Why Does Rabies Cause Hydrophobia?

Rabies is a viral disease that can affect the central nervous system and can be transmitted to humans through the bite or saliva of an infected animal. Hydrophobia, or fear of water, is a well-known symptom of rabies, and it is often associated with the disease. However, it’s important to clarify that hydrophobia in the context of rabies is not a psychological fear of water but rather a physical manifestation of the disease. Here’s why it occurs:

  • Difficulty Swallowing: One of the hallmarks of rabies infection is the involvement of the nervous system, particularly the cranial nerves. As the virus progresses, it can affect the cranial nerves responsible for swallowing, making it extremely painful and difficult for the infected person to swallow. Even the thought of swallowing liquids, including water, can trigger intense spasms of the throat muscles.
  • Throat Muscle Spasms: The pain and discomfort associated with attempting to swallow liquids can lead to severe muscle spasms in the throat and larynx (voice box). These spasms can be triggered by the sight, sound, or even the thought of water, which is why it’s often described as hydrophobia. The spasms can be extremely painful and distressing.
  • Saliva Production: As the virus progresses, it also affects the salivary glands, leading to excessive production of saliva. The combination of difficulty swallowing and excessive saliva production can result in the characteristic foaming at the mouth seen in some rabies cases.

Hydrophobia is a classic symptom of rabies, but it is not present in all cases, and the progression of symptoms can vary. Other neurological and behavioral changes, such as agitation, confusion, hallucinations, and paralysis, are also common in advanced stages of rabies infection.

It’s important to note that rabies is a deadly disease, and once symptoms appear, it is almost always fatal if left untreated. Therefore, if someone is bitten by an animal suspected of carrying rabies, it is crucial to seek immediate medical attention. Post-exposure prophylaxis (PEP), which involves a series of rabies vaccinations, can be administered after a potential exposure to prevent the onset of symptoms and the progression of the disease. Once symptoms of rabies appear, there is no effective treatment, and the disease is virtually always fatal.