Rat bite fever (also called Streptobacillary fever, Streptobacillosis, Haverhill fever, Epidemic arthritic erythema; Spirillary fever; Sodoku) is an acute, rare disease caused by bacteria Streptobacillus moniliformis and Spirillum minus. Rats are carriers of both bacteria but rarely show signs of illness. 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. Higher risk groups include laboratory workers, the owners of pet rats, pet shop personnel and veterinarians, as well as people who are exposed to wild rats.
Symptoms due to S. moniliformis may include chills, fever, joint pain, redness, or swelling and due to S. minus may include chills, fever, open sore at the site of the bite, rash may be red/purple, plaques, swollen lymph nodes near the bite. Symptoms usually occur 3-10 days after exposure to an infected rodent, but can be delayed as long as 3 weeks. Rat-bite fever is treated with antibiotics (penicillin or tetracyclines for 7-14 days). Alternative drugs include ampicillin, cefuroxime, and cefotaxime. People handling rats or clean their cages should be advised to wear protective gloves, wash their hands after contact, and avoid hand-to mouth contact.