Rat-Bite Fever in the United States: An Analysis Using Multiple National Data Sources, 2001-2015.

Background: Rat-bite fever is a rare disease associated with rat bites or direct/indirect rodent contact.

Methods: We examined rat-bite fever and rat-bite injury diagnoses in the United States during 2001-2015. We analyzed national, state, and Indian Health Service healthcare encounter datasets for rat-bite fever and rat-bite injury diagnoses. We calculated average-annual encounter rates per 1 000 000 persons.

Results: Nationally, the rat-bite fever Emergency Department visit rate was 0.33 (95% confidence interval [CI], 0.19-0.47) and the hospitalization rate was 0.20 (95% CI, 0.17-0.24). The rat-bite injury Emergency Department visit rate was 10.51 (95% CI, 10.13-10.88) and the hospitalization rate was 0.27 (95% CI, 0.23-0.30). The Indian Health Service Emergency Department/outpatient visit rate was 3.00 for rat-bite fever and 18.89 for rat-bite injury. The majority of rat-bite fever encounters were among individuals 0-19 years of age.

Conclusions: Our results support the literature that rat-bite fever is rare and affects children and young adults. Targeted education could benefit specific risk groups.