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Rabies

Updated: 10 Jan 2024, 13:59 pm IST
Medically Reviewed by

What is Rabies?

Rabies, also known as hydrophobia or Lyssa, is a viral disease that is usually transmitted by a rabid animal bite. While there’s no specific vaccine for rabies, it is preventable by vaccinating animals and keeping a safe distance from stray or unknown dogs.

Rabies is a fatal but preventable viral disease! Image courtesy: Adobe Stock

Rabies is a viral disease that affects the central nervous systems of mammals, including humans. It is primarily transmitted through the saliva of an infected animal, often through bites. Dogs account for up to 99 percent of human rabies transmissions and are a major source of rabies-related deaths. Vaccinating dogs is a key preventive measure, but if the virus is transmitted through a dog bite, it can result in severe neurological symptoms, and without treatment, it is nearly always fatal. Hence, rabies is a global health concern. You should always seek medical attention immediately if bitten by an animal with rabies potential.

Causes of Rabies

Rabies is a viral disease primarily transmitted through the saliva of infected animals, typically through bites. The rabies virus, a member of the Lyssavirus genus, affects mammals, including humans. The primary reservoirs for rabies are wild animals like bats, raccoons, skunks, and foxes. Domestic animals, such as dogs and cats, can also carry and transmit the virus.

Here’s how rabies is transmitted:

The transmission cycle usually begins when a rabid animal bites another, introducing the virus into the victim’s bloodstream. Moreover, scratches or open wounds exposed to infected saliva can also facilitate transmission.

Human cases often result from an infected animal bite, particularly in regions with high rates of rabid dogs. Scratches by infected animals and exposure to the infected saliva on the nose, eyes, mouth, and cut skin also expose the human body to the infection.

The transmission of the rabies virus between humans can occur through organ transplantation, including the cornea. Although such cases are rare, it is still possible. Hence, it is advised against using the corneas or other organs of individuals who have succumbed to rabies for transplantation.

It’s important to note that rabies is not spread through petting or coming into contact with the dried saliva, blood, urine, or feces of an infected animal.

Key Facts of Rabies

Major Symptoms
  • Fever
  • Headache
  • Weakness
  • Confusion
  • Anxiety
  • Difficult swallowing
  • Hydrophobia (fear of water)
  • Loss of appetite
  • Hallucination
  • Muscle ache
  • Disturbed behaviour
Necessary Health Tests
  • Saliva test
  • Skin biopsy
  • Cerebrospinal fluid test (CSF)
  • Blood test
  • MRI
Treatment

First aid

  • Wash the wound with soap and water
  • Press the area to release infected blood
  • Apply antibacterial ointment

Medical intervention

  • Rabies vaccine
  • Rabies immune globulin (RIG)
  • Medical observation

Symptoms of Rabies

Rabies is a viral infection that primarily affects mammals, including humans. The disease progresses in distinct stages, with symptoms intensifying over time.

Prodromal stage (1-3 days)

In the initial stage, symptoms are nonspecific and flu-like. Fever, headache, decrease in appetite, and malaise may manifest. Pain or tingling at the site of the animal bite can also occur.

Acute neurological stage (2–10 days)

As the virus advances to the central nervous system, neurological symptoms emerge. Patients may experience hyperactivity, hallucinations, and agitation. Hypersalivation and difficulty swallowing, known as dysphagia, become prominent. Additionally, individuals may exhibit hydrophobia (fear of water), difficulty swallowing, and muscle spasms.

Coma and death stage (Within days after symptoms appear)

The final stage results in paralysis, coma, and ultimately death. Respiratory failure occurs, leading to a fatal outcome. Once clinical symptoms appear, the disease is almost always fatal.

Rabies progresses rapidly, and seeking immediate medical attention after a potential exposure is crucial.

Diagnosis of Rabies

Rabies is diagnosed through a combination of clinical evaluation and laboratory tests. Initially, healthcare professionals assess symptoms such as fever, headache, discomfort at the site of the bite, and neurological changes.

Tests for rabies may include:

1. Saliva test: Your saliva may be used for a lab test to look for signs of rabies.

2. Skin biopsy: To confirm rabies, a skin biopsy from the nape of the neck is collected for analysis.

3. Cerebrospinal fluid test (CSF): In this test, the doctor will take a CSF sample from your back and send it for lab analysis. The presence of the virus or antibodies in the CSF indicates an advanced infection.

