Rabies

Symptoms of rabies can be divided into the following stages:

Stage 1 (Incubation): This is the period from exposure to the virus until the onset of symptoms, varying from person to person. This duration is generally 2 to 3 months but may range from 1 week to 1 year, depending on factors such as the site of entry of the virus and the viral load.

Stage 2 (Prodrome): This stage consists of non-specific symptoms that mostly resemble the flu, along with several gastrointestinal symptoms:

• Fever
• Headache
• Malaise
• Decrease in appetite
• Pain, numbness, tingling, and itching at the wound site

Stage 3 (Neurological): In this stage, the virus reaches the central nervous system, causing fatal inflammation of the brain and spinal cord, which can manifest as the following symptoms:

• Anxiety
• Confusion
• Agitation
• Delirium
• Disturbed behavior
• Hallucinations
• Hydrophobia (fear of water)
• Insomnia
• Muscle aches
• Weak arms and legs
• Difficulty in swallowing
• Aerophobia (fear of fresh air)

Stage 4 (Coma): This stage usually develops within ten days of stage 3. Patients may experience persistent hydrophobia and can develop paralysis.

Stage 5 (Death): Stage 4 can lead to death within 2 to 3 days without supportive care.

Rabies is caused by the rabies virus that is typically transmitted from infected animals. The virus resides in the saliva, brain, and spinal cord of the infected animal. Rabies can infect mammals such as:

• Dogs
• Cats
• Bats
• Monkeys
• Foxes
• Raccoons
• Skunks
• Jackals
• Mongooses

The most common source of transmission to humans is dogs.

Transmission

The salivary glands play a crucial role in spreading the infection. When an infected animal bites, the virus is released through saliva into the person's body. The infection can spread through:

• Bite of an infected animal
• Scratches from the claws of an infected animal
• Exposure to infected saliva through the nose, eyes, mouth, or broken skin

Rabies virus can also be transmitted from human to human through the transplantation of the cornea or other organs. Although this transmission is rare, it is possible. Therefore, the corneas and other organs of a person who died of rabies should not be used for transplantation.

Note: Rabies is not spread by petting or touching dried saliva, blood, urine, or feces of a rabid animal.

After entering the bloodstream, the virus infiltrates the central nervous system. Once the infection is established in the brain, the virus travels down the nerves and multiplies in different organs, causing various complications.

• Low knowledge levels regarding rabies: Rabies is highly prevalent in areas where people have limited knowledge about rabies and dog bites. Cases are especially common in rural areas where individuals are unaware of the measures necessary to prevent and manage rabies.
• Exposure to unvaccinated dogs: Dogs are the primary source of rabies transmission. Contact with stray or unvaccinated dogs can lead to infection.
• Living in rabies-endemic countries: Individuals residing in countries where rabies is endemic and where there is poor control over dog and wildlife populations are at a higher risk of rabies infection.
• Age: Children are at a greater risk of contracting the virus, as they are more likely to be attacked by animals. Most rabies cases occur in children who are bitten by dogs, particularly on their arms and faces.

An immediate medical attention is essential if an individual is suspected to have been bitten or scratched by an animal, as there is no direct way to recognize a rabid animal. While diagnostic tests can confirm the infection, they usually take time, and reliance on the results can delay the treatment process.

Testing the Animal

The animal that is caught biting or scratching is first tested for rabies. This testing may save a patient from unnecessary physical, psychological, and financial stress if the animal is not found to be rabid. Rabies is usually diagnosed by the direct fluorescent antibody (DFA) test, which detects rabies virus antigens in the brain tissue of the euthanized (humanely put to death) animal. Healthy animals, such as vaccinated dogs or cats, are typically not tested and are kept under observation for 10 days. After this period, a doctor usually decides on further action after consulting with the local health department.

