The History of Avian Medicine in the U.S. II. Pullorum Disease and Fowl Typhoid

Pullorum disease was first recognized in 1899 (in Indiana, by Dr. Leo F. Rettger, later at Yale University). Identification of the causal agent, ultimately named Salmonella pullorum, opened avenues of investigation with far-reaching effects. This discovery of the cause of major mortality in poultry flocks was an important factor in the development of the poultry industry. The development of the avian pathologist was a by-product of research work on pullorum disease during the first few decades following Rettger's finding. The lives of many people were vitally affected. Control of the disease made intensive poultry production possible, profoundly benefiting man through the high-quality proteins so efficiently produced by chickens and turkeys. The disease was first called a fatal septicemia of young chicks. That was soon changed to bacillary diarrhea, shortened by many to BWD. The term white diarrhea, also used for this and other diseases of poultry, caused much confusion in understanding chick diseases of those times. At the second Northeast Conference on Pullorum Disease, in 1929, the term pullorum disease was adopted. The name became internationally accepted following a recommendation by the United States Livestock Sanitary Association at its 1929 meeting. Scattered reports in the lay press indicate that the disease was widespread in the U.S. and elsewhere, and that it was a serious economic problem. Early investigations were carried out largely by Dr. Rettger and his associates and students. In 1909, transmission of this infection through the egg was reported by Drs. Rettger and Stoneburn, representing the first report of egg transmission of any infectious disease. It was not until 1914 that Dr. Rettger and co-workers established the complete cycle of infection and proof that infected chicks could become permanent carriers capable of laying infected eggs. With the advent of commercial hatching, incubator transmission became the most important source of spread of the disease.