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Rat-bite fever is a rare disease spread by infected rodents.
Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic erythema; Spirillary fever; Sodoku
Rat-bite fever can be caused by two different bacteria, Streptobacillus moniliformis or Spirillum minus, both of which are found in the mouths of rodents.
The disease is most often seen in:
- North America
Most people get rat-bite fever through contact with urine or secretions from the mouth, eye, or nose of an infected animal. This most commonly occurs though a bite, yet some cases may occur simply through contact with these secretions.
The source of the infection is usually a rat. Other animals that may cause infection include squirrels, weasels, and gerbils.
Symptoms depend on the bacteria that caused the infection.
Symptoms due to Streptobacillus moniliformis may include:
- Joint pain, redness, or swelling
Symptoms due to Spirillum minus may include:
- Open sore at the site of the bite
- Rash -- may be red/purple plaques
- Swollen lymph nodes near the bite
Exams and Tests
This condition is diagnosed by detecting the bacteria in skin, blood, joint fluid, or lymph nodes. Blood antibody tests and polymerase chain reaction (PCR) techniques may also be used.
Rat-bite fever is treated with antibiotics. Your health care provider may prescribe penicillin or tetracyclines for 7 - 14 days.
The outlook is excellent with early treatment. Untreated, the death rate can be as high as 25%.
When to Contact a Medical Professional
Call your health care provider if:
- You or your child has had recent contact with a rat or other rodent
- The person who was bitten has symptoms of rat-bite fever
Avoiding contact with rats or rat-contaminated dwellings may help prevent rat-bite fever. Taking antibiotics by mouth after a rat bite may also help prevent this illness.
Washburn RG. Rat-bite fever: Streptobacillus moniliformis and Spirillum minus. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 231.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.