Epidemiology of Salmonellosis in the United States

Salmonellosis has been the subject of many studies throughout the world since Salmon & Smith 1, in 1885, isolated the first member of the genus Salmonella from swine. Little progress was made in the study of these infections in the United States except for pullorum disease in poultry until a few years after White 2, 3 and Kauffmann 4, 5, 6 established the present method of antigenic analysis of the Salmonella group and the occurrence of numerous diverse serotypes were recognized. In 1934, a National Salmonella Center was set up by Dr. P.R. Edwards at the Kentucky Agricultural Experiment Station, Lexington, Kentucky. A few years later (1939), a similar center was started by Dr. F. SCHIFF at Beth Israel Hospital in New York City. In 1947, Dr. Edwards moved the National Center to the Communicable Disease Center, Atlanta, Georgia. Much of the information on the occurrence and distribution of serotypes in this country has resulted from the work of these centers. Summary reports of the work in these laboratories have been published by Edwards et al.7, 8, 9,10, Seligmann et al.11, and Saphra & Winter 12; nearly 45,000 cultures isolated from man, animals, foods and environmental sources were described. During this period, many of the State public health laboratories and some university laboratories began typing cultures they had isolated or those submitted from other laboratories in their areas. As reports of these findings began to appear, it became increasingly obvious that a variety of Salmonella serotypes were widely distributed in the human and animal populations. In a study of 12,331 cultures, Edwards et al.8, reported that types which occurred in both man and animals were recognized in 95% of the cultures from man. These studies emphasized that members of the Salmonella group were widely dispersed; that they were possibly connected in a zoonotic cycle; and that further epidemiological and other studies are required to define the significance and magnitude of the salmonella disease problem in man and animals, and to develop preventive and control measures.