title: Emergence of canine distemper virus strains with modified molecular signature and enhanced neuronal tropism leading to high mortality in wild carnivores.
abstract: An ongoing canine distemper epidemic was first detected in Switzerland in the spring of 2009. Compared to previous local canine distemper outbreaks, it was characterized by unusually high morbidity and mortality, rapid spread over the country, and susceptibility of several wild carnivore species. Here, the authors describe the associated pathologic changes and phylogenetic and biological features of a multiple highly virulent canine distemper virus (CDV) strain detected in and/or isolated from red foxes (Vulpes vulpes), Eurasian badgers (Meles meles), stone (Martes foina) and pine (Martes martes) martens, from a Eurasian lynx (Lynx lynx), and a domestic dog. The main lesions included interstitial to bronchointerstitial pneumonia and meningopolioencephalitis, whereas demyelination--the classic presentation of CDV infection--was observed in few cases only. In the brain lesions, viral inclusions were mainly in the nuclei of the neurons. Some significant differences in brain and lung lesions were observed between foxes and mustelids. Swiss CDV isolates shared together with a Hungarian CDV strain detected in 2004. In vitro analysis of the hemagglutinin protein from one of the Swiss CDV strains revealed functional and structural differences from that of the reference strain A75/17, with the Swiss strain showing increased surface expression and binding efficiency to the signaling lymphocyte activation molecule (SLAM). These features might be part of a novel molecular signature, which might have contributed to an increase in virus pathogenicity, partially explaining the high morbidity and mortality, the rapid spread, and the large host spectrum observed in this outbreak.
authors.affiliation: Centre for Fish and Wildlife Health (FIWI), Institute of Animal Pathology, College of Veterinary Medicine, Vetsuisse Faculty, University of Bern, Laenggassstrasse 122, 3012, Bern, Switzerland. Francesco.origgi@vetsuisse.unibe.ch
authors.forename: F C
authors.initials: FC
authors.lastname: Origgi
authors.forename: P
authors.initials: P
authors.lastname: Plattet
authors.forename: U
authors.initials: U
authors.lastname: Sattler
authors.forename: N
authors.initials: N
authors.lastname: Robert
authors.forename: J
authors.initials: J
authors.lastname: Casaubon
authors.forename: F
authors.initials: F
authors.lastname: Mavrot
authors.forename: M
authors.initials: M
authors.lastname: Pewsner
authors.forename: N
authors.initials: N
authors.lastname: Wu
authors.forename: S
authors.initials: S
authors.lastname: Giovannini
authors.forename: A
authors.initials: A
authors.lastname: Oevermann
authors.forename: M H
authors.initials: MH
authors.lastname: Stoffel
authors.forename: V
authors.initials: V
authors.lastname: Gaschen
authors.forename: H
authors.initials: H
authors.lastname: Segner
authors.forename: M-P
authors.initials: MP
authors.lastname: Ryser-Degiorgis
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000829:Animals, Domestic; D000835:Animals, Wild; D001483:Base Sequence; D002335:Carnivora / Q000821:virology; D002460:Cell Line; D004196:Disease Outbreaks / Q000662:veterinary*; D004216:Distemper / Q000453:epidemiology / Q000473:pathology / Q000821:virology*; D004217:Distemper Virus, Canine / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D004285:Dogs; D006031:Glycosylation; D045586:Intranuclear Inclusion Bodies / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009474:Neurons / Q000502:physiology / Q000821:virology*; D010802:Phylogeny; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment / Q000662:veterinary; D017423:Sequence Analysis, RNA / Q000662:veterinary; D013557:Switzerland / Q000453:epidemiology; D056189:Viral Tropism; D014774:Virulence
chemical_list: D012367:RNA, Viral