Rabies

What is Rabies?

Rabies is a disease that leads to a condition called viral encephalitis, that affects the brain causing up to 70,000 deaths each year worldwide. It generally spreads to humans through the saliva of infected animals. Rabies is one of the oldest recognized diseases, with instances reported as far back as 4,000 years ago. Traditionally, a bite from a rabid animal was almost always deadly. It was so feared in the past that some people, after being bitten by a potentially rabid animal, would even take their own lives.

In 1885, Pasteur introduced a vaccine for rabies, which has led to highly effective preventative measures in developed countries. For instance, in the United States, there have been only about two deaths per year from rabies for the last two decades. However, not all countries have had the same success and the disease remains a significant problem in less developed areas.

What Causes Rabies?

The Rhabdoviridae family includes a type of virus that’s shaped like a bullet and is responsible for causing rabies. This virus is made up of two main parts. The first part is the structural section, known as the viral envelope, and the second part is the functional area that carries the core of the virus, known as the ribonucleocapsid core.

This virus generally spreads when an infected mammal bites another creature. Both domestic animals like pets and wild animals can transmit the virus. However, it can also be passed on if the saliva of an infected animal comes into contact with broken skin or mucous membranes, which are the soft, wet areas inside the body like your nose or mouth.

There are other less common ways this virus can spread. For example, someone might inhale it if it has been aerosolized, which means made into tiny particles that can hang in the air. It can also be ingested, passed from a mother to a baby during pregnancy, or transferred during an organ transplant.

Risk Factors and Frequency for Rabies

Rabies causes between 30,000 to 70,000 deaths globally each year, mostly in less developed countries. On the other hand, in the United States, very few cases of rabies in humans are reported. This might be due to the widespread use of treatment after exposure and existing prevention programs. In developed countries, pets are only responsible for about 10% of rabies cases. The majority of cases are caused by wild animals like skunks, raccoons, foxes, and bats. However, any mammal can carry rabies. Though small rodents and the rabbit family are generally considered safe, as they aren’t expected to survive a bite from a rabid animal, there have been a few incidents where rats have transmitted rabies. Given that the types of animals that carry rabies can vary by region, it’s important to know which animals in your area could potentially carry rabies. This information can help determine who might need treatment after exposure.

Signs and Symptoms of Rabies

If a person gets bitten by an animal with rabies, the symptoms might not appear right away and can take days or even years. The disease progresses in five stages:

Incubation: This is the period from when a person is bitten to when the first symptoms appear.
Prodrome: The symptoms during this phase are similar to the flu, such as body aches, fever, and stomach problems.
Acute neurologic illness: At this stage, there are three types of neurological symptoms one could experience. This can include:

Encephalitic (“furious”) includes symptoms like fear of water or air, mental changes, agitation, and increased reflexes. This is the most common form, occurring in 85% of cases. Patients with this form also experience rapid heartbeat, rapid breathing, neck stiffness, and a positive Babinski’s sign (a reflex test of the foot).
Paralytic (“dumb”) is less common and does not typically include the agitation or fear of water seen in the first form. Rather, it is characterized by weakness, mental changes, ongoing fevers, and bladder dysfunction. This form is often confused with Guillain-Barre syndrome (a neurological disorder).
A rare non-classic form is typically associated with seizures and severe motor and sensory symptoms.

Coma: In this stage, the person often slips into a coma. This usually happens 10 days after the third phase. Symptoms at this stage may include intense fear of water, periods of not breathing, and muscle weakness.
Death: After the onset of the coma stage, death usually occurs within 2 to 3 days due to heart and lung failure – even with the best supportive care. Rabies is almost always fatal.

Recognizing these symptoms as early as possible is important as rabies is almost always fatal once symptoms appear.

Testing for Rabies

Rabies is a disease that can be quite tricky to detect, especially if there’s no clear evidence of a person being bitten by a rabid animal. In the early stages, it often resembles other illnesses like the flu or common viral infections, and in later stages, it can seem similar to tetanus, botulism, or other conditions like Guillain Barre syndrome.

