Rabies is a disease caused by a virus that is spread through a bite or scratch caused by an animal. When rabies symptoms appear, it is too late to save the patient. Therefore, knowing the incubation period of rabies is extremely important. Thanks to that, we can promptly vaccinate before symptoms appear and lead to death.

Incubation Period of Rabies

In humans, the incubation period of rabies (the time between initial exposure to the virus and onset of disease) typically ranges from 2 to 8 weeks. In rare cases, it can vary from 10 days to 2 years. This is the time before symptoms appear.

The incubation period of rabies is shorter for children and in people exposed to large amounts of the rabies virus. The viral load depends on the size, severity, and location of the animal’s bite or scratch. The closer the bite is to the brain, the sooner rabies symptoms are likely to appear.

In animals, the incubation period for rabies depends on the species of animal. For dogs, it usually ranges from 14-60 days.

The Stages of Development of Rabies

Proto-Million stage (early stage)

At this stage, the person will develop flu-like symptoms, including:

• Fever 38oC or higher
• Headache
• Nervousness
• Tired
• Sore throat and cough
• Nausea and vomiting
• Discomfort at the site of the bite

These symptoms last 2 to 10 days and worsen over time.

Acute neurological phase

Neurological symptoms during this stage include:

• Confusion and aggression
• Paralysis, muscle twitching, and neck stiffness
• Shortness of breath and difficulty breathing
• Allergies or excessive salivation, possibly foaming at the mouth
• Fear of water or hydrophobicity, difficulty swallowing
• Hallucinations, insomnia
• Permanent erection in men
• Fear of light
• Towards the end of this stage, breathing becomes rapid and inconsistent.
• Coma and death

If the patient falls into a coma, death will occur within hours, longer if they are fitted with a ventilator. Rarely, the patient can recover when the disease is already in this late stage.

Why does rabies make sick people afraid of water?

Rabies in humans is often referred to as “hydrophobicity” because it causes a fear of water in patients.

When infected, the person will feel a violent constriction in the throat when trying to swallow. Even the thought of swallowing water can cause spasms and discomfort. This is the main cause of the patient’s fear of water. If the infected animal can swallow saliva easily, it will reduce the risk of spreading the virus to a new host.

Factors Affecting the Development of Rabies

Factors that influence the development of rabies infection are:

• Contact type
• Severity of the bite
• Amount of rabies virus entering the body
• Kind of animal bite
• Patient’s immune status
• Bitten area

Wounds to the head and neck, as well as those in nerve-ending areas such as fingers, typically have a shorter incubation period of rabies due to the shorter distance the virus enters and the nerve tissue.

The incubation period of rabies usually lasts from a few days to several months, while the time from onset of illness to death ranges from 1 to 7 days.

Learn more about Infectious Diseases in Children here.