Effects of high and low environmental temperatures on clinical course of fowl cholera in turkeys.

Turkeys inoculated with Pasteurella multocida either in the palatine air spaces or via drinking water were maintained t high (33.4-37.4 C), low (2.6-5.3 C), and moderate (19.8-22.4 C) temperatures in temperature-controlled chambers to determine the influence environmental temperature had on the pathogenesis of fowl cholera. In inoculated turkeys maintained at high temperatures, there was a delay in the onset of depression and, in most instances, in mortality in relation to those at low or moderate temperatures. In turkeys inoculated via drinking water and maintained at low temperatures, there was a higher mortality than in those at high or moderate temperatures. In turkeys maintained at low temperatures during the preinoculation period, the onset of depression was accelerated more after inoculation than in those maintained at moderate temperatures before inoculation. The percentage of leukocytes in the hematocrit was higher in turkeys inoculated int he palatine air spaces and maintained at low temperatures than in turkeys similarly inoculated but maintained at high or moderate temperatures. Cloacal temperatures were higher in all inoculated turkeys maintained at high temperatures than in those at low or moderate temperatures, and decreased markedly when turkeys became moribund. In turkeys inoculated in the palatine air spaces, deaths from pneumonia occurred more frequently at low temperatures and torticollis occurred more frequently at high temperatures than at the other temperatures.