Doctors often conduct a range of tests to identify what’s causing the symptoms, such as blood tests, cultures (tests to grow and identify bacteria or viruses), CT scans (like an inside-view x-ray), chest x-rays or MRI scans (which provide detailed imaging of the body’s organs), but it can still be hard to know that rabies is the cause.

Rabies can sometimes be confirmed if the virus is found in a saliva sample or if a specific blood test detects the presence of rabies antibodies (proteins the body makes to fight an infection). Alternatively, the virus might be found in the cerebrospinal fluid (or CSF, the fluid around your brain and spinal cord).

Another approach to diagnosing rabies involves taking a tissue biopsy from the neck and applying a special stain that makes the virus easier to see under a microscope. But even with these tests, it can still be hard to confirm a rabies diagnosis, since no single test is always 100% accurate. This makes it critical for doctors to be highly alert to the possibility of rabies, especially as it’s quite rare in developed countries.

One way to avoid unnecessary treatment is to test the animal that might have caused the exposure. If the animal can be euthanized and tested, and turns out not to have rabies, then there would be no need to give rabies post-exposure preventative treatment to the person who was bitten. Officials in public health can often help with this type of testing.

Treatment Options for Rabies

Rabies is a disease that doesn’t have a known cure. Rather, the main approach to rabies is focusing on prevention which includes vaccination for domestic animals, spreading awareness, and constant monitoring. If an individual is exposed to rabies, the first step to treatment is wound care which in itself is almost 100% effective if started within 3 hours of exposure. This involves thoroughly cleaning the wound with soap and water, and using a substance such as benzalkonium chloride or povidone-iodine that can kill the viruses.

In the US, if an individual gets a bite from a bat, skunk, raccoon, or a fox, they should immediately receive treatment, including the rabies vaccine and a treatment known as rabies immune globulin. If someone gets bitten by another type of animal, they should contact their local health department. Outside the United States, getting bitten by a dog also necessitates immediate treatment with a vaccine and rabies immune globulin.

How rabies is treated also depends on whether the patient has been vaccinated against rabies before. If they have been vaccinated, they might receive a specific vaccine on the day they were exposed to rabies and three days after.

If the patient has not been vaccinated before, they’re treated with specific rabies vaccines and also given a treatment called human rabies immune globulin, which helps the body fight against the rabies viruses. The human rabies immune globulin is injected directly into and around the wound, with any remaining amount given in a separate area to the vaccine injections.

Recently, the United States updated recommendations about people who wake up to find a bat in their room—they should get immediate immunization, as bats are a major source of rabies there.

If a doctor suspects rabies, they should also consider testing for other conditions that can have similar symptoms. These include:

Mental health conditions, specifically psychosis
Seizures
Poisoning caused by belladonna alkaloids, which are specific plant-based toxins
Stroke, which is a sudden interruption in the blood supply of the brain
Jacob Creutzfeldt disease, a rare and degenerative brain disorder
Brain tumor, an abnormal growth of cells in the brain
Encephalitis, which is inflammation of the brain
Tetanus, a serious bacterial infection that causes muscle stiffness and spasms

Possible Complications When Diagnosed with Rabies

The complications from rabies can be serious and many. They can include:

Seizures, which are sudden and uncontrolled electrical activities in the brain.
Fasciculations, or involuntary muscle twitching.
Psychosis, a condition that interferes with a person’s thinking, perception of reality, and emotions.
Aphasia, a condition that impairs the ability to comprehend or articulate language.
Autonomic instability, a condition where the part of the nervous system that controls mandatory functions like heart rate and body temperature becomes unstable.
Paralysis, or loss of the ability to move one or more muscles.
Coma, a state of deep unconsciousness from which a person cannot be awakened.
Death.

Frequently asked questions

Rabies has a high mortality rate, causing up to 70,000 deaths each year worldwide. In the past, a bite from a rabid animal was almost always deadly. However, the development of a vaccine by Pasteur in 1885 has led to highly effective preventative measures in developed countries, resulting in only about two deaths per year from rabies in the United States.

