Rabies is a disease primarily of animals. Airborne spread has been demonstrated in a cave where a myriad of bats were roosting, and in laboratory settings, but this occurs very rarely.
Animals can be infectious for several days before exhibiting signs of the disease.
In humans, onset of disease is characterized by apprehension, headache, low-grade fever, malaise and vague sensory changes. Discomfort and irritation may be experienced in the area of the animal bite. Delirium and convulsions usually precede death from respiratory failure. Without medical intervention, the normal duration is 2 to 6 days, sometimes longer. This variability depends on the severity of the wound inflicted by the rabid animal, the site of the wound in relation to the richness of the nerve supply and its distance from the brain, the amount and strain of virus introduced, the protection provided by clothing, and other factors.