title: Quantification of dust-borne transmission of highly pathogenic avian influenza virus between chickens.
abstract: BACKGROUND
  Understanding the transmission of highly pathogenic avian influenza virus (HPAIv) between poultry flocks is essential to prevent and control epidemics. Dust, produced in infected chicken flocks, has been hypothesized to be an important mechanical vector for between-flock transmission of HPAIv.
  
  
  OBJECTIVE
  The aim of our study was to quantify the amount of virus shed by infected birds and its relation to deposition of virus in the environment and the rate of dust-borne transmission between groups of chickens.
  
  
  METHODS
  Four replicate experiments were performed, each replicate with two groups of 14 chickens housed in two separate rooms. In one group, chickens were inoculated with HPAIv. Ventilation forced the air from that room to the second (recipient) group through a tube. Deceased birds in the inoculated group were replaced with new susceptible birds up to day 10 p.i. Dust samples were collected daily. Trachea and cloaca swabs were collected daily to determine virus shedding and virus spread to the recipient group.
  
  
  RESULTS
  The amount of virus detected in dust samples in the recipient room was, on average, 10(3·7) EID(50) /m(3) . Virus transmission from the inoculated to the recipient group occurred in two experiments. The transmission rate parameter for dust-borne transmission was estimated at 0·08 new infections/infectious chicken/day.
  
  
  CONCLUSIONS
  The results of this study are a first step to elucidate the importance of dust-borne transmission of HPAIv between flocks and help interpret environmental samples.
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. d.spekreijse@uu.nl
authors.forename: Dieuwertje
authors.initials: D
authors.lastname: Spekreijse
authors.forename: Annemarie
authors.initials: A
authors.lastname: Bouma
authors.forename: Guus
authors.initials: G
authors.lastname: Koch
authors.forename: Arjan
authors.initials: A
authors.lastname: Stegeman
mesh_terms: D000391:Air Microbiology; D000818:Animals; D002645:Chickens; D002988:Cloaca / Q000821:virology; D004391:Dust; D005585:Influenza in Birds / Q000635:transmission* / Q000821:virology*; D009975:Orthomyxoviridae / Q000302:isolation & purification*; D014132:Trachea / Q000821:virology; D017201:Virus Shedding
chemical_list: D004391:Dust