Changing epidemiologic aspects of typhoid fever in California.

Typhoid fever in California is no longer a major public health problem. The previously high incidence of water- and milk-borne infections has been greatly reduced. Human carriers now are the source of most infections. Chloramphenicol has proven to be a valuable aid in the therapy of the acutely ill patient, but it has not as yet solved the therapeutic or public health problems of typhoid fever. It continues to be vital for the protection of the public that every suspected case of typhoid fever be definitely established by appropriate public health laboratory procedures, that thorough investigation be carried out to determine the source of infection, and that careful follow-up examinations be done so that if a carrier state develops, proper measures can be taken.