Testing in Humans

Rabies can be confirmed by various tests that detect the whole virus, viral antigens, or nucleic acids in infected tissues. Some of the tests include:

• Lumbar Puncture: A sample of cerebrospinal fluid is taken to detect the virus using a thin needle from the lower part of the lumbar spine.
• Nuchal Skin Biopsy: This is the most reliable method of detecting the rabies virus during the first week. A sample is collected from the skin at the back of the neck, and the virus is detected using immunofluorescent antibody staining under a microscope.
• Real-Time Polymerase Chain Reaction (RT-PCR): This test analyzes saliva for the presence of the rabies virus. It amplifies the genetic material (RNA) of the virus for easier identification and is used as a confirmatory test due to its high sensitivity.
• Blood Tests: These tests are not commonly used for detecting the rabies virus, as virus-specific antibodies take time to appear in the blood. They are mainly used to assess the efficacy of rabies vaccines given to the patient. The most common antibody tests are:
  • Fluorescent Antibody Virus Neutralization (FAVN) Test
  • Rapid Fluorescent Focus Inhibition (RFFIT) Test

Imaging Tests

These tests are usually performed to diagnose rabies encephalitis. They include:

• Magnetic Resonance Imaging (MRI) of the Head: This imaging technique uses magnetic fields and radio waves to create detailed pictures of the brain.
• Computed Tomography (CT) Scan of the Head: This method employs X-rays to produce detailed images of the head.

Eliminating rabies in animals

Rabies is a vaccine-preventable disease. It is important to keep the vaccinations of your dogs, cats, ferrets, and selected livestock up-to-date. A booster vaccination is also recommended in case your dog or cat is attacked or bitten by a wild animal.

Vaccination

The same vaccine that is used in animals is also used to immunize people after an exposure. In some cases, vaccination is also required in humans before exposure to rabies. The vaccines for rabies have been available for more than 125 years. Earlier nerve tissue vaccines have now been replaced with various modern cell culture and embryonated egg-based vaccines (CCEEVs). CCEEVs are more effective than earlier vaccines and have fewer side effects.

Vaccinations of high risk people (Pre-exposure vaccination)

Vaccination is also recommended for people who are at high risk of contracting the disease. These include:

• Veterinarians or animal handlers
• Veterinary students
• People who study or explore animals
• Students working on the rabies virus
• People traveling to rabies-endemic countries

Vaccination is also recommended for children and infants living in areas with a high incidence of rabies, where the supply of immunoglobulin is limited. The vaccine can be administered via the intramuscular route or intradermally on days 0, 7, and 21 or 28. Booster doses are required only in cases of continuous exposure to the rabies virus. In the event of exposure to the rabies virus, vaccinated individuals still require post-exposure prophylaxis.

Vaccination after an animal bite

Vaccination is required if a person is bitten by a rabid animal. In this case, a doctor will determine if you need the rabies vaccine. The vaccine is given in 4 doses if you have not previously been vaccinated for rabies. The first dose is administered immediately after the bite, followed by three additional doses given after 3 days, 1 week, and 2 weeks after the first dose. Individuals who have already received the rabies vaccine require only 2 doses: the first dose immediately after the bite and the second dose after 3 days.

Vaccines can lower immunity for a period of time, so it is essential to inform your doctor if you:

• Had an allergic reaction to the rabies vaccine in the past
• Have severe other allergies
• Have HIV infection
• Have cancer
• Are on medications that can affect your immune system
• Are pregnant or breastfeeding

If it is confirmed that you have been bitten by a rabid animal, you need to get vaccinated even in the presence of these conditions.

Side effects of vaccination

The side effects of rabies vaccines are generally mild and usually resolve on their own. Common side effects include:

• Pain, swelling, and redness at the injection site
• Headache
• Upset stomach
• Pain in the stomach
• Muscle aches
• Dizziness

Some rare side effects may include:

• Itchy spots on the skin
• Joint pain
• Fever

Avoiding animal exposure

The best protection against rabies is to avoid contact with wild animals that can transmit the virus. The following measures should be taken to avoid exposure:

• Do not touch injured animals. If you find an injured animal, contact local authorities immediately for assistance.
• Do not feed, play with, or pet unknown animals, especially in areas where rabies is known to occur.
• Do not touch stray dogs and cats while traveling.
• Do not allow your pets to roam freely, as they may be infected by other animals.
• Do not leave garbage or pet food outside, as it may attract wild or stray animals.
• Do not keep wild animals as pets.
• Do not ignore unusual behavior in your pet. Any change in behavior should be reported to a veterinarian immediately.
• Do not allow children to touch or feed stray cats and dogs. Educate and remind children to stay away from stray animals.

