Submitted to: American Society for Experimental Biology and Medicine Proceedings
Publication Type: Review Article
Publication Acceptance Date: 11/10/1999
Publication Date: 3/1/2000
Interpretive Summary: Respiratory tract diseases are a leading cause of loss from disease in the cattle, sheep and goat industries. Annual loss in the United States is estimated to exceed one billion dollars. Losses are from mortality, reduced feed efficiency, and slaughter condemnations, as well as prevention and treatment measures. Currently, not all the factors leading to the development of pneumonia are known by scientists and veterinarians. As part of our ongoing studies to understand the disease process, we review the potential role of the Arthus and the Shwartzman reactions in the pathogenesis of pneumonic pasteurellosis. These reactions involve an adverse effect of the immune system that leads to enhanced lesions in the disease. On the basis of our findings, it appears that this would be an important factor in the disease process that may be used to better control shipping fever of cattle. Corollary benefits include an increase in the profitability and international competitiveness of the U. S. cattle industry, a stronger rural economy, and a continued supply of inexpensive, wholesome beef, and beef products for the American consumer.
Technical Abstract: Pneumonic Pasteurellosis (PP) is the most important disease in cattle and is also important in sheep and goats. Pasteurella haemolytica is the bacteria commonly isolated from the severe fibrinopurulent pneumonia that characterizes this respiratory syndrome. Among the pathogenic attributes of the bacteria the leukotoxin (LKT) and the lipopolysaccharide (LPS) are probably the most relevant. Nonetheless, it has been demonstrated that an exacerbated host?s inflammatory response is the main responsible for the lung damage. Despite a lot of research in this field the pathogenesis of pneumonic pasteurellosis is still incomplete. Two classical models of acute inflammatory response, the Arthus reaction and the Shwartzman reaction induced in laboratory animals, provide evidence that both, alone or in combination, could be implicated in the development of the severe lung lesions that characterize PP.