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

Abstract

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.

Molecular Diagnosis of Cetacean Morbillivirus in Beaked Whales Stranded in the Canary Islands (1999–2017)

“…Sci. 2022, 9, 121 2 of 18 fied from Hawaii and to other CeMV strains, showing an 83.9-88.7% nucleotide similarity depending on the P or N gens of these reported sequences [12].…”

“…Two lineages of CeMV have been proposed [ 1 , 6 ]: CeMV-1 for the “old” northern hemisphere lineage that includes dolphin morbillivirus (DMV) [ 7 ], porpoise morbillivirus (PMV) [ 7 ], pilot-whale morbillivirus (PWMV) [ 8 ] and beaked-whale morbillivirus (BWMV) [ 9 ] strains; and CeMV-2 for the “new” southern hemisphere lineage, consisting of virus strains detected in a Guiana dolphin ( Sotalia guianensis ) from Brazil [ 10 ] and in Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) from Western Australia [ 11 ]. In addition, it has been recently reported that a novel morbillivirus was detected in a Fraser’s dolphin ( Lagenodelphis hosei ) stranded in Hawaii that is dissimilar to the BWMV previously identified from Hawaii and to other CeMV strains, showing an 83.9–88.7% nucleotide similarity depending on the P or N gens of these reported sequences [ 12 ].…”

Neuropathological Characterization of Dolphin Morbillivirus Infection in Cetaceans Stranded in Italy

“…A member of the genus Morbillivirus (family Paramyxoviridae, subfamily Orthoparamyxovirinae), CeMV is the natural agent with the greatest impact on cetacean health and conservation worldwide [ 4 ]. This non-segmented single-stranded RNA virus includes three well-characterized strains: dolphin morbillivirus (DMV), porpoise morbillivirus, and pilot whale morbillivirus, plus four more strains recently identified in Hawaii and the southern hemisphere [ 5 , 6 , 7 , 8 ].…”

Prevalence and genotype of Toxoplasma gondii in stranded Hawaiian cetaceans

“…RNA was extracted from the tissues using the RNeasy Plus Mini Kit (Qiagen) using the manufacturer's instructions. RT-PCR for each tissue extract was run using the OneSTEP RT-PCR Kit (Qiagen), with the primers and thermocycler settings described by West et al (2021).…”