Abstract
An experimental Bordetella bronchiseptica infection was carried out by usingcolostrum-fed conventional piglets at 5 or 6 days of age. They were inoculated intra-nasally with either B. bronchiseptica culture or emulsified suspension of turbinate bonefrom a naturally infected pig, and subjected to bacteriological, serological and pathological examinations. The results obtained are as follows.Clinical signs were seen in all the infected piglets though transiently. B. bronclziseptica became established within a week after instillation into the nasal cavities of thepiglets, being undetectable at 22 to 23 weeks of age. The titers of maternal antibodies ittpiglets were shown to be l : 320 at 5 days of age, declining l : 10 or less at 8 weeks ofage when a significant immune response to B. bronchiseptica infection became detectable.At autopsy, turbinate atrophy was observed macroscopically in only 5 of 10 pigletsinoculated with B. bronchiseptica.No specific nasal lesion was produced irn piglets inoculated with an emulsified suspen-sion of turbinate bone from a naturally infected piglet containing no Bordetellaorganisms.Within a week after exposure to carrier animals, B. bronchiseptica became establishedin the nasal cavities of 13- to 18-week-old piglets, showing significant antibody titers butno turbinate atrophy.
