For 2300 years, illness associated with rat bites has been recognized in India, which is believed to be the country of origin for the disease. The first recorded description of rat-bite fever was in lectures by a physician at Yale in the early nineteenth century. It was not until 1902 that Japanese workers describing the clinical entity in a European journal coined the term “Rattenbisskrankheit,” or rat-bite fever. Rat-bite fever comprises two clinically similar but distinct bacterial diseases, caused by two unrelated agents, Streptobacillus moniliformis and Spirillum minus. The organisms are distributed worldwide, with S. moniliformis more common in the United States and Europe, and S. minus more common in the Far East.

Rat-bite fevers are most frequently associated with the bite or, less frequently, a scratch or direct contact (e.g., child kissing pet rat) with pet, wild, or laboratory rats. A number of reported cases were not associated with rat bites or contact, although all patients had a history of occupational exposure to rat-infested areas or contaminated materials. Disease caused by these agents has also followed contact with a variety of other species, including mice, gerbils, guinea pigs, squirrels, dogs, cats, ferrets, turkeys, and weasels, all of which presumably had contact with rats or contaminated materials. Estimates are that 2 million animal bites occur annually in the United States of which ~1% are caused by rats. Many cases of rat-bite fever occur in individuals of low socioeconomic status in cities or, with increasing frequency, in association with pet rats, whose popularity is increasing. Rats are also often fed to pet snakes and other reptilians with cases of rat-bite fever described in their owners. Asymptomatic rats are the principal reservoirs for the organisms that reside as commensals in the nasopharynx, middle ear, and proximal trachea.