Rabies Transmission Risk from Rats
Small to medium-sized rats are extremely unlikely to transmit rabies virus and have not been documented to cause rabies in humans in the United States. 1
Risk Assessment for Rat Bites
Rats pose negligible rabies transmission risk and postexposure prophylaxis is almost never indicated. 2
- Small rodents including rats, mice, squirrels, hamsters, guinea pigs, gerbils, and chipmunks are almost never found to be infected with rabies 1
- No documented cases of rabies transmission from rats to humans have been reported in the United States 1
- From 1990-1996 in areas with endemic raccoon rabies, woodchucks (groundhogs) accounted for 93% of the 371 rabies cases among all rodents, with rats not significantly represented in these statistics 1
- Even in the most recent surveillance data from 2011-2020, groundhogs and beavers constituted 97% of all rodent rabies cases, with percent positivity in most rodents remaining <2.5% 3
Management Algorithm for Rat Bites
Immediate Wound Care (Required for ALL rat bites)
- Thoroughly wash and flush the bite wound with soap and water for 15 minutes 4, 2
- Apply a virucidal agent such as povidone-iodine solution to the wound after washing 4, 5, 2
- Assess need for tetanus prophylaxis 4
- Consider antibiotic prophylaxis for bacterial infection, particularly rat bite fever, which is a more significant concern than rabies 4
Rabies Prophylaxis Decision
- Rabies postexposure prophylaxis is NOT recommended for rat bites 2
- The FDA drug label for rabies immune globulin explicitly states: "Bites from squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, other small rodents, rabbits, and hares almost never require antirabies post-exposure prophylaxis" 2
- Consult state or local health department before initiating prophylaxis in the rare circumstance where unusual behavior or other factors raise concern 1, 2
Critical Distinction from High-Risk Species
Do not confuse rat bite management with bites from high-risk rabies reservoir species: 5
- Wild carnivores (raccoons, skunks, foxes, coyotes) require immediate rabies prophylaxis 1, 2
- Bats are documented rabies reservoirs in all 49 continental states and require different management with a much lower threshold for prophylaxis 1, 5, 2
- Domestic dogs and cats require case-by-case evaluation based on regional epidemiology and vaccination status 1, 2
Common Pitfall to Avoid
The primary clinical concern with rat bites is bacterial infection (rat bite fever), not rabies. 4 Healthcare providers should focus on appropriate wound care, tetanus prophylaxis, and antibiotic coverage rather than rabies prophylaxis, which creates unnecessary patient anxiety and healthcare costs for an essentially non-existent risk.