7 Interesting Facts… About Rabies

What animals are prone to rabies?

The most commonly affected animals by rabies are dogs, followed by cats, horses, monkeys, livestock (such as cows and buffaloes), rodents, squirrels, and chipmunks. While the virus can be found in their saliva, such occurrences are rare.

1) Which animals are susceptible to rabies?

The most commonly affected animals by rabies are dogs, followed by cats, horses, monkeys, livestock (such as cows and buffaloes), rodents, squirrels, and chipmunks. While the virus can be found in their saliva, such occurrences are rare.

2) What is the risk of contracting rabies if bitten by an animal?

- If the biting animal is not infected with rabies, there is no risk of contracting the disease.

- If the infection status of the animal is unknown, it is advisable to assume that the animal is infected.

- Not all individuals bitten by dogs or other animals will develop the disease. On average, the chances of getting sick are around 35%, varying depending on the location of the bite.

- If bitten on the leg, the chance of getting the disease is approximately 21%.

- If bitten on the face, the chance of getting the disease is around 88%.

- Superficial or abrasion wounds carry a lower risk of disease transmission compared to multiple deep wounds.

3) How is rabies transmitted to humans?

The rabies virus is primarily present in the saliva of infected animals. The most common mode of transmission to humans is through bites. Normally, the infection cannot enter through intact skin, but it can enter through existing wounds or scratches. Additionally, the virus can enter the body through mucous membranes, including the conjunctiva, nasal mucosa, inside the mouth, anus, and genital organs, even if there are no visible wounds. Rare reports have also suggested transmission through breathing and corneal transplantation.

4) If bitten by a rabid dog, how long does it take for symptoms to appear?

The period between exposure to the rabies virus and the onset of symptoms, known as the incubation period, can vary significantly. It can range from 4 days to 4 years. Approximately 70% of patients develop the disease within 3 months after exposure. Within a year after the bite, about 96% of cases develop the disease, with symptoms typically appearing between the third week and the fourth month.

5) What are the symptoms of rabies in dogs?

Dogs infected with rabies begin to shed the virus through their saliva starting from 3 days before the onset of symptoms until 2 days after the symptoms appear.

Afterward, the virus will continuously be released through saliva until death occurs.

- The usual incubation period ranges from 3 to 8 weeks, but it can be as short as 10 days or as long as 6 months.

Symptoms of the disease can be categorized into two types:

1. Furious form: This is the most common type, characterized by aggression and restlessness.

2. Dumb form: This form does not exhibit prominent symptoms.

The symptoms of the disease progress through three stages:

1. Prodromal phase: During this initial phase, the dog's behavior undergoes changes. It may shift from being affectionate and playful to becoming lethargic. The dog eats less and drinks less water. This phase typically lasts for 2 to 3 days before entering the next stage.

2. Excitative phase: This stage involves neurological symptoms. The dog becomes agitated, restless, and may exhibit compulsive biting behaviors. It may freeze, drool excessively, have a hanging tongue, experience limb muscle weakness, lose balance, fall, and struggle to get up. These symptoms can be observed 1 to 7 days prior to the final stage.

3. Paralytic phase: This phase leads to paralysis throughout the dog's body. Once paralysis sets in, the dog will succumb to death within 24 hours, starting from the onset of symptoms. The time from onset to death does not exceed 10 days, with most cases resulting in death within 4 to 6 days. In some cases, paralysis may last 2 to 4 days, and fear of water may be observed. However, in dogs with rabies, this symptom is not typically present.

6) What are the symptoms of rabies in humans?

             The symptoms of rabies in humans can be classified into two animal-like types: furious rabies (caused by the virus multiplying in the brain), which is more common and characterized by restlessness and aggression, and paralytic rabies (caused by the virus multiplying in the spinal cord), leading to paralysis.

Symptoms in humans can be categorized into three stages.

1. Prodromal phase: This stage begins with flu-like symptoms such as fever, fatigue, and may include abdominal pain, nausea, and vomiting. Unusual symptoms may manifest, including mood changes, anxiety, restlessness, and insomnia. Itching around the bite area, or limbs on the bitten side, along with numbness and pain in the affected area, are common symptoms reported in Thai individuals.

2. Neurological symptoms stage: This stage can be further divided into various symptoms, including:

- Hydrophobia: Fear of water, accompanied by throat tightness, difficulty swallowing solid food (may choke when drinking water), and painful spasms of the throat muscles. Hydrophobia is depicted by a patient who, despite being thirsty, experiences tremors, hiccups, tense neck muscles, involuntary spitting of saliva, and drops the cup while crying out in pain, resembling a howling sound. Some patients may also experience paralysis of vocal cord muscles. Death usually occurs within 2-3 days after the onset of hydrophobia.

- Aerophobia: Fear of wind, causing the patient to startle when exposed to windy conditions.

- Nervousness: The patient becomes afraid and frightened when touched, avoids light, and prefers isolation.

- Hallucinatory mania: The patient may exhibit agitated and aggressive behavior, along with frightening hallucinations.

- Other symptoms may include paralysis.

3. Terminal stage: In this final stage, the patient becomes unconscious and enters a coma. Untreated patients typically survive no longer than 7 days after the onset of initial symptoms and no more than 3 days after the onset of neurological symptoms.

7) What should you do if scratched or bitten by a dog?

1. Immediately wash the wound with soap and water thoroughly, ensuring the depth of the wound is reached. If soap is unavailable, detergent can be used as a substitute.

2. Clean the wound repeatedly with a disinfectant like 70% alcohol.

3. If the wound is severe and bleeding, allow it to bleed for a period to flush out any saliva that may contain the virus.

4. If possible, observe the animal for symptoms (if the owner is known) and keep it under observation for at least 10 days.

5. In the event of the animal's death, it should be sent for examination to detect infection.

6. Seek immediate medical attention for rabies and tetanus vaccinations, regardless of whether symptoms can be monitored or not. This is especially crucial in cases involving stray animals or animals that bite and run away. Waiting for the animal to show symptoms is unnecessary as the incubation period in both humans and animals is uncertain and can vary widely. Humans may exhibit symptoms before animals.

7. The history of rabies vaccination for the animal or the owner's assurance that the animal has never left the house or bitten anyone may reduce the chances of the animal being infected, but it does not eliminate the risk entirely. Therefore, follow steps 1-6 as outlined above.

8. In the case of a laceration, the wound should be attended to without suturing initially due to the high risk of infection, particularly if the wound is contaminated.

By Dr. Thanet Puapornpong, Surgeon at Vibhavadi Hospital