Rabies in rodents and lagomorphs in the United States, 1995-2010.

OBJECTIVE: To assess the epidemiology of rabies in rodents and lagomorphs and provide information that will enable public health officials to make recommendations regarding postexposure prophylaxis for humans after contact with these animals.

DESIGN: Cross-sectional epidemiological analysis.

SAMPLE: Rodents and lagomorphs submitted to state laboratories for rabies diagnosis from 1995 through 2010.

PROCEDURES: Positive samples were identified by use of direct fluorescent antibody testing, typed by sequencing of viral genes, and quantified via titration in mice or cell culture.

RESULTS: 737 rabid rodents and lagomorphs were reported from 1995 through 2010, which represented a 62.3% increase, compared with the number of rabid rodents and lagomorphs reported from 1979 through 1994. The most commonly reported rodents or lagomorphs were groundhogs (Marmota monax). All animals submitted to the CDC for additional viral characterization were positive for the raccoon rabies virus variant. Infectious virus or viral RNA was detected in salivary glands or oral cavity tissues in 11 of 13 rabid rodents.

CONCLUSIONS AND CLINICAL RELEVANCE: The increase in reported rabid rodents, compared with results of previous studies, appeared to be associated with spillover infections from the raccoon rabies epizootic during the first half of the study period. Analysis supported the assumption that rabies remained rare in rodents and lagomorphs. However, transmission of rabies virus via exposure to a rabid rodent or lagomorph may be possible. Given the rarity of rabies in these species, diagnostic testing and consideration of postexposure prophylaxis for humans with potential exposures should be considered on a case-by-case basis.