Rat Bite Fever: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Rat Bite Fever?
A primary care doctor, such as a family medicine or internal medicine doctor, usually treats rat bite fever. If the infection is severe or has spread, an infectious disease specialist may be brought in, and a hospital team may be involved for people needing intravenous medicine.
What it is
Rat bite fever is a bacterial infection that people can get after contact with rats or, less often, other rodents. Two different bacteria can cause it: Streptobacillus moniliformis and Spirillum minus. The illness is usually treatable with antibiotics, but without treatment it can become serious.
Symptoms
Symptoms usually start within days to weeks after a rat bite or scratch. The most common signs are fever, chills, headache, vomiting, and muscle pain, often with a rash of small red or purple bumps on the hands and feet. Joint pain and swelling can happen too, and with the Spirillum form, the wound may reopen and nearby lymph nodes may swell.
Causes and who gets it
The bacteria live in the mouths and noses of healthy rats. People usually get infected through a bite or scratch, but also by handling an infected rat or contacting its saliva, and rarely by drinking contaminated unpasteurized milk. Pet owners, people who work with rodents, and those living in buildings with rat problems face higher exposure, and children are commonly affected.
How doctors diagnose it
There is no single quick test, so doctors start by asking about any contact with rats or other rodents. A physical exam, blood tests, and sometimes lab samples from the wound or joint fluid can help confirm the infection. Because the illness can look like other infections, doctors may run tests to rule out other causes.
Treatment
Rat bite fever is treated with antibiotics, and most people improve with medicine taken by mouth. People with more severe illness may need antibiotics through a vein at a hospital. Treated early, most people recover well; untreated, the infection can spread to the heart, brain, lungs, or other organs.
When to see a doctor
Anyone with fever, rash, or joint pain after a rat bite, scratch, or close contact with rodents should see a doctor soon. Even a bite that seems to heal can lead to infection days or weeks later. High fever, confusion, trouble breathing, or severe headache requires immediate medical care.
How a direct primary care or concierge doctor fits in
A direct primary care doctor, who charges a flat monthly fee instead of billing insurance, can often manage this problem directly. A concierge doctor, who usually charges more and often works alongside insurance, can also manage it. They can examine the bite, order lab tests, and prescribe antibiotics, referring to a specialist if needed. One benefit of these practices is easier access when symptoms appear.
Common questions
Can you get rat bite fever without being bitten?
Yes. Infection can happen after a scratch, after handling an infected rat, or through contact with the animal's saliva, even without an obvious wound.
How soon after a rat bite do symptoms appear?
With the Streptobacillus form, symptoms usually appear within 3 to 10 days. The Spirillum form often takes one to four weeks.
Can pet rats carry the bacteria?
Yes. Even rats bred as pets can carry the bacteria without looking sick. Washing hands after handling rodents lowers the risk.
Sources
- MedlinePlus - Legionnaires disease
- Centers for Disease Control and Prevention - About Rat Bite Fever (RBF) | Rat-bite Fever (RBF)
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
