Frances Gulland,Brenda A Jensen,Paul D Jepson,Ailsa Hall,Thijs Kuiken,Sandro Mazzariol,
1Cetacean Conservation Medicine Group (CMED), Peruvian Centre for Cetacean Research (CEPEC), Pucusana, Lima 20, Peru
2Department of Ecosystem and Public Health, University of Calgary, Calgary, AL T2N 4Z6, Canada
3Wildlife Zoonoses and Vector Borne Disease Research Group, Animal and Plant Health Agency (APHA), Weybridge, Surrey KT15 3NB, UK
4The Marine Mammal Centre, Sausalito, CA 94965, USA
5Zoological Pathology Program, College of Veterinary Medicine, University of Illinois at Maywood, IL 60153 , USA
6Department of Pathobiology and Veterinary Science, and Connecticut Sea Grant College Program, University of Connecticut, Storrs, CT 06269, USA
7Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy
8Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
9Centre de Recerca en Sanitat Animal (CReSA), Autonomous University of Barcelona, Bellaterra, Barcelona 08193, Spain
10National Marine Fisheries Service, Marine Mammal Health and Stranding Response Program, Silver Spring, MD 20910, USA
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Abstract
We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported.
Keywords: cetacean morbillivirus; epidemics; mass stranding; SLAM; phylogeny; pathogenesis; diagnosis; endemic infections