Definition of Rat-bite fever:

Rat-bite fever is a rare disease spread by infected rodents.

Causes, incidence, and risk factors:

Rat-bite fever can be caused by the bacteria, Actinobacillus muris (formerly called Streptobacillus moniliformis) and Spirillum minus. Most cases of rat-bite fever occur in Japan, where it is called sodoku.

The disease has also been seen in:

• Africa
• Australia
• Europe
• North and South 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:

• Chills
• Fever
• Headache
• Muscle aches
• Open sore at the site of the bite in sodoku
• Rash -- may be red/purple plaques in sodoku
• Swollen, red, and painful joints (not usually seen in sodoku)

Signs and tests:

This condition is diagnosed by detecting the bacteria in skin, blood, joint fluid, or lymph nodes. Blood antibody tests may also be used.

Treatment:

Rat-bite fever is usually treated with antibiotic therapy. Your health care provider may prescribe penicillin or tetracyclines for 7-14 days.

Expectations (prognosis):

The outlook is excellent with early treatment.

Complications:

• Abscesses of the brain or soft tissue
• Endocarditis
• Infection of the heart valves
• Inflammation of the parotid glands (parotitis)
• Inflammation of the tendons (tenosynovitis)
• Pericarditis

Calling your health care provider:

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

Prevention:

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.