Rat-bite fever (RBF) is an infectious disease that can be caused by two different bacteria. Streptobacillary RBF is caused by Streptobacillus moniliformis in North America while spirillary RBF or sodoku is caused by Spirillum minus in Asia. People usually get the disease from infected rodents or consumption of contaminated food or water. The majority of cases are due to rodent bite. Rat bite fever is transmitted to people in around 10% of rat bites. There are only 1-2 cases of rat-bite fever per year in the UK. People who keep rats as pets, laboratory technicians and pet shop employees working with rats, are at increased risk.
Symptoms depend on the bacteria that caused the infection and include rash, recurrent fever, chills, and joint pain. Symptoms usually occur 3-10 days after exposure to an infected rodent, but can be delayed as long as 3 weeks. RBF is diagnosed by isolating S. moniliformis from blood, synovial fluid, or other body fluids. Rat-bite fever is treated with antibiotics (penicillin or tetracyclines for 7-14 days). Erythromycin 500 milligrams might be administered to people who are allergic to penicillin.