title: Cloacal infection with Mycoplasma gallisepticum and the effect of inoculation with H120 infectious bronchitis vaccine virus.
abstract: Infectivity of an isolate of Mycoplasma gallisepticum of low virulence was studied in specific pathogen free chickens from 1 day old until after the onset of lay. Widespread cloacal infection developed and it was discussed in relation to the low serological response. The effects produced by inoculation of H120 infectious bronchitis vaccine virus and coming into lay were associated with changes in serological response and increased cloacal cultural recovery. The possibility of ascending cloacal infection giving rise to egg transmission was considered and compared with other routes whereby ovules may become infected.
authors.affiliation: Fisheries and Food Veterinary Laboratory, Ministry of Agriculture, Lasswade, Scotland.
authors.forename: K J
authors.initials: KJ
authors.lastname: Macowan
authors.forename: C J
authors.initials: CJ
authors.lastname: Randall
authors.forename: T F
authors.initials: TF
authors.lastname: Brand