• What are rabies symptoms in humans? The first symptoms are usually non-specific flu-like signs, such as generalized weakness, fever or headache, which may last for several days. If the exposure occurred through a bite, discomfort or numbness may occur at the site. Within days or weeks, symptoms of brain dysfunction follow, such as anxiety, confusion and agitation, which progress to delirium, abnormal behavior, hallucinations and insomnia.