title: Genetic and pathobiologic characterization of pandemic H1N1 2009 influenza viruses from a naturally infected swine herd.
abstract: Since its initial identification in Mexico and the United States, concerns have been raised that the novel H1N1 influenza virus might cause a pandemic of severity comparable to that of the 1918 pandemic. In late April 2009, viruses phylogenetically related to pandemic H1N1 influenza virus were isolated from an outbreak on a Canadian pig farm. This outbreak also had epidemiological links to a suspected human case. Experimental infections carried out in pigs using one of the swine isolates from this outbreak and the human isolate A/Mexico/InDRE4487/2009 showed differences in virus recovery from the lower respiratory tract. Virus was consistently isolated from the lungs of pigs infected with A/Mexico/InDRE4487/2009, while only one pig infected with A/swine/Alberta/OTH-33-8/2008 yielded live virus from the lung, despite comparable amounts of viral RNA and antigen in both groups of pigs. Clinical disease resembled other influenza virus infections in swine, albeit with somewhat prolonged virus antigen detection and delayed viral-RNA clearance from the lungs. There was also a noteworthy amount of genotypic variability among the viruses isolated from the pigs on the farm. This, along with the somewhat irregular pathobiological characteristics observed in experimentally infected animals, suggests that although the virus may be of swine origin, significant viral evolution may still be ongoing.
authors.affiliation: Canadian Food Inspection Agency (CFIA), National Centre for Foreign Animal Disease (NCFAD), Manitoba, Canada. hana.weingartl@inspection.gc.ca
authors.forename: Hana M
authors.initials: HM
authors.lastname: Weingartl
authors.forename: Yohannes
authors.initials: Y
authors.lastname: Berhane
authors.forename: Tamiko
authors.initials: T
authors.lastname: Hisanaga
authors.forename: James
authors.initials: J
authors.lastname: Neufeld
authors.forename: Helen
authors.initials: H
authors.lastname: Kehler
authors.forename: Carissa
authors.initials: C
authors.lastname: Emburry-Hyatt
authors.forename: Kathleen
authors.initials: K
authors.lastname: Hooper-McGreevy
authors.forename: Samantha
authors.initials: S
authors.lastname: Kasloff
authors.forename: Brett
authors.initials: B
authors.lastname: Dalman
authors.forename: Jan
authors.initials: J
authors.lastname: Bystrom
authors.forename: Soren
authors.initials: S
authors.lastname: Alexandersen
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: John
authors.initials: J
authors.lastname: Pasick
mesh_terms: D000818:Animals; D002170:Canada / Q000453:epidemiology; D004196:Disease Outbreaks; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000821:virology; D008168:Lung / Q000166:cytology / Q000473:pathology / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000276:immunology / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000302:isolation & purification; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000276:immunology / Q000821:virology; D015047:Zoonoses / Q000453:epidemiology / Q000821:virology
chemical_list: D012367:RNA, Viral