Rabies can be transmitted through the bite of an infected mammal or through contact with the saliva of an infected animal coming into contact with broken skin or mucous membranes. It can also be spread through inhalation, ingestion, from a mother to a baby during pregnancy, or during an organ transplant.

The signs and symptoms of Rabies include: - Incubation period: This is the time from when a person is bitten to when the first symptoms appear. - Prodrome phase: Symptoms during this phase are similar to the flu, such as body aches, fever, and stomach problems. - Acute neurologic illness: There are three types of neurological symptoms that can occur at this stage: - Encephalitic ("furious") form: Symptoms include fear of water or air, mental changes, agitation, increased reflexes, rapid heartbeat, rapid breathing, neck stiffness, and a positive Babinski's sign. - Paralytic ("dumb") form: Symptoms include weakness, mental changes, ongoing fevers, and bladder dysfunction. This form is often confused with Guillain-Barre syndrome. - Rare non-classic form: Symptoms include seizures and severe motor and sensory symptoms. - Coma stage: The person often slips into a coma at this stage, usually 10 days after the third phase. Symptoms may include intense fear of water, periods of not breathing, and muscle weakness. - Death: After the onset of the coma stage, death usually occurs within 2 to 3 days due to heart and lung failure. Rabies is almost always fatal. Recognizing these symptoms as early as possible is crucial, as rabies is almost always fatal once symptoms appear.

The types of tests that are needed for diagnosing rabies include: 1. Blood tests: These tests can detect the presence of rabies antibodies, which are proteins produced by the body to fight the infection. 2. Cultures: Cultures are performed to grow and identify the rabies virus in a saliva sample or cerebrospinal fluid (CSF), which is the fluid around the brain and spinal cord. 3. CT scans, chest x-rays, or MRI scans: These imaging tests provide detailed images of the body's organs and can help identify any abnormalities associated with rabies. 4. Tissue biopsy: A tissue biopsy from the neck can be taken and stained to make the rabies virus more visible under a microscope. It is important to note that no single test is always 100% accurate in diagnosing rabies, so doctors need to be highly alert to the possibility of rabies and consider the patient's symptoms and exposure history. Additionally, testing the animal that caused the exposure can also be helpful in determining the need for post-exposure preventative treatment.

The other conditions that a doctor needs to rule out when diagnosing Rabies are: - Mental health conditions, specifically psychosis - Seizures - Poisoning caused by belladonna alkaloids, which are specific plant-based toxins - Stroke, which is a sudden interruption in the blood supply of the brain - Jacob Creutzfeldt disease, a rare and degenerative brain disorder - Brain tumor, an abnormal growth of cells in the brain - Encephalitis, which is inflammation of the brain - Tetanus, a serious bacterial infection that causes muscle stiffness and spasms

The side effects when treating Rabies can include: - Seizures, which are sudden and uncontrolled electrical activities in the brain. - Fasciculations, or involuntary muscle twitching. - Psychosis, a condition that interferes with a person’s thinking, perception of reality, and emotions. - Aphasia, a condition that impairs the ability to comprehend or articulate language. - Autonomic instability, a condition where the part of the nervous system that controls mandatory functions like heart rate and body temperature becomes unstable. - Paralysis, or loss of the ability to move one or more muscles. - Coma, a state of deep unconsciousness from which a person cannot be awakened. - Death.

A general practitioner or infectious disease specialist.

Rabies causes between 30,000 to 70,000 deaths globally each year, mostly in less developed countries.

Rabies is treated through a combination of wound care, vaccination, and immune globulin treatment. If an individual is exposed to rabies, the first step is to clean the wound thoroughly with soap and water. Then, a substance such as benzalkonium chloride or povidone-iodine is used to kill the viruses. Treatment also depends on whether the patient has been vaccinated before. If they have been vaccinated, they might receive a specific vaccine on the day of exposure and three days after. If the patient has not been vaccinated, they are treated with specific rabies vaccines and human rabies immune globulin, which is injected directly into and around the wound.

Rabies is a disease that leads to viral encephalitis, affecting the brain and causing up to 70,000 deaths worldwide each year.

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