Signs and Symptoms of Rat-bite Fever

Without early diagnosis and appropriate treatment, RBF can cause severe disease and death. In addition to RBF, contact with rodents can result in several other illnesses.

The early symptoms of RBF can be similar to the symptoms of other medical conditions. Symptoms of RBF are often different for the two types of disease: streptobacillary RBF and spirillary RBF (sodoku).

Symptoms and signs of streptobacillary RBF include:

  • Fever
  • Vomiting
  • Headache
  • Muscle pain
  • Joint pain or swelling (about 5 in 10 people with RBF have this)
  • Rash (occurs in about 3 out of 4 people with RBF)
Image of sick women.

Symptoms usually begin 3 to 10 days after contact with the bacteria, but can be delayed as long as 3 weeks. By this time, any rodent bite or scratch wound that caused the infection has usually healed.

Within 2 to 4 days after fever begins, a rash may appear on the hands and feet. This rash looks like flat, reddened areas with small bumps. One or more joints may then become swollen, red, or painful.

The symptoms that develop with Haverhill Fever (the type of infection that can follow after consuming contaminated food or water) are similar to streptobacillary RBF, but may include more severe vomiting and sore throat.

Complications of streptobacillary RBF can include:

  • Abscesses (pockets of infected fluid) inside of the body, like in the belly (abdominal cavity)
  • Infections of the liver (hepatitis) and kidneys (nephritis)
  • Infections involving the lung (pneumonia)
  • Infections involving the brain and nervous system (meningitis)
  • Infections involving the heart (endocarditis, myocarditis, or pericarditis)

About 1 in 10 people who have streptobacillary RBF infection die.

Symptoms and signs of spirillary RBF (sodoku) can vary and often include:

  • Fever (that may come and go or occur repeatedly)
  • Swelling or formation of an ulcer at the bite wound (if present)
  • Swollen lymph nodes (small glands that filter lymph, the clear fluid that circulates through the lymphatic system, and help fight infections)
  • Rash (about 5 in 10 people with sodoku have this) that can appear all over the body or only near the area of the bite wound (if present)

These symptoms usually occur 7-21 days after exposure to an animal carrying the bacteria.

If you have any of the symptoms of RBF after contact with rats or other rodents, immediately see your health care provider. Make sure to tell your provider about your contact with rodents.