Rabies is an infection caused by the rhabdovirus. It is typically transmitted through bite wounds from an infected animal, though cases of human infection have been reported as a result of inhaling aerosolized bat urine when visiting bat-infested caves. Common carriers of rabies include skunks, raccoons, bats and foxes.
Following a bite from an infected animal, the virus in the animal’s saliva enters the victim’s tissues, attaching to local muscles cells before penetrating local nerves and eventually progressing to the brain. There is an average of twenty to thirty days between the bite and a detectable virus in the brain.
Symptoms of rabies occur in stages. During the first one and a half days after symptoms begin, known as the prodromal stage, infected animals exhibit a change in personality, such as a once friendly animal becoming shy. A voice change may also be noticed as the larynx starts to spasm. The classic mad dog stage occurs during the next two to three days, known as the excitative stage, in which animals suffer from hallucinations and show no fear. Further, drooling and foaming of the mouth occur as the larynx becomes paralyzed and result in an inability to swallow. The next two days is known as the paralytic or dumb stage in which weakness and/or paralysis set in. Death occurs when the intercostal muscles controlling breathing become paralyzed. It is during this stage that most human exposures from animals occur.