Modelling cetacean morbillivirus outbreaks in an endangered killer whale population

Weiss, Michael N.; Franks, Daniel W.; Balcomb, Kenneth C.; Ellifrit, David K.; Silk, Matthew J.; Cant, Michael A.; Croft, Darren P.

doi:10.1016/j.biocon.2019.108398

Cited by 16 publications

(12 citation statements)

References 65 publications

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“…Despite testing of postmortem serum, screening tissues by molecular studies and looking for cytoplasmic inclusions and syncytia microscopically, morbilliviruses, such as cetacean morbillivirus and morbillivirus antibodies have not been detected. This further supports the potential that exposure to these viruses could increase extinction risk in immunologically naïve and endangered killer whale populations like the southern residents [10,52].…”

Section: Infectious Diseasesupporting

confidence: 65%

Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013

et al. 2020

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Understanding health and mortality in killer whales (Orcinus orca) is crucial for management and conservation actions. We reviewed pathology reports from 53 animals that stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013 and used data from 35 animals that stranded from 2001 to 2017 to assess association with morphometrics, blubber thickness, body condition and cause of death. Of the 53 cases, cause of death was determined for 22 (42%) and nine additional animals demonstrated findings of significant importance for population health. Causes of calf mortalities included infectious disease, nutritional, and congenital malformations. Mortalities in sub-adults were due to trauma, malnutrition, and infectious disease and in adults due to bacterial infections, emaciation and blunt force trauma. Death related to human interaction was found in every age class. Important incidental findings included concurrent sarcocystosis and toxoplasmosis, uterine leiomyoma, vertebral periosteal proliferations, cookiecutter shark (Isistius sp.) bite wounds, excessive tooth wear and an ingested fish hook. Blubber thickness increased significantly with body length (all p < 0.001). In contrast, there was no relationship between body length and an index of body condition (BCI). BCI was higher in animals that died from trauma. This study establishes a baseline for understanding health, nutritional status and causes of mortality in stranded killer whales. Given the evidence of direct human interactions on all age classes, in order to be most successful recovery efforts should address the threat of human interactions, especially for small endangered groups of killer whales that occur in close proximity to large human populations, interact with recreational and commercial fishers and transit established shipping lanes.

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Section: Infectious Diseasesupporting

confidence: 65%

Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013

et al. 2020

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“…This is especially concerning as many of Hawaii’s cetacean stocks are small, island-associated, resident populations that may be particularly vulnerable to any reduction in population size because of an already low number of breeding individuals such as the endangered main Hawaiian Islands insular false killer whale (Pseudorca crassidens) , estimated at only 167 individuals 38 . Novel disease is considered a major hurdle to endangered population recovery and even poses the threat of extinction as demonstrated in a recent effort to model the impact of a morbillivirus outbreak on endangered Southern resident killer whales ( Orcinus orca ) from the Pacific Northwest 39 . Southern resident killer whales were determined to be highly vulnerable to a disease outbreak 39 ; similarly, a novel disease outbreak among Hawaii’s endangered false killer whale population could have a disastrous impact.…”

Section: Discussionmentioning

confidence: 99%

“…Novel disease is considered a major hurdle to endangered population recovery and even poses the threat of extinction as demonstrated in a recent effort to model the impact of a morbillivirus outbreak on endangered Southern resident killer whales ( Orcinus orca ) from the Pacific Northwest 39 . Southern resident killer whales were determined to be highly vulnerable to a disease outbreak 39 ; similarly, a novel disease outbreak among Hawaii’s endangered false killer whale population could have a disastrous impact. Melon-headed whales ( Peponocephala electra ) in Hawaii are also genetically and behaviorally distinct, with a Kohala resident population of approximately 500 individuals inhabiting shallower waters off the Big Island 40 .…”

Section: Discussionmentioning

confidence: 99%

Novel cetacean morbillivirus in a rare Fraser’s dolphin (Lagenodelphis hosei) stranding from Maui, Hawai‘i

West

Silva‐Krott

Landrau‐Giovannetti

et al. 2021

Sci Rep

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Cetacean morbillivirus (CeMV) is a global threat to cetaceans. We report a novel morbillivirus from a Fraser’s dolphin (Lagenodelphis hosei) that stranded in Maui, Hawaii in 2018 that is dissimilar to the beaked whale morbillivirus previously identified from Hawaii and to other CeMV strains. Histopathological findings included intranuclear inclusions in bile duct epithelium, lymphoid depletion, rare syncytial cells and non-suppurative meningitis. Cerebellum and lung tissue homogenates were inoculated onto Vero.DogSLAMtag cells for virus isolation and cytopathic effects were observed, resulting in the formation of multinucleated giant cells (i.e., syncytia). Transmission electron microscopy of infected cell cultures also revealed syncytial cells with intracytoplasmic and intranuclear inclusions of viral nucleocapsids, consistent with the ultrastructure of a morbillivirus. Samples of the cerebellum, lung, liver, spleen and lymph nodes were positive for morbillivirus using a reverse transcription-polymerase chain reaction. The resulting 559 bp L gene sequence had the highest nucleotide identity (77.3%) to porpoise morbillivirus from Northern Ireland and the Netherlands. The resulting 248 bp P gene had the highest nucleotide identity to porpoise morbillivirus in Northern Ireland and the Netherlands and to a stranded Guiana dolphin (Sotalia guianensis) in Brazil (66.9%). As Fraser’s dolphins are a pelagic species that infrequently strand, a novel strain of CeMV may be circulating in the central Pacific that could have additional population impacts through transmission to other small island-associated cetacean species.

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“…In addition, social networks could help managers understand disease risk and target vaccinations. While our systematic review found only three studies explicitly linking social networks and disease, more recent work has expanded the application of social networks to disease management, by estimating age and sex specific risk (Leu et al, 2020), explicitly modelling the spread of specific pathogens along with possible vaccination strategies (Weiss et al, 2020), and using randomisation procedures to determine the relevance of association networks to observed disease outbreaks (Powell et al, 2020). Further work determining the impact of social network structure on population-level disease risk in a comparative context could further inform conservation efforts.…”

Section: Future Research Directionsmentioning

confidence: 99%

Diversity and Consequences of Social Network Structure in Toothed Whales

2021

Self Cite

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Toothed whales (suborder Odontoceti) are highly social, large brained mammals with diverse social systems. In recent decades, a large body of work has begun investigating these dynamic, complex societies using a common set of analytical tools: social network analysis. The application of social network theory to toothed whales enables insight into the factors that underlie variation in social structure in this taxon, and the consequences of these structures for survival, reproduction, disease transmission, and culture. Here, we perform a systematic review of the literature regarding toothed whale social networks to identify broad patterns of social network structure across species, common drivers of individual social position, and the consequences of network structure for individuals and populations. We also identify key knowledge gaps and areas ripe for future research. We recommend that future studies attempt to expand the taxonomic breadth and focus on standardizing methods and reporting as much as possible to allow for comparative analyses to test evolutionary hypotheses. Furthermore, social networks analysis may provide key insights into population dynamics as indicators of population health, predictors of disease risk, and as direct drivers of survival and reproduction.

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Modelling cetacean morbillivirus outbreaks in an endangered killer whale population

Cited by 16 publications

References 65 publications

Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013

Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013

Novel cetacean morbillivirus in a rare Fraser’s dolphin (Lagenodelphis hosei) stranding from Maui, Hawai‘i

Diversity and Consequences of Social Network Structure in Toothed Whales

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