title: Is dolphin morbillivirus virulent for white-beaked dolphins (Lagenorhynchus albirostris)?
abstract: The virulence of morbilliviruses for toothed whales (odontocetes) appears to differ according to host species. In 4 species of odontocetes, morbilliviruses are highly virulent, causing large-scale epizootics with high mortality. In 8 other species of odontocetes, including white-beaked dolphins (Lagenorhynchus albirostris), morbilliviruses have been found as an incidental infection. In these species, the virulence of morbilliviruses is not clear. Therefore, the admission of 2 white-beaked dolphins with morbillivirus infection into a rehabilitation center provided a unique opportunity to investigate the virulence of morbillivirus in this species. By phylogenetic analysis, the morbilliviruses in both animals were identified as a dolphin morbillivirus (DMV) most closely related to that detected in a white-beaked dolphin in Germany in 2007. Both animals were examined clinically and pathologically. Case No. 1 had a chronic neural DMV infection, characterized by polioencephalitis in the cerebrum and morbillivirus antigen expression limited to neurons and glial cells. Surprisingly, no nervous signs were observed in this animal during the 6 months before death. Case No. 2 had a subacute systemic DMV infection, characterized by interstitial pneumonia, leucopenia, lymphoid depletion, and DMV antigen expression in mononuclear cells and syncytia in the lung and in mononuclear cells in multiple lymphoid organs. Cause of death was not attributed to DMV infection in either animal. DMV was not detected in 2 contemporaneously stranded white-beaked dolphins. Stranding rate did not increase in the region. These results suggest that DMV is not highly virulent for white-beaked dolphins.
authors.affiliation: Dolfinarium Harderwijk, Strandboulevard Oost 1, Harderwijk, Netherlands niels.van.elk@dolfinarium.nl.
authors.forename: C E
authors.initials: CE
authors.lastname: van Elk
authors.affiliation: Erasmus Medical Center, Dr. Molewaterplein 50, Netherlands.
authors.forename: M W G
authors.initials: MW
authors.lastname: van de Bildt
authors.affiliation: Faculté de Médecine Vétérinaire, Boulevard de Colonster 20, Liège 1, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: Jauniaux
authors.affiliation: Faculteit Diergeneeskunde, Universiteit Utrecht, Yalelaan 1, De Uithof, Utrecht, Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Hiemstra
authors.affiliation: Erasmus Medical Center, Dr. Molewaterplein 50, Netherlands.
authors.forename: P R W A
authors.initials: PR
authors.lastname: van Run
authors.affiliation: SAC Veterinary Services, Inverness, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Foster
authors.affiliation: Stichting SOS-Dolfijn, Strandboulevard Oost 1, Harderwijk, Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Meerbeek
authors.affiliation: Erasmus Medical Center, Dr. Molewaterplein 50, Netherlands.
authors.forename: A D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.affiliation: Erasmus Medical Center, Dr. Molewaterplein 50, Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Kuiken
mesh_terms: D000818:Animals; D001483:Base Sequence; D004289:Dolphins / Q000821:virology*; D005260:Female; D005393:Fish Diseases / Q000473:pathology* / Q000821:virology; D005858:Germany; D008297:Male; D018103:Morbillivirus / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D018185:Morbillivirus Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D009426:Netherlands; D010802:Phylogeny; D017422:Sequence Analysis, DNA / Q000662:veterinary; D014774:Virulence
keywords: Lagenorhynchus albirostris; central nervous system; clinical signs; dolphin; immunohistochemistry; lungs; lymph nodes; morbillivirus