Fig 5.

Experimental design of direct and indirect contact transmission experiment. Two pens, indicated as pen A and pen B, were placed 18 inches apart in one isolator room in a BL2 barn facility. Two pigs were intranasally inoculated with the B. bronchiseptica strain tested, placed in pen A, and served as primary-challenged pigs, indicated by “P.” After 2 days, three naïve pigs, serving as a direct contacts, indicated by “D,” were added to pen A, and five naïve pigs were placed in pen B, serving as indirect contacts, indicated by “I.” Nasal colonization of all pigs was monitored by periodical nasal swabbing, and necropsy of all pigs was performed on day 25.