Studies of pleuropneumonia-like organisms

The occurrence of a great number of poultry diseases which affect the respiratory systems of both chickens and turkeys has brought about extensive studies on control measures to curb losses due to these infections. The losses due to these infections are tremendous throughout the poultry producing areas of the world. Infectious laryngotracheitis, Newcastle disease, fowl pox, infectious bronchitis, chronic respiratory disease, infectious sinusitis, fowl cholera and aspergillosis cause similar symptoms and gross lesions (19). Diagnosis and preventive treatment are of extreme importance. Fowl cholera and aspergillosis can be detected by cultural techniques. The other six diseases show differential diagnosis with histological examination of lungs, trachea and air sacs. The respiratory diseases; chronic respiratory disease in chickens (CRD) and infectious turkey sinusitis (ITS) are of prime importance. There is a report of 90-100 per cent mortality in one flock of 800 birds (13); with two more examples of 100 per cent mortality in flocks of 500 birds (13); with two more examples of 100 per cent mortality in flocks of 500 birds each (16). The greatest losses have been reported in weight loss, loss of egg production, and of fertility in breeder stock (14, 16, 26). J.E. Prier (31) found in overall studies of IT’S A morbidity of 25 per cent and with low mortality. McDowell (20) estimated for the 1951 Delmarva production of 167,000,000 broilers, an average loss of six per cent above normal or 10,000,000 birds.The purpose of these experiments were to check the effect of Aureomycin in the diet of chickens as a possible control measure against CRD, and to study the methods of isolation and culturing of the agent or agents involved