4. Blood test: Blood tests are employed to detect antibodies or viral antigens in your blood.

5. MRI: Advanced imaging techniques like MRI play a role in assessing neurological complications. MRI scans may reveal specific brain changes associated with rabies, aiding in disease staging and prognosis.

Treatment of Rabies

First aid steps for dog bite or scratch

If you or someone else is bitten by a dog, it’s crucial to take immediate first aid steps to minimise the risk of infection and complications. Begin by cleaning the wound with mild soap and water. Gently wash away dirt and bacteria, but avoid scrubbing, as it may worsen the injury. After cleaning, apply an antiseptic solution to the wound and cover it with a clean, sterile bandage.

If the skin is not broken, wash the area with warm water and soap, then apply an antiseptic solution. If the skin is broken but not bleeding, clean the area with warm water, soap, and a clean towel. Gently press the surrounding area to encourage bleeding, helping to remove germs. Clean the blood and apply an antibacterial ointment. For a bleeding wound, apply and press a clean cloth to stop bleeding, then clean the area and apply a sterile bandage. Seek immediate medical attention for a bleeding dog bite wound.

When to see a doctor for a dog bite?

While many dog bites can be managed with basic first aid, it’s essential to seek medical attention in certain situations. Consult a doctor if:

1. The bite is deep, causing significant tissue damage.
2. There is excessive bleeding that doesn’t stop with applied pressure.
3. The wound shows signs of infection, such as redness, swelling, or pus.
4. The dog that bit you appears sick or behaves strangely.
5. The bite involves the face, hands, or genitals, as these areas are more prone to complications.
6. If the animal’s rabies vaccination is not up to date.
7. You haven’t had a tetanus shot within the last five years.
8. If you are diabetic, a cancer patient, or have AIDS.

Also seek medical attention if you feel weak, disoriented, or faint and have a fever.

Medical intervention

Rabies is a potentially fatal viral infection transmitted through the saliva of infected animals, commonly through bites. Immediate and appropriate treatment is vital to prevent the onset of symptoms and the progression of the disease. Apart from providing first aid, the treatment for rabies typically involves the following steps:

Vaccination: Post-exposure prophylaxis (PEP) involves a regimen of rabies vaccines that is administered immediately after a bite in a series of shots. It is given in 4 doses on the 0, 3rd, 7th, and 14th day of the bite. It’s crucial to start this treatment as soon as possible after a potential exposure to the virus.

Rabies immune globulin (RIG): In addition to the vaccine, rabies immune globulin may be administered. This provides immediate antibodies against the virus, offering temporary protection until the body produces its antibodies.

Medical observation: After receiving the initial treatment, individuals may need to be closely monitored for any signs of rabies.

It’s important to note that once symptoms of rabies appear, the disease is almost always fatal. Therefore, seeking prompt medical attention after a potential rabies exposure is of utmost importance for effective prevention.

Rabies Related FAQs

Is rabies only a concern for mammals like dogs and bats?

No, rabies can infect any mammal, including humans. Common carriers include dogs, bats, raccoons, and skunks. It is essential to be cautious around any potentially rabid animals.

What happens if a human gets rabies?

If a human gets rabies, symptoms may include fever and headache and eventually progress to more severe neurological issues. Without prompt treatment, it may be fatal.

Is there a cure for rabies?

While there is no cure for rabies once symptoms appear, post-exposure prophylaxis (PEP) can prevent the virus from causing illness if administered shortly after exposure.

What should be done immediately in case of a dog bite?

Immediately clean the dog bite with soap and water. Seek medical attention for proper wound care and to reduce the risk of potential rabies exposure.

How to find out if you are bitten by a rabid animal or a normal animal?

To determine if an animal is rabid, observe its behavior. Rabid animals may display aggression, disorientation, excessive salivation, or unusual behavior. Report the incident to local animal control for further assessment.

How can one prevent rabies exposure?

Vaccination is the most effective preventive measure. Additionally, avoiding contact with wild or unknown animals and seeking immediate medical attention if bitten or scratched are crucial steps in preventing rabies.

Can rabies be cured once symptoms appear?

Once symptoms manifest, rabies is almost always fatal. That's why early intervention with post-exposure prophylaxis is crucial in preventing the progression of the disease after potential exposure.

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