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General Information About Rabies


Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The vast majority of rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats, and foxes. Domestic animals account for less than 10% of the reported rabies cases, with cats, cattle, and dogs most often reported rabid. 


In Colorado, the primary reservoirs for rabies are bats and skunks. Starting in 2008, rabies in skunks began to spread of eastern Colorado towards the Front Range (see skunk monitoring protocol). Instances of rabies among other wild and domestic animals are rare. A few cases have recently been documented in foxes in Colorado, due to infection with rabies from skunks. Rodents and lagomorphs (hamsters, guinea pigs, squirrels, rabbits, and hares) have never been positive for rabies in Colorado, with the exception of one muskrat (large wild rodent related to beavers) in Morgan County in 2010, in the middle of a skunk rabies epizootic (outbreak among animals). Rodents and lagomorphs are rarely positive anywhere in the country. The last reported cases of rabies occurred in Colorado in the following domestic animals: dog (2003 - imported from Texas), cat (2010 & 2008). The last case of dog rabies acquired in Colorado occurred in 1974. The last reported case of rabies in a human occurred in 1931.


Rabies virus infects the central nervous system, causing encephalopathy and ultimately death. Symptoms of rabies in humans are initially nonspecific, consisting of fever, headache, and general malaise. As the disease progresses, neurological symptoms appear and may include insomnia, anxiety, confusion, slight or partial paralysis, excitation, hallucinations, agitation, hypersalivation, difficulty swallowing, and hydrophobia (fear of water). Death usually occurs within days of the onset of symptoms.


There is no treatment for rabies after symptoms of the disease appear. However, an extremely effective rabies vaccine can provide immunity to rabies when administered after an exposure (postexposure prophylaxis) or for protection before an exposure occurs (preexposure prophylaxis). 


If you are bitten by an animal, please contact your medical provider or local health department to determine the potential for rabies exposure, the need for treatment, and to decide whether or not to test the animal for rabies.