Rat-bite fever is a rare acute infectious disease caused by two different bacteria, Streptobacillus moniliformis and Spirillum minus. People usually get the disease from infected rodents or consumption of contaminated food or water. Rat bite fever is transmitted to people in around 10% of rat bites. In America and Europe, rat bite fever is usually due to S.moniliformus, while in Asia it is usually due to S.minus. Both the spirillary and streptobacillary forms affect mainly people who live in cities in crowded conditions, biomedical laboratory personnel and children with rats as pets.
Symptoms chills, recurrent fever, joint pain, rash, open sore at the site of the bite, swollen lymph nodes near the bite. Rash may be red or purple. 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 the bacteria from blood, synovial fluid, or other body fluids. Treatment involves administration of amoxicillin 1 g per oral, procaine penicillin G 600,000 units IM every 12 hours, or penicillin V 500 milligrams per oral for 7 to 10 days. Erythromycin 500 milligrams might be administered to people who are allergic to penicillin.