What are the signs and symptoms of rabies?
After a rabies exposure, the rabies virus has to travel to the brain before it can cause symptoms. This time between exposure and appearance of symptoms is the incubation period. It may last for weeks to months. The incubation period may vary based on
- the location of the exposure site (how far away it is from the brain),
- the type of rabies virus, and
- any existing immunity.
The first symptoms of rabies may be similar to the flu, including weakness or discomfort, fever, or headache. There also may be discomfort, prickling, or an itching sensation at the site of the bite. These symptoms may last for days.
Symptoms then progress to cerebral dysfunction, anxiety, confusion, and agitation. As the disease progresses, the person may experience delirium, abnormal behavior, hallucinations, hydrophobia (fear of water), and insomnia. The acute period of disease typically ends after 2 to 10 days. Once clinical signs of rabies appear, the disease is nearly always fatal, and treatment is typically supportive. Less than 20 cases of human survival from clinical rabies have been documented. Only a few survivors had no history of pre- or postexposure prophylaxis.
The signs, symptoms, and outcome of rabies in animals can vary. Symptoms in animals are often similar to those in humans, including early nonspecific symptoms, acute neurologic symptoms, and ultimately death.