Rat bite fever (Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic erythema; Spirillary fever; Sodoku) is an acute, rare disease caused by Streptobacillus moniliformis and Spirillum minus. In America and Europe, rat bite fever is usually due to S. moniliformus, while in Asia it is usually due to S. minus. Rats are carriers of both bacteria but rarely show signs of illness. Disease has been reported in mice, birds, guinea pigs, and nonhuman primates. The majority of cases are due to the animal's bite. It can also be transmitted throughout food or water that is contaminated with rat feces or urine.
Symptoms depend on the bacteria that caused the infection and the include fever, chills, rash and polyarthritis. Rat bite fever is diagnosed by detecting the bacteria in skin, blood, synovial fluid, or lymph nodes. It can be treated readily with antibiotics (pencillin and tetracycline), but untreated S. moniliformis infections are estimated to be fatal and causes complications like infection of the brain or soft tissue, infection of the heart valves, inflammation of the parotid glands, the tendons and the heart lining. Ampicillin, cefuroxime, and cefotaxime can be used in patients allergic to penicillin.