title: Impact of route of exposure and challenge dose on the pathogenesis of H7N9 low pathogenicity avian influenza virus in chickens.
abstract: H7N9 influenza A first caused human infections in early 2013 in China. Virus genetics, histories of patient exposures to poultry, and previous experimental studies suggest the source of the virus is a domestic avian species, such as chickens. In order to better understand the ecology of this H7N9 in chickens, we evaluated the infectious dose and pathogenesis of A/Anhui/1/2013 H7N9 in two common breeds of chickens, White Leghorns (table-egg layers) and White Plymouth Rocks (meat chickens). No morbidity or mortality were observed with doses of 10(6) or 10(8)EID50/bird when administered by the upper-respiratory route, and the mean infectious dose (10(6) EID50) was higher than expected, suggesting that the virus is poorly adapted to chickens. Virus was shed at higher titers and spread to the kidneys in chickens inoculated by the intravenous route. Challenge experiments with three other human-origin H7N9 viruses showed a similar pattern of virus replication.
authors: Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, USA. Electronic address: Erica.spackman@ars.usda.gov.
authors: Erica
authors: E
authors: Spackman
authors: Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, USA. Electronic address: Mary.Pantin-jackwood@ars.usda.gov.
authors: Mary
authors: M
authors: Pantin-Jackwood
authors: Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, USA. Electronic address: David.Swayne@ars.usda.gov.
authors: David E
authors: DE
authors: Swayne
authors: Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, USA. Electronic address: David.Suarez@ars.usda.gov.
authors: David L
authors: DL
authors: Suarez
authors: Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, USA. Electronic address: Darrell.Kapczynski@ars.usda.gov.
authors: Darrell R
authors: DR
authors: Kapczynski
mesh_terms: D000818:Animals; D002645:Chickens; D002681:China; D064766:Influenza A Virus, H7N9 Subtype / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000473:pathology* / Q000821:virology*; D007668:Kidney / Q000821:virology; D017201:Virus Shedding
keywords: Avian influenza virus; Chicken disease; H7N9 influenza; Influenza pathogenesis