title: Transmission of swine influenza virus to humans after exposure to experimentally infected pigs.
abstract: Two people developed symptoms of influenza 36 h after collecting nasal swabs from pigs experimentally infected with A/Sw/IN/1726/88 (Sw/IN). Pharyngeal swabs from these persons tested positive for influenza virus RNA 8 days after infection. Analysis of hemi-nested polymerase chain reaction (PCR) products indicated that the hemagglutinin (HA) segments of the isolates were genetically related to the HA of Sw/IN. Four influenza A virus isolates (A/WI/4754/94, A/WI/4756/94, A/WI/4758/94, A/WI/4760/94) were recovered from a 39-year-old man and 2 (A/WI/4755/94, A/WI/4757/94) from a 31-year-old woman. The HAs of the isolates were antigenically indistinguishable from the virus used to infect the pigs. Sequence analysis of the HA genes indicated they were 99.7% identical to the HA of the virus used in the experiment. Multisegment reverse transcription-PCR proved that all of the segments originated from Sw/IN, demonstrating that transmission of swine H1N1 viruses to humans occurs directly and readily, despite Animal Biosafety Level 3 containment practices used for these experiments.
authors.affiliation: Department of Pathobiological Sciences, University of Wisconsin-Madison, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Wentworth
authors.forename: M W
authors.initials: MW
authors.lastname: McGregor
authors.forename: M D
authors.initials: MD
authors.lastname: Macklin
authors.forename: V
authors.initials: V
authors.lastname: Neumann
authors.forename: V S
authors.initials: VS
authors.lastname: Hinshaw
mesh_terms: D000328:Adult; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D016679:Genome, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D007251:Influenza, Human / Q000635:transmission* / Q000662:veterinary / Q000821:virology*; D008297:Male; D008969:Molecular Sequence Data; D010614:Pharynx / Q000821:virology; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D015047:Zoonoses
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus