title: Morbillivirus-associated unusual mortality event in South Australian bottlenose dolphins is largest reported for the Southern Hemisphere.
abstract: Cases of morbillivirus have been recorded in the Southern Hemisphere but have not been linked to significant marine mammal mortality. Post-mortems were conducted on 58 carcasses (44 Indo-Pacific bottlenose dolphins, two common bottlenose dolphins, 12 short-beaked common dolphins) from South Australia during 2005-2013, including an unusual mortality event (UME) in St Vincent Gulf Bioregion (SVG) during 2013. Diagnostic pathology, circumstance of death, body condition, age and stomach contents were documented for Indo-Pacific bottlenose dolphins. At least 50 dolphins died during the UME, 41 were Indo-Pacific bottlenose dolphins and most were young. The UME lasted about seven months and had two peaks, the first being the largest. Effect on the population is unknown. Diagnostic testing for morbillivirus was conducted on 57 carcasses, with evidence for infection in all species during 2011-2013. All tested UME bottlenose dolphins were positive for cetacean morbillivirus (CeMV), and the pathology included interstitial pneumonia, lymphoid depletion and syncytia. Concurrent pathologies, including lung parasite and fungal infections, and severe cutaneous bruising were observed in many dolphins. The event coincided with elevated water temperatures, a diatom bloom and significant fish die-offs. We conclude that the cause for the UME was multifactorial and that CeMV was a major contributor.
authors.affiliation: South Australian Museum , North Terrace, Adelaide, South Australia 5000 , Australia.
authors.forename: C M
authors.identifier: 0000-0002-4452-8259
authors.initials: CM
authors.lastname: Kemper
authors.affiliation: South Australian Museum , North Terrace, Adelaide, South Australia 5000 , Australia.
authors.forename: I
authors.initials: I
authors.lastname: Tomo
authors.affiliation: Australian Animal Health Laboratory , Commonwealth Scientific and Industrial Research Organisation , Private Bag 24, 5 Portarlington Road, Geelong, Victoria 3220 , Australia.
authors.forename: J
authors.initials: J
authors.lastname: Bingham
authors.affiliation: Gribbles Veterinary Laboratory , 33 Flemington Street, Glenside, South Australia 5065 , Australia.
authors.forename: S S
authors.initials: SS
authors.lastname: Bastianello
authors.affiliation: Australian Animal Health Laboratory , Commonwealth Scientific and Industrial Research Organisation , Private Bag 24, 5 Portarlington Road, Geelong, Victoria 3220 , Australia.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Lot 30A, Seaview Road, Yatala Vale, South Australia 5126 , Australia.
authors.forename: S E
authors.initials: SE
authors.lastname: Gibbs
authors.affiliation: Animal and Veterinary Sciences , University of Adelaide , Roseworthy, South Australia 5371 , Australia.
authors.forename: L
authors.initials: L
authors.lastname: Woolford
authors.affiliation: Biosecurity SA, Primary Industries and Regions South Australia , Research Centre , Lenswood, South Australia 5240 , Australia.
authors.forename: C
authors.initials: C
authors.lastname: Dickason
authors.affiliation: Department of Environment , Water and Natural Resources , GPO Box 1047, Adelaide, South Australia 5001 , Australia.
authors.forename: D
authors.initials: D
authors.lastname: Kelly
keywords: Australia; Indo-Pacific bottlenose dolphin; cetacean morbillivirus; environmental perturbation; unusual mortality event