Why Does Rabies Cause Hydrophobia?

If you’re a pet owner, you know that rabies is a dangerous and often fatal disease. You may already know that one of its symptoms is hydrophobia, an extreme fear of water, but do you know why that occurs? Read on to learn more about rabies and the science behind its symptoms. 

What Is Rabies?

Rabies is a viral infection caused by lyssaviruses that can affect warm-blooded animals such as bats, dogs, and humans. The virus attacks the central nervous system 30-50 days after entering a victim’s body. In rare cases, the infection may stay hidden for years.

As the virus takes root in the body, it causes inflammation in the brain and tissues surrounding the spinal cord, leading to seizures and partial paralysis. Victims also exhibit aggressive or abnormal behavior and a fear of water. Once the symptoms manifest, fatality is almost inevitable.

There are two main types of rabies: furious and paralytic rabies. Furious rabies is the most common type, accounting for over 80% of cases. It’s the type that comes to mind when rabies is the focus of any discussion. Victims with furious rabies will display aggressive or erratic behavior, frothing at the mouth, and increased saliva production.

Paralytic rabies causes slow paralysis, which begins with muscle weakness and a loss of sensation around the bite area.

Overall, rabies deaths are very rare for humans in the United States, thanks to mandatory vaccines for pets. The mortality rates are highest in regions without strict quarantine and animal vaccination programs.

Why Does Rabies Cause Fear of Water?

Rabies affects parts of the brain that controls speaking, swallowing, and breathing. It alters the saliva production process and causes painful muscle spasms that discourage swallowing. 

The virus thrives in saliva. Swallowing reduces the spread. Therefore, it immediately acts to make its victim produce more saliva and spread that saliva on its surroundings rather than swallowing it. So, “why are animals infected with rabies afraid of water?” Really, they’re afraid of any food or drink.

Thus, rabies causes hydrophobia, but only indirectly. It causes the fear of swallowing anything, including water—a condition known as dysphagia. This explains why infected animals tend to drool excessively as the disease progresses, rabies attempting to spread itself.

Does Rabies Cause Hydrophobia in Dogs?

A dog can develop hydrophobia following a rabies infection. However, it’s rare. Hydrophobia is a sign of rabies that is more often reported in humans than in dogs or cats.

If your dog gets in an altercation that may have exposed them to rabies, call your vet for guidance immediately. If you wait long enough that symptoms of rabies become present, the disease will have spread beyond medical remedies. Once neurological symptoms like excessive drooling appear, the dog will not recover.

Remember that rabies symptoms may not appear until weeks after the suspected exposure. So, checking if your dog drinks water a few days after the suspected exposure isn’t a foolproof method of ruling out rabies.

Is Hydrophobia Caused by Dog Bites?

A dog bite doesn’t cause hydrophobia on its own. Only bites from rabid dogs can cause hydrophobia. However, getting professional evaluation and treatment after a dog bite is essential. Other health problems that may arise due to neglected dog bites include:

Bacterial Infection

Some of the bacteria in a dog’s mouth include staphylococcus, capnocytophaga, and pasteurella. Some dogs may also carry Methicillin-resistant Staphylococcus aureus (MRSA).  

Some of these germs will cause bacterial infections if a dog bites through the skin. The risk of infection is higher in immunosuppressed individuals.

Nervous and Musculoskeletal Damage

A dog bite can damage blood vessels, muscles, and nerves—regardless of the bite size. Similarly, a bite from a large dog breed can cause fractured, broken, or splintered bones in the hands, feet, and legs. Therefore, it’s best to seek emergency treatment immediately after a bite.

Tetanus Infection

Tetanus is an uncommon infection in the United States because children are vaccinated against it. Adults also get booster shots every ten years. However, a dog bite can cause tetanus infection in people with weak immune systems or who have lived without booster shots for more than 20 years.

Get Help and Protection Against Rabies 

We hope our post on rabies and hydrophobia has answered any questions you may have about rabies symptoms. Rabies is a dangerous and often fatal disease, but it can be treated if caught early. If you think your pet may have had contact with a rabid animal, please call the Penny Paws location nearest you. Our team of experts is here to help your pet get the care that it needs.