Rat-bite fever

Rat-bite fever is a rare but serious bacterial infection that people can get after being bitten or scratched by an infected rodent, or sometimes just by handling rodents or consuming food or water contaminated with rodent droppings. It is caused by two different bacteria: Streptobacillus moniliformis (the most common cause in North America and Europe) and Spirillum minus (more common in Asia). The form caused by Spirillum minus is sometimes called Sodoku. Despite the name, you do not always need to be bitten by a rat — mice, gerbils, squirrels, and other rodents can also spread the infection. Once the bacteria enter the body, they can spread through the bloodstream and cause a range of symptoms. Most people develop a sudden fever, chills, headache, muscle aches, and a rash, usually within a few days to three weeks after exposure. Joint pain and swelling are also very common, especially with the Streptobacillus form. If left untreated, the infection can spread to the heart, brain, or other organs and become life-threatening. The good news is that rat-bite fever responds well to antibiotics. Penicillin is the standard first-line treatment, and most people recover fully when the infection is caught and treated early. Doxycycline or amoxicillin are used as alternatives. Early diagnosis is key, because the disease can be mistaken for other illnesses, and delays in treatment can lead to serious complications.

Inheritance

Sporadic

Usually appears on its own, not inherited from a parent

Age of Onset

Variable

Can begin at different ages, from infancy through adulthood

Data is compiled from FDA regulatory filings and ClinicalTrials.gov, then processed through automated extraction; event classifications and dates may occasionally be misclassified. Verify against the linked FDA filing or trial record before clinical decisions. Updated periodically.

Source: openFDA + DailyMed · NDA / BLA labels with structured indications · refreshed weekly

Source: ClinicalTrials.gov · synced daily · phases, status, and PI names normalized at ingest

Source: NPI Registry + PubMed · trial PI roles cross-referenced with ClinicalTrials.gov · ranked by match score (publications + PI activity + community signal)

Source: NORD Rare Disease Centers + NIH Undiagnosed Diseases Network (UDN) · centers verified active within last 12 months

Source: PubMed + NIH RePORTER + openFDA + clinical-journal RSS · last 30 days · disease-tagged at ingest by AI extraction with human QC

Bring these to your next appointment

• Q1.How do I know if my infection has spread beyond the bloodstream, and what tests will check for this?,How long do I need to take antibiotics, and what happens if I miss a dose?,What symptoms should prompt me to go to the emergency room during my recovery?,Is it safe to keep my pet rodent, and how can I reduce the risk of this happening again?,Do I need any follow-up tests to confirm the infection is fully gone?,Are there any long-term complications I should watch for after recovery?,Should other people in my household be tested or treated if they also had contact with the rodent?

Common questions about Rat-bite fever

Related conditions

Other rare diseases commonly researched alongside Rat-bite fever.

• Leptospirosis→
• Lyme disease→
• Tularemia→