Rat bite fever (also called Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic erythema; Spirillary fever; Sodoku) is an acute, rare disease caused primarily by the bacterium Streptobacillus moniliformis. Spirillum minus causes spirillary rat bite fever in Asia. Rats carry these bacteria but generally do not show any signs of illness. Rat bite fever is transmitted to people in around 10% of rat bites. It can also be transmitted throughout food or water that is contaminated with rat feces or urine. Symptoms like fever, rash, and joint pains usually occur 3-10 days after exposure to an infected rodent, but can be delayed as long as 3 weeks.
Both the spirillary and streptobacillary forms affect mainly people who live in cities in crowded conditions, as well as biomedical laboratory personnel. The actual incidence of the disease is not exactly known as it is under diagnosed. 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. Rat-bite fever is treated with antibiotics (penicillin or tetracyclines for 7-14 days). Doxycycline 100 milligrams every 12 hours for 14 days is an alternative form of treatment. Contamination of water and food by rat excrement must be prevented.