Condition 101 About Rat-Bite Fever

What is the definition of Rat-Bite Fever?

Rat-bite fever is a rare bacterial disease spread by the bite of an infected rodent.

What are the alternative names for Rat-Bite Fever?

Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic erythema; Spirillary fever; Sodoku

What are the causes for Rat-Bite Fever?

Rat-bite fever can be caused by either of two different bacteria, Streptobacillus moniliformis or Spirillum minus. Both of these are found in the mouths of rodents.

The disease is most often seen in:

  • Asia
  • Europe
  • North America

Most people get rat-bite fever through contact with urine or fluids from the mouth, eye, or nose of an infected animal. This most commonly occurs through a bite or scratch. Some cases may occur simply through contact with these fluids.

A rat is usually the source of the infection. Other animals that may cause this infection include:

  • Gerbils
  • Squirrels
  • Weasels

What are the symptoms for Rat-Bite Fever?

Symptoms depend on the bacteria that caused the infection.

Symptoms due to Streptobacillus moniliformis may include:

  • Chills
  • Fever
  • Joint pain, redness, or swelling
  • Rash

Symptoms due to Spirillum minus may include:

  • Chills
  • Fever
  • Open sore at the site of the bite
  • Rash with red or purple patches and bumps
  • Swollen lymph nodes near the bite

Symptoms from either organism usually resolve within 2 weeks. Untreated, the symptoms, such as fever or joint pain, can keep returning for many weeks or longer.

What are the current treatments for Rat-Bite Fever?

Rat-bite fever is treated with antibiotics for 7 to 14 days.

What is the outlook (prognosis) for Rat-Bite Fever?

The outlook is excellent with early treatment. If it is not treated, the death rate can be as high as 25%.

What are the possible complications for Rat-Bite Fever?

Rat-bite fever may cause these complications:

  • Abscesses of the brain or soft tissue
  • Infection of the heart valves
  • Inflammation of the parotid (salivary) glands
  • Inflammation of the tendons
  • Inflammation of the heart lining

When should I contact a medical professional for Rat-Bite Fever?

Call your 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

How do I prevent Rat-Bite Fever?

Avoiding contact with rats or rat-contaminated dwellings may help prevent rat-bite fever. Taking antibiotics by mouth promptly after a rat bite may also help prevent this illness.


Shandro JR, Jauregui JM. Wilderness-acquired zoonoses. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 34.

Washburn RG. Rat-bite fever: Streptobacillus moniliformis and Spirillum minus. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 233.

Latest Advances On Rat-Bite Fever

There is no recent research available for this condition. Please check back because thousands of new papers are published every week and we strive to find and display the most recent relevant research as soon as it is available.

Clinical Trials For Rat-Bite Fever

Clinical Trial
  • Status: Active, not recruiting
  • Phase: N/A
  • Intervention Type: Behavioral
  • Participants: 32
  • Start Date: May 1, 2020
Preventing Cognitive and Functional Decline Among Seniors at Risk-Effects of Online Training Aimed at Increasing Participation in Everyday Life During a Pandemic.
Clinical Trial
  • Status: Active, not recruiting
  • Phase: N/A
  • Intervention Type: Behavioral
  • Participants: 232
  • Start Date: November 2, 2017
Preventing Cognitive and Functional Decline Among Seniors at Risk: A Community-Based Randomized Trial