Exposure to rodents and lagomorphs has never been implicated as the cause of infection for a case of rabies in humans in the United States, nor are these animals considered natural reservoirs of the disease.1 However, the number and reliability of such reports are limited, and there is concern about rabies in rodents and lagomorphs. Reliable reports of human exposure to rabid rodents or lagomorphs outside of the United States are limited.2 Many suspect rodents and lagomorphs are tested each year for rabies, and a small but increasing number are found to be rabid.3 Although they represent a low risk for rabies virus transmission, rodents and lagomorphs may contribute to possible rabies virus exposure in humans, domestic animals, and other wildlife.1 In addition, because of the close cohabitation of some rodent species with human populations and the high incidence of rodent bites, public health officials are frequently asked to evaluate the need for rabies PEP after human contact with these animals.3
Northeastern and mid-Atlantic states have reported the most rabies cases in rodents and lagomorphs as a result of spillover infections from the enzootic raccoon rabies virus variant circulating in this area.4,5 Among rodents and lagomorphs in the United States, groundhogs (Marmota monax) are the animals most commonly reported as rabid. This may be partially attributable to the comparatively larger body size of groundhogs than that of other rodent species. The small body size of most other rodent species likely results in higher mortality rates from injuries sustained during altercations with rabid mesocarnivores and may contribute to the rarity of smaller rodents reported as rabid. In addition, it may be more difficult to capture rodents of smaller size and submit them for diagnosis after potential exposure of humans. The purpose of the study reported here was to assess the epidemiology of rabies in rodents and lagomorphs and analyze spatial trends of rabies in groundhogs.
Mouse intracerebral LD50
Reverse transcription–nested PCR
ArcGIS Desktop, release 10, Environmental Systems Research Institute, Redlands, Calif.
3. Childs JE, Colby L, Krebs JW, et al. Surveillance and spatiotemporal associations of rabies in rodents and lagomorphs in the United States, 1985)1994. J Wildl Dis 1997; 33: 20–27.
4. Krebs JW, Strine TW, Smith JS, et al. Rabies surveillance in the United States during 1994. J Am Vet Med Assoc 1995; 207: 1562–1575.
5. Jenkins SR, Winkler WG. Descriptive epidemiology from an epizootic of raccoon rabies in the Middle Atlantic States, 1982)1983. Am J Epidemiol 1987; 126: 429–437.
7. Blanton JD, Palmer D, Rupprecht CE. Rabies surveillance in the United States during 2009. J Am Vet Med Assoc 2010; 237: 646–657.
10. Fishbein DB, Belotto AJ, Pacer RE, et al. Rabies in rodents and lagomorphs in the United States, 1971)1984: increased cases in the woodchuck (Marmota monax) in mid-Atlantic states. J Wildl Dis 1986; 22: 151–155.
13. Eidson M, Matthews SD, Wilset AL, et al. Rabies virus infection in a pet guinea pig and seven pet rabbits. J Am Vet Med Assoc 2005; 227: 932–935.