title: Reduced airborne transmission of oseltamivir-resistant pandemic A/H1N1 virus in ferrets.
abstract: BACKGROUND
  The H275Y neuraminidase mutation conferring oseltamivir resistance has been reported in several pandemic A/H1N1 (pH1N1) isolates. We sought to evaluate transmission of this mutant virus through the direct contact and the airborne (aerosol and droplet) routes in the ferret model.
  
  
  METHODS
  Groups of four ferrets were infected with either wild-type (WT) or oseltamivir-resistant pH1N1 (H275Y) strains. At 24 h following viral infection, a receptive ferret was introduced in the same cage as the infected animal to assess direct contact transmission. For the airborne transmission, naive ferrets were placed in a modified separate cage adjacent to that of their respective index ferret.
  
  
  RESULTS
  The H275Y mutant virus was as efficiently transmitted as the WT strain by direct contact, as 100% (4/4) of contact ferrets in both groups seroconverted and shed virus. Mean peak viral titres were similar in both groups (4 × 10(4) and 2.63 × 10(4) plaque-forming units/ml after WT or H275Y mutant virus transmission, respectively). Peak viral shedding occurred on day 2 post-contact for the WT group and on day 4 post-contact for the H275Y mutant group. By contrast, airborne transmission of the mutant strain was less efficient, as only 25% (1/4) of contact ferrets seroconverted and shed virus, whereas 100% (4/4) of the WT ferrets did. Peak of viral replication was delayed compared to direct contact transmission and occurred on day 4 post-contact.
  
  
  CONCLUSIONS
  Transmission of the H275Y pH1N1 mutant strain by the airborne route is somewhat compromised, which may limit its widespread dissemination.
authors.affiliation: CHUQ-CHUL Research Center in Infectious Diseases and Laval University, Québec City, QC, Canada.
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Hamelin
authors.forename: Mariana
authors.initials: M
authors.lastname: Baz
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouhy
authors.forename: Edith
authors.initials: E
authors.lastname: Beaulieu
authors.forename: Karen
authors.initials: K
authors.lastname: Dubé
authors.forename: Corey
authors.initials: C
authors.lastname: Mallett
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000391:Air Microbiology; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D018562:Disease Transmission, Infectious / Q000517:prevention & control; D024882:Drug Resistance, Viral / Q000235:genetics*; D005289:Ferrets; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008297:Male; D009439:Neuraminidase / Q000235:genetics; D009976:Orthomyxoviridae Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics / Q000635:transmission*; D053139:Oseltamivir / Q000494:pharmacology / Q000627:therapeutic use*; D058873:Pandemics; D013997:Time Factors; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects* / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir; D009439:Neuraminidase