Salmonella and Paracolon species isolated from the wild brown rat, Rattus norvegicus, in the city of Richmond, Virginia

The importance of bacteria as a cause of serious intestinal diseases in man and. other animals has been recognized since the early days of the science of bacteriology. Of those forms usually associated with intestinal disturbances in man, the species considered most important are those belonging in the Salmonella group, the Paracolon group, and the Shigella group. Also, it has been known since the early part of this century that the conman rat serves as an important vector for the dissemination of infectious organisms. For example, standard textbooks list rats as primary vectors of enteric bacteria. However. there has been a surprisingly small amount of work done to determine the actual percentage of infection in wild rats. There have been numerous investigations concerning outbreaks of Salmonellosis in mouse populations, and in mouse colonies in breeding laboratories, but few surveys have been made on wild rodents in recent years