Awareness on rabies

It is crucial to understand the risk of rabies. Rabies is a fatal disease transmitted through animals, particularly dogs. However, rabies in humans can be prevented through prompt vaccination and appropriate medical care. If you are bitten or scratched by an animal, inform your doctor immediately. Educating both children and adults about rabies and its prevention plays a vital role in limiting exposure. Increasing awareness of rabies prevention and control in communities includes education on responsible pet ownership, how to prevent dog bites, and immediate care measures after a bite.

What to do after a bite or scratch by an animal, particularly a dog?

• Wash the wounds with soap and water immediately, as this will reduce the chances of infection.
• Flush the wound thoroughly for about 15 minutes with water.
• Administer first aid to the wound, including applying an iodine-containing or antiviral medication.
• Capture the animal in a large box, or at least identify it, if possible. Do not risk further injury to yourself.
• Call your family doctor immediately and explain the situation regarding the bite.
• Contact the Department of Health and the animal control officer, providing them with an accurate description of the animal.
• Avoid covering the wound with dressings or bandages.
• Keep the biting animal under observation for 10 days.

What to do if your pet is bitten or scratched by another animal, particularly a dog?

• Wear rubber gloves while washing your pet’s wounds.
• Call your pet’s veterinarian immediately.

Post-exposure prophylaxis (PEP)

There is no specific treatment for rabies once symptoms begin to develop. Therefore, the focus is on preventing exposure. Even if rabies is not confirmed, treatment should start immediately. This is called post-exposure prophylaxis (PEP) and is intended to prevent infection. PEP refers to the prompt treatment of a bite that might expose a person to rabies, helping to prevent the entry of viruses into the brain. It consists of:

• Extensive wound washing: This includes immediate washing of the wound with water, soap, detergent, and povidone iodine for at least 15 minutes, which may help in removing or killing the virus.
• Administration of rabies immune globulin: This provides immediate protection before the vaccine begins to take effect.
• Administration of rabies vaccine: The vaccine is injected immediately after a bite, given in 4 doses on the 0th, 3rd, 7th, and 14th days post-bite. An additional dose on day 28 is also administered to patients with a weakened immune system.

Rabies is a serious disease that involves the nervous system. Most patients are admitted to hospitals for treatment. Caregivers and family members play a crucial role in maintaining the overall health of the patient. The following measures can be taken by those caring for the individual:

• Keep the patient calm, comfortable, and free from emotional upset.
• Avoid contamination from saliva and broken skin of the patient by taking special precautions.
• Keep the patient in a quiet room.
• Keep the patient away from triggers (loud noise, intense light, and cold air) that may cause muscle spasms and convulsions.
• Allow the patient to get proper sleep to control excitability.
• Keep the patient hydrated.

The rabies virus travels through the peripheral nervous system and targets the central nervous system (brain), which can lead to neurological complications such as encephalomyelitis. This may also result in anxiety, agitation, and delirium. The virus can travel back to the peripheral nervous system and attack various organs, including the salivary glands. It can cause complete failure of the entire nervous system, potentially resulting in the death of the infected individual. These changes can lead to several complications in patients.

• Seizures
• Fasciculations
• Psychosis
• Aphasia
• Autonomic instability
• Paralysis
• Coma
• Cardiopulmonary disorders
• Multiple organ failure
• Cardiac arrest
• Hypotension
• Confusion
• Paralysis of lower legs
• Problems swallowing due to painful throat and voice box spasms
• Insomnia
• Apnea
• Death