title: Pathogenesis of Influenza A/H5N1 virus infection in ferrets differs between intranasal and intratracheal routes of inoculation.
abstract: Most patients infected with highly pathogenic avian influenza A/H5N1 virus develop severe pneumonia resulting in acute respiratory distress syndrome, with extrarespiratory disease as an uncommon complication. Intranasal inoculation of ferrets with influenza A/H5N1 virus causes lesions in both the respiratory tract and extrarespiratory organs (primarily brain). However, the route of spread to extrarespiratory organs and the relative contribution of extrarespiratory disease to pathogenicity are largely unknown. In the present study, we characterized lesions in the respiratory tract and central nervous system (CNS) of ferrets (n = 8) inoculated intranasally with influenza virus A/Indonesia/5/2005 (H5N1). By 7 days after inoculation, only 3 of 8 ferrets had a mild or moderate bronchointerstitial pneumonia. In contrast, all 8 ferrets had moderate or severe CNS lesions, characterized by meningoencephalitis, choroiditis, and ependymitis, and centered on tissues adjoining the cerebrospinal fluid. These findings indicate that influenza A/H5N1 virus spread directly from nasal cavity to brain, and that CNS lesions contributed more than pulmonary lesions to the pathogenicity of influenza A/H5N1 virus infection in ferrets. In comparison, intratracheal inoculation of ferrets with the same virus reproducibly caused severe bronchointerstitial pneumonia. The method of virus inoculation requires careful consideration in the design of ferret experiments as a model for influenza A/H5N1 in humans.
authors.affiliation: Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Rogier
authors.initials: R
authors.lastname: Bodewes
authors.forename: Joost H C M
authors.initials: JH
authors.lastname: Kreijtz
authors.forename: Geert
authors.initials: G
authors.lastname: van Amerongen
authors.forename: Ron A M
authors.initials: RA
authors.lastname: Fouchier
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.forename: Guus F
authors.initials: GF
authors.lastname: Rimmelzwaan
authors.forename: Thijs
authors.initials: T
authors.lastname: Kuiken
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D001921:Brain / Q000821:virology; D001927:Brain Diseases / Q000209:etiology / Q000473:pathology*; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D005289:Ferrets; D007124:Immunoenzyme Techniques; D053124:Influenza A Virus, H5N1 Subtype / Q000472:pathogenicity*; D007442:Intubation, Intratracheal; D007668:Kidney / Q000166:cytology / Q000821:virology; D008171:Lung Diseases / Q000209:etiology / Q000473:pathology*; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000821:virology*; D014779:Virus Replication