Rabies: Symptoms, Transmission, and What to Do After an Animal Bite or Scratch

Rabies is a viral infection transmitted from animals to humans that affects the central nervous system. Despite its common association with dogs, rabies is not transmitted by dogs alone. Other mammals, including cats and certain wild animals, can also become infected and transmit the virus.

One of the most important facts about rabies is that once clinical symptoms appear, the disease is almost always fatal. However, rabies can be prevented if a person at risk receives appropriate and timely care after exposure.

Therefore, if you are bitten or scratched by an animal, or if animal saliva comes into contact with a wound or mucous membrane, you should not wait for symptoms to develop. Wash the affected area immediately and seek medical attention for a proper risk assessment.

What Is Rabies?

Rabies is caused by the rabies virus, which can enter the body through wounds or mucous membranes. After entering the body, the virus can travel along the nerves toward the central nervous system and brain, causing severe inflammation and neurological dysfunction.

Transmission most commonly occurs through the saliva of an infected animal, particularly through bites. However, scratches that break the skin or exposure of wounds, eyes, mouth, or nose to infected saliva may also transmit the virus.

Touching or feeding an animal, as well as being licked on intact skin, is generally not considered an exposure requiring rabies vaccination. However, if you are unsure whether the skin was intact, it is advisable to have the exposure assessed by a healthcare professional.

Why Is Rabies So Dangerous?

The major concern with rabies is that treatment should not be delayed until symptoms develop. Once the virus reaches the central nervous system and clinical symptoms begin, the disease is almost invariably fatal.

In contrast, post-exposure prophylaxis (PEP) can effectively prevent the virus from reaching the nervous system when administered appropriately before symptoms appear. Post-exposure prophylaxis may include:

• Thorough washing and cleaning of the wound
• Rabies vaccination
• Administration of rabies immunoglobulin when indicated

A healthcare professional will determine the appropriate treatment based on the type of exposure, location and severity of the wound, previous rabies vaccination history, and other individual factors.

How Is Rabies Transmitted?

The risk of rabies occurs when saliva from an infected animal enters the body. Situations that should be medically assessed include:

• Being bitten by a dog, cat, or other mammal and having the skin broken
• Being scratched and developing an abrasion or open wound
• Animal saliva coming into contact with broken or damaged skin
• Animal saliva entering the eyes, mouth, nose, or other mucous membranes
• Direct contact with a bat in circumstances where a bite or scratch cannot be ruled out

The risk should not be assessed solely based on the size of the wound. Even a small wound may require post-exposure prophylaxis.

Rabies Incubation Period

After exposure to the virus, symptoms may not appear immediately. The period between exposure and the onset of symptoms is known as the incubation period.

The incubation period generally ranges from several weeks to several months, although it can vary considerably from person to person. Factors that may influence the incubation period include:

• Location of the wound
• Severity of exposure
• Amount of virus introduced
• Age of the exposed person
• Previous rabies vaccination history

Therefore, even if an animal bite occurred several days ago or the wound has already begun to heal, this does not mean it is safe to wait for symptoms. If you have not yet received a medical assessment after a possible rabies exposure, seek medical attention as soon as possible.

Symptoms of Rabies

In the early stages, symptoms may be nonspecific and resemble those of other infections. They may include:

• Fever
• Headache
• Fatigue or general discomfort
• Pain, burning, itching, or unusual sensations around the previous bite or scratch site

As the disease progresses and affects the brain, symptoms may include:

• Agitation
• Confusion
• Changes in behavior
• Difficulty swallowing
• Fear of water or abnormal reactions when attempting to drink
• Increased sensitivity to air movement
• Hallucinations
• Seizures
• Muscle weakness or paralysis
• Loss of consciousness

Not everyone with rabies develops obvious aggression or fear of water. Some people may instead develop progressive weakness and paralysis.

What Should You Do After a Dog or Cat Bite?

If you are bitten or scratched by an animal, or if animal saliva comes into contact with an open wound, take action immediately. Do not wait for the animal to develop symptoms or for yourself to become ill.

1. Wash the Wound Immediately: Wash the affected area thoroughly with soap and running water for at least 15 minutes. Proper wound washing is an important first step because it helps reduce the amount of virus that may be present around the wound.
2. Apply an Antiseptic if Available: After washing the wound, an appropriate antiseptic, such as povidone-iodine, may be applied. Do not use herbs, powders, or irritating substances as substitutes for proper medical care.
3. Seek Medical Attention Promptly: A healthcare professional will assess whether rabies vaccination is necessary. In high-risk exposures, rabies immunoglobulin may also be recommended. Healthcare professionals may also assess the need for tetanus prevention, treatment of bacterial infection, and additional wound care.
4. Complete the Vaccination Schedule: If rabies vaccination is recommended, follow the vaccination schedule and complete all required doses. Do not stop or change the schedule on your own. People who have previously received rabies vaccination may require a different post-exposure regimen from those who have never been vaccinated. Always inform your healthcare provider about your previous rabies vaccination history.

