Simple fibrinous pneumonia is likely to arise from climatic conditions or from exposure, attacks several at once and none later, has less abrupt rise of temperature, less tenderness of the chest walls, less dyspnœa, less obstinate standing, and after death, less interlobular exudate and marbling, and no presentation of old and recent lesions in the same lung.
In the infectious pneumonia occasionally seen in western cattle, the distinction must be made mainly by the less elevated temperature, less dyspnœa, the lack of the early signs of extensive consolidation of the affected lung, and after death, absence of the extensive interlobular infiltration, and in the predominance of the whitish points or mottling indicating the broncho-pneumonia and the cell proliferation in the terminal bronchia and alveoli.
The pulmonary form of hæmorrhagic septicæmia (Wildeseuche) is distinguished by its enzoötic character, in connection with wet lands, its occurrence in the summer season, its association with other forms of localization, in the abdomen, muscular system, etc., its dependence on a cocco-bacillus, easily found in the exudate, and its inoculability on the smaller ruminants, horses, pigs and rodents.
The perforation of lungs and heart by a sharp pointed foreign body from the reticulum, occurs sporadically in one animal which has usually been kept indoors; it shows as a rule less fever, may be preceded by tympany or other gastric trouble, shows a line of consolidation from the reticulum forward, is earlier or later complicated by morbid heart sounds or rhythm, and commonly shows a pitting swelling beneath and beside the sternum.
Pulmonary emphysema is sporadic only, usually devoid of sudden hyperthermia, or constitutional disorder, has a dry paroxysmal cough, wheezing sounds on auscultation, and a drumlike sound on percussion. If associated with bronchitis or pneumonia and attendant fever, the case is more equivocal.
Aspergillosis of the Lung usually advances more slowly, in the comparative absence of sudden hyperthermia, shows more limited areas of consolidation, less dyspnœa, and usually affects smaller animals (birds) as well. At the necropsy the presence of aspergillus in bronchia and lung tissue is conclusive.
The acute pulmonary congestion of heat stroke is sufficiently identified by the conditions under which it occurs, its sudden and rapid progress, the implication of the brain, and its occurrence in other animals similarly exposed.
Such conditions as atelectasis, pulmonary actinomycosis, distomatosis, or echinococcus, the congestion of mercurialism, etc., should be readily recognized by the attendant conditions, analysis or necropsy.
Attempts have been made to diagnose lung plague by securing a reaction, local or general, as the result of injection of the sterilized lung exudate or cultures, but they have proved eminently unreliable. The susceptibility of the serum to change under manipulation, the existence of hyperthermia before the injection, and the disposition to local infiltration under the lung plague poison are apparently insuperable obstacles.
Treatment. No treatment has been devised that would warrant the preservation of the infected animals when the alternative of prevention is available. The question is an economic one, and with a disease that is so insidious, with such a long incubation, with so many occult and chronic cases liable to escape observation and recognition, and with such a constant and prolonged exhalation from the lungs of the virulent material and the certainty almost of the diffusion and preservation of the latter, no more suicidal policy could be adopted than the preservation and treatment of the sick.