Signs and symptoms in animalsAnimals infected with rabies may appear sick, crazed, or vicious. This is the origin of the phrase "mad dog." However, animals infected with rabies may also appear overly friendly, docile, or confused. They may even appear completely normal.Behavior of animals with rabies may be unusual. For example, seeing a normally nocturnal wild animal during the day (for example, a bat or a fox) or seeing a normally shy wild animal that appears strange or even friendly should raise suspicion that the animal may have rabies.Signs and symptoms in humansThe average incubation period (time from infection to time of development of symptoms) in humans is 30-60 days, but it may range from less than 10 days to several years.Most people first develop symptoms of pain, tingling, or itching shooting from the bite site (or site of virus entry).Nonspecific complaints of fevers, chills, fatigue, muscle aches, and irritability may accompany these complaints. These symptoms may appear similar to those of the flu. Early on, these complaints may seem like any virus, except for the shooting sensations from the bite site.Gradually, however, the affected individual becomes extremely ill, developing a variety of symptoms, including high fever, confusion, agitation, and eventually seizures and coma.Typically, people with rabies develop irregular contractions and spasms of the breathing muscles when exposed to water (this is termed hydrophobia). They may demonstrate the same response to a puff of air directed at them (termed aerophobia). By this point, they are obviously extremely ill.Eventually, the various organs of the body are affected, and the person dies despite support with medication and a respirator.A rarer form of rabies, paralytic rabies, has been linked to vampire bat bites outside of the United States. In this form, the person who was bitten develops a paralysis, or inability to move the part of the body that was bitten. This spreads gradually throughout the body, and the person ultimately dies. Hydrophobia is less common in paralytic rabies than in classic rabies.