title: Phenotypes influencing the transmissibility of highly pathogenic avian influenza viruses in chickens.
abstract: To identify critical phenotypes that affect avian influenza virus transmission in chickens, we compared the transmissibility of three H5N1 highly pathogenic viruses of different pathogenicity in chickens by monitoring the exact time of death using wireless thermo-sensors. This study showed that, despite quick deaths, the most virulent H5N1 A/chicken/Yamaguchi/7/2004 transmitted quickly in chickens via contact and airborne routes. Intermediate virulent H5N1 A/chicken/Miyazaki/K11/2007 spread moderately and less virulent H5N1 A/duck/Yokohama/aq10/2003, causing severe clinical signs and a long period to death, spread slowly among the animals. The transmissibility was correlated with virus titres of oropharyngeal and cloacal swabs, and the time for swab virus titres to reach 50 % chicken infective dose affected the transmission speed. These results demonstrate that peak virus titres excreted and the time required for virus titres to reach a minimal chicken infectious dose may be the critical phenotypes influencing the transmissibility of highly pathogenicity avian influenza viruses in chickens.
authors.affiliation: National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
authors.forename: Koutaro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hironao
authors.initials: H
authors.lastname: Okada
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Itoh
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Tada
authors.forename: Kenji
authors.initials: K
authors.lastname: Tsukamoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000635:transmission* / Q000821:virology*; D010641:Phenotype; D013045:Species Specificity; D013997:Time Factors; D014774:Virulence; D017201:Virus Shedding
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus