Experimental aerosol transmission of Actinobacillus pleuropneumoniae to pigs.
In order to demonstrate the possible role of aerosol in the transmission of Actinobacillus pleuropneumoniae, an experiment including 18 specific pathogen-free (SPF), 10-week-old piglets, randomly distributed into 2 adjacent units, was carried out. In these facilities, air was forced through absolute filters to prevent any contact with infectious agents. During the first 6 d post inoculation, the 2 units were connected by a rectangular opening and the air circulation was forced by the ventilation system from unit A (inoculated pigs) to unit B (non-inoculated pigs). The A. pleuropneumoniae strain (biovar 1 serovar 9) was isolated in France from an outbreak of porcine pleuropneumonia. Two different infecting doses, 10(7) cfu/animal and 10(8) cfu/animal, were inoculated by intranasal route in 6 pigs of unit A. The infection spread quickly from the inoculated pigs to the non-inoculated pigs. Clinical signs were acute during the 4 d post inoculation: hyperthermia, respiratory distress and, sometimes, death (6 pigs of the unit A and 2 pigs of the unit B). All pigs seroconverted against A. pleuropneumoniae serovar 9 within 2 weeks. Lung lesions were severe: fibrinous pleurisy and lung hemorrhages in the acute stage, pleural adherences and focal pulmonary necrosis in the chronic stage. Actinobacillus pleuropneumoniae was isolated from the tonsils and/or lungs in 16 animals. It could be also isolated from the air of the experimental unit. This study showed that A. pleuropneumoniae was readily transmitted through aerosol over a distance of at least 2.5 m.
Jobert
J L
JL
Agence Française de Sécurité Sanitaire des Aliments, Zoopôle, Ploufragan, France. jl.jobert@ploufragan.afssa.fr
Savoye
C
C
Cariolet
R
R
Kobisch
M
M
Madec
F
F
D000189:Actinobacillus Infections / Q000635:transmission / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000472:pathogenicity*; D000336:Aerosols; D000818:Animals; D004196:Disease Outbreaks / Q000662:veterinary; D018562:Disease Transmission, Infectious / Q000662:veterinary; D019570:Inhalation Exposure; D013552:Swine; D013553:Swine Diseases / Q000635:transmission*
D000336:Aerosols