why does rabies cause hydrophobia

Rabies causes "hydrophobia" (fear of water) mainly due to intense, painful spasms in the throat and pharynx triggered when an infected person tries to swallow liquids. This spasm makes swallowing extremely painful, so even the thought or sight of water can provoke violent throat muscle contractions, leading to a natural avoidance or "fear" of water. This symptom is not a psychological fear but a response to the excruciating pain caused by the virus affecting the nervous system and muscles involved in swallowing. Additionally, rabies increases saliva production, and the virus thrives in saliva, so the painful difficulty swallowing helps keep saliva in the mouth to aid the virus's spread. Hydrophobia is characteristic of the furious type of rabies infection, which also causes aggression and hyperactivity. In summary, hydrophobia in rabies patients is an extreme difficulty and pain in swallowing liquids caused by muscle spasms, rather than an irrational fear of water.