When symptoms do appear, it is usually 30 to 50 days following exposure. There is a direct relationship between how severe the bite is and where on the body the person bitten and how long it takes for symptoms to appear. For example, if a person's head is severely bitten, symptoms may show up in as few as 14 days. Under rare conditions, a person may not have symptoms for a year or longer after exposure to the virus. If the disease has progressed, a person will have episodes of irrational excitement which alternate with periods of alert calm.
Convulsions are common.
This reaction to water, sometimes seen as a fear of it, is typical in people with rabies and gives the disease its medical name, hydrophobia. A person usually dies from cardiac or respiratory failure within a week after the appearance of rabies symptoms, while the excited state is most prominent. If the patient survives this stage, muscle spasms and agitation stop, only to be replaced by a growing paralysis leading to death. In human rabies resulting from the bite of a rabid vampire bat, excitement and hydrophobia are usually not present and paralysis usually starts in the legs and moves upward. Once symptoms appear, the only treatment is strong support to help the person feel more comfortable.