Should You Wait and Observe the Dog or Cat First?

You should not wait for an animal to develop symptoms before seeking medical attention, particularly in areas where rabies continues to occur.

If the animal is a dog or cat that can be safely confined and observed, it may be monitored for 10 days according to the advice of relevant health or veterinary authorities. However, observing the animal should not be used as a reason to delay medical assessment or post-exposure prophylaxis when it is indicated.

If the animal becomes ill or dies during the observation period, notify veterinary or public health authorities so that appropriate rabies testing can be considered. Avoid handling the animal’s body with bare hands.

When Should You Seek Urgent Medical Attention?

After a possible rabies exposure, you do not need to wait for symptoms to appear before going to a hospital. Medical assessment should be sought promptly following exposure. Particular attention is needed if:

• You were bitten or scratched and the skin was broken or bleeding
• You have multiple or severe wounds
• You were bitten on the face, head, neck, or hands
• Animal saliva entered your eyes, mouth, or nose, or came into contact with an open wound
• The animal showed unusual behavior
• The animal died or disappeared after the incident
• The animal’s vaccination history is unknown
• The exposed person is a young child
• You have a weakened immune system or are taking immunosuppressive medication

If you develop fever together with neurological symptoms such as confusion, agitation, difficulty swallowing, fear of water, seizures, or weakness after a history of animal exposure, seek emergency medical care immediately and inform healthcare professionals about the previous animal bite or scratch.

How Do Healthcare Professionals Assess Rabies Risk?

Following an animal bite or scratch, the assessment is not based solely on the appearance of the wound. Healthcare professionals may consider several factors, including:

• The type of animal involved
• The nature of the exposure
• The location and severity of the wound
• Whether the animal showed abnormal behavior
• Whether the animal can be safely confined and observed
• The animal’s vaccination history
• The exposed person’s previous rabies vaccination history
• The person’s overall health and immune status

Based on this assessment, healthcare professionals will determine whether rabies vaccination, rabies immunoglobulin, or other treatment is required.

How Can Rabies Be Prevented?

Rabies prevention is not limited to receiving vaccination after an animal bite. Reducing the risk of exposure in the first place is equally important.

• Vaccinate Your Pets: Dog and cat owners should ensure that their pets receive rabies vaccination according to the recommendations of veterinarians and relevant authorities.
• Avoid Contact With Unfamiliar Animals: Avoid approaching, touching, or playing with unfamiliar dogs, cats, or wild animals, especially animals displaying unusual behavior.
• Teach Children How to Interact Safely With Animals: Children may be more likely to interact with animals and may not always tell an adult when they have been bitten or scratched. Teach children not to tease animals, disturb them while they are eating, or approach unfamiliar animals.
• People at Higher Risk Should Discuss Pre-Exposure Vaccination: People whose occupations or activities regularly place them at risk of rabies exposure, such as certain professionals who work with animals or the rabies virus, may be advised to receive pre-exposure prophylaxis (PrEP). However, receiving rabies vaccination before exposure does not mean that medical attention is unnecessary after a possible rabies exposure.

Who Should Consult a Healthcare Professional?

You should seek medical assessment if:

• You were bitten or scratched by a mammal and the skin was broken
• An animal licked an open wound or abrasion
• Animal saliva came into contact with your eyes, mouth, or nose
• You are unsure whether a previous animal exposure placed you at risk of rabies
• You have previously received rabies vaccination but are unsure whether booster doses are required
• You did not complete your post-exposure vaccination schedule or missed a scheduled dose
• You have a weakened immune system or are taking immunosuppressive medications
• You are caring for a young child, are pregnant, or have an underlying medical condition and have experienced a potential rabies exposure

Do not stop vaccination or alter the vaccination schedule without medical advice. The appropriate management should be determined by a healthcare professional based on the circumstances of each exposure.

Summary

Rabies is a severe viral infection that affects the nervous system. Once clinical symptoms develop, the disease is almost always fatal. However, rabies is preventable when appropriate post-exposure care is provided promptly.

If you are bitten or scratched by a dog, cat, or other mammal, or if animal saliva comes into contact with a wound or mucous membrane, wash the affected area thoroughly with soap and running water for at least 15 minutes and seek medical attention as soon as possible.

A healthcare professional can determine whether rabies vaccination and rabies immunoglobulin are required.

The key message is simple: do not wait for symptoms to appear. The most effective time to prevent rabies is after exposure and before the disease develops.

Prepared by: Pharmacist Punyanuch Angkanawin

References

1. World Health Organization (WHO). Rabies
2. Centers for Disease Control and Prevention (CDC). About Rabies
3. Department of Disease Control, Ministry of Public Health, Thailand.Rabies.