Rabies Prophylaxis for Rat Bites
Rabies vaccination is NOT necessary for rat bites, as small rodents (including rats, mice, squirrels, hamsters, guinea pigs, gerbils, chipmunks, rabbits, and hares) are almost never found to be infected with rabies and have not been known to transmit rabies to humans in the United States. 1
Risk Assessment for Rodent Bites
- Small rodents and lagomorphs (rabbits and hares) almost never require rabies postexposure prophylaxis. 1
- The epidemiologic evidence demonstrates that these animals do not serve as rabies reservoirs and transmission from these species to humans has not been documented. 1
- In contrast to rats, bites from wild carnivorous mammals (skunks, raccoons, foxes, coyotes, bobcats) or bats should be considered rabid unless proven otherwise and require immediate postexposure prophylaxis. 1, 2
Appropriate Wound Management for Rat Bites
Even though rabies prophylaxis is not indicated, proper wound care remains essential:
- Immediately irrigate the wound thoroughly with copious amounts of water or normal saline solution for at least 15 minutes with soap and water. 3, 4
- This mechanical cleansing alone markedly reduces the risk of bacterial infection, which is the primary concern with rodent bites. 3, 2
- Assess tetanus vaccination status and administer Tdap if not vaccinated within the last 10 years (or 5 years for contaminated wounds). 3
- Consider antibiotic prophylaxis (amoxicillin-clavulanate as first-line) for high-risk wounds, particularly if the wound is on the hand, involves deep puncture, or the patient is immunocompromised. 3
When Rabies Prophylaxis IS Required
For comparison, rabies postexposure prophylaxis (both vaccine and immunoglobulin) is indicated for:
- Category III exposures: any penetration of skin by teeth from high-risk animals (bats, wild carnivores), contamination of mucous membranes with saliva, or licks on broken skin. 2
- Previously unvaccinated persons require Human Rabies Immune Globulin (HRIG) 20 IU/kg infiltrated around the wound plus 5 doses of rabies vaccine on days 0,3,7,14, and 28. 1, 2
- Previously vaccinated persons require only 2 doses of vaccine on days 0 and 3, without immunoglobulin. 2
Common Pitfall to Avoid
The critical error would be administering unnecessary rabies prophylaxis for rodent bites, which exposes patients to needless cost, inconvenience, and potential adverse effects when the epidemiologic risk is essentially zero. 1