Rat-bite fever (RBF) is an infectious disease caused by two different organisms, Streptobacillus moniliformis and Spirillum minus. In the United States, Rat-bite fever is primarily due to infection with S. moniliformis. Spirillum minus causes Rat-bite fever cases in countries such as Asia and Africa.

Causes

Rat-bite fever refers to an infection which usually develops after having been bitten or scratched by an infected rat. Other rodents (such as mice and gerbils) may also spread the infection to humans.

Sometimes infection can result from handling infected rats, with no reported bite or scratch.

It is also possible to become infected by ingesting food or drink (such as milk or water) contaminated with rat excrement. This form of the disease is sometimes referred to as Haverhill fever.

Risk Factors

Persons who are at risk for infection include those who work with animals in labs or pet stores and persons living in dwellings infested with wild rats. People who have pet rats may also be at risk for infection. Rat-bite fever is NOT transmitted from person to person. You can only get infected from an infected animal, typically through a bite or scratch.

Symptoms

Symptoms usually occur 2-10 days after exposure to an infected animal. Common symptoms include an abrupt onset of chills and fever, vomiting, pain in the back and joints, headache and muscle pain. By this time, the wound itself has usually already healed. Within 2-4 days after the onset of fever, a rash appears on the hands and feet. One or more large joints may then become swollen, red, and painful.

Diagnosis

Please contact your health care provider immediately if you have been in contact with a rat and think you may be experiencing symptoms related to Rat-bite fever. Report your rat exposure to your health care provider.

Treatment

Rat-bite fever can be treated with antibiotics. Treatment is highly effective. Penicillin is the antibiotic of choice. If you are allergic to penicillins, erythromycin may be given to you.

Without treatment, Rat-bite fever due to S. moniliformis , which is found in the United States, can result in extremely serious and potentially fatal complications.

Prevention

• Avoid contact with rats or rat-contaminated dwellings. In addition to Rat-bite fever, contact with rodents, rodent droppings, and dead rodents may result in other infectious diseases.

• If you cannot avoid contact with rats, wear protective gloves, practice regular handwashing and avoid hand-to-mouth contact when handling rats or cleaning rat cages.

• Because you can also get infected with Rat-bite fever after drinking contaminated milk or water, drink pasteurized milk and water from safe sources.

References

CDC