The fate of Pasteurella multocida after intratracheal inoculation into turkeys.

Young adult turkeys were intratracheally inoculated with the P-1059 strain of Pasteurella multocida, and the fate of the organism was studied by quantifying the organism in various respiratory and systemic tissues at various times after the inoculation. The results showed that, in the first 2 h, on the order of 10(8) to 10(9) organisms deposited at the upper trachea multiplied in situ to gradually spread downwards to the lower respiratory tract. In the majority of turkeys, by 6 h postinoculation the organism invaded the circulatory system and multiplied vigorously in the liver and spleen. In some birds, however, the organism appeared to have reached the liver from the trachea instantaneously by an unidentified mechanism. Vaccination with inactivated vaccines protected turkeys from intratracheal challenge exposure, as well as from intramuscular inoculation.