If treated immediately after a bite, it is possible to prevent rabies. Once a person begins showing signs and symptoms of rabies, the disease is nearly always fatal. For that reason, vaccines to stop the rabies virus from infecting the body are given to anyone who may have a risk of contracting rabies.
According to Medilexicon's medical dictionary:
Rabies is "Highly fatal infectious disease that may affect all species of warm-blooded animals, including humans; transmitted by the bite of infected animals including dogs, cats, skunks, wolves, foxes, raccoons, and bats, and caused by a neurotropic species of Lyssavirus, a member of the family Rhabdoviridae, that has tropism for the central nervous system and the salivary glands; inhalation infection possbile (aerosolized virus in bat caves, attics). The symptoms are characteristic of a profound disturbance of the nervous system, excitement, aggressiveness, and madness, followed by paralysis and death. In animals, clinical signs are variable, and sometimes drooling and tongue paralysis are the only signs. Transmission of the virus can occur before clinical signs are expressed. Characteristic cytoplasmic inclusion bodies (Negri bodies) found in many neurons aid rapid laboratory diagnosis."
The term is derived from the Latin "rabies" meaning "madness". All human cases of rabies were fatal until a vaccine was developed in 1885 by Louis Pasteur and Émile Roux. Treatment after exposure, known as post-exposure prophylaxis (PEP), is highly successful. A recombinant vaccine called V-RG has been successfully used to prevent outbreaks of rabies in wildlife. Currently pre-exposure immunization has been used in both human and non-human populations. In many countries domesticated animals are required to be vaccinated.
In the United States, animals most likely to transmit rabies include bats, coyotes, foxes, raccoons and skunks. In developing countries of Africa and Southeast Asia, stray dogs are the most likely to spread rabies to people.
Since the widespread vaccination of domestic dogs and cats and the development of effective human vaccines and immunoglobulin treatments, the number of recorded deaths from rabies has dropped in the United States. The reported cases are mostly caused by bat bites, which may go unnoticed by the victim and as a result are untreated.
How common is rabies?
The World Health Organization (WHO) estimates that more than 55,000 people worldwide die from rabies every year, as a result of being bitten by a rabid animal.A person does not have to be bitten to get rabies; a scratch that is licked by an infected animal is enough to cause the disease.
High risk areas
Rabies is widespread in many countries worldwide, but Asia, Africa and South America report more cases of human deaths from rabies. The largest number of human deaths from rabies is reported in India.
Bat rabies
There are two strains of rabies-like viruses found in bats across Northern Europe. These are known as European Bat Lyssaviruses (EBLVs) 1 and 2. They are commonly referred to as bat rabies. People are not at risk if they have no direct contact with bats.
What are the signs and symptoms of rabies?
A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom, while dilated pupils may be a sign.It can take from one week to more than a year for symptoms of rabies to appear after infection. But the average time of the incubation period is four to eight weeks. The closer the bite is to the head, the shorter the incubation period. A bite to the face, head or neck will have a shorter incubation time than a bite to the arm or leg.
If an animal bite is not treated in time, rabies will start with pain or tingling at the site of the bite with fever, loss of appetite and headache. Early-stage symptoms of rabies are malaise, headache and fever, progressing to acute pain, violent movements, uncontrolled excitement, depression, and hydrophobia. Finally, the patient may experience periods of mania and lethargy, eventually leading to coma. The primary cause of death is usually respiratory insufficiency.
There are two ways in which rabies can develop which can lead to furious rabies or dumb rabies.
Symptoms of furious rabies:
There is a growing sense of anxiety, jumpiness, disorientation, neck stiffness, and sometimes seizures or convulsions. The pupils may appear dilated and there may be an increased sensitivity to sound, light and temperature.
Within a week, many infected people show a fear of swallowing. In spite of overwhelming thirst, any attempt to drink causes spasms of the throat muscles and diaphragm. This is called hydrophobia (fear of water). The patient has difficulty swallowing because the throat and jaw become slowly paralyzed, shows panic when presented with liquids to drink, and cannot quench his or her thirst.
As the disease worsens, there are intervals of deranged behavior with spitting, biting and delirium. It is in this phase that infected animals are highly aggressive and bite.
Delusions and hallucinations develop. These attacks alternate with periods of clear-mindedness when the person suffers acute anxiety and mental distress. Death almost invariably results two to ten days after the first symptoms; the few humans who are known to have survived the disease were all left with severe brain damage.
Symptoms of dumb rabies:
It is less common and affects the spinal cord. It causes muscle paralysis to spread across the body, leading to heart and lung failure. Total paralysis, coma and death follow in almost 100 percent of cases of rabies, usually about a week after the severe symptoms develop.
Rabies does not cause any signs or symptoms at first. It isn't until late in the disease, often just days before death that signs and symptoms appear:
- Agitation
- Anxiety
- Confusion
- Difficulty swallowing
- Excessive salivation
- Fear of water (hydrophobia) because of the difficulty in swallowing
- Fever
- Hallucinations
- Headache
- Insomnia
- Partial paralysis
Based on the injuries and situation in which the bite occurred, it will be decided whether treatment to prevent rabies should be received.
Seek medical attention, if you think there is a possibility you have been bitten. For instance, if a bat enters a bedroom at night or a bat has been in contact with a person who cannot report a bite, such as a small child or disabled person, assume that person has been bitten. Finding a bat in the room of a sleeping infant is regarded as an indication for post-exposure prophylaxis. A bite or exposure to the virus may occur while the victim is asleep and unaware or awake and unaware that a bite occurred.
What are the causes of rabies?
Rabies infection is caused by the rabies virus. The virus is spread through the saliva of infected animals. Infected animals can spread the virus by biting another animal or person.In rare cases, rabies can be spread when infected saliva gets into an open wound or the mucous membranes, such as the mouth or eyes.
Animals that can transmit the rabies virus
The animals most likely to transmit the rabies virus to people include:
Pets and farm animals
- Cats
- Cows
- Dogs
- Ferrets
- Goats
- Horses
- Rabbits
- Bats
- Beavers
- Coyotes
- Foxes
- Monkeys
- Raccoons
- Skunks
- Woodchucks
The virus
The virus remains at the site of the bite, before it enters the body and multiplies in the muscle cells near the bite wound. The virus then enters the nerve endings and travels to the spinal cord and brain. Once in the central nervous system, the virus spreads to the salivary glands, lungs, kidneys and other organs.
Incubation period
The incubation period is the time between the bite and the start of the symptoms. It varies with the distance of the bite from the head.
Bites on the head, face or neck may result in rabies developing over a short period. Bites further from the head are followed by a much longer incubation period.
Children may be at a greater risk from infection, as they are shorter in height. When travelling, they should be discouraged from petting unknown animals.
What are the risk factors of rabies?
Factors that can increase the risk of rabies include:- Activities involving contact with wild animals that may have rabies, such as exploring caves where bats live or camping where there are wild animals.
- Traveling or living in developing countries where rabies is more common, including countries in Africa and Southeast Asia.
- Working in a laboratory with the rabies virus.
- Wounds to the head or neck. This could increase the risk of the rabies virus travelling to the brain more quickly.
How is rabies diagnosed?
In some cases there is no way to know whether the animal is infected and has transmitted the rabies virus. For this reason, treatment to prevent the rabies virus from infecting the body is recommended if doctors think there is a chance of exposure to the virus.Blood and tissue tests are used to diagnose rabies in people who have signs and symptoms of the infection.
An animal suspected of having rabies should be captured and watched for 5 to10 days. If no symptoms of rabies have been observed, it can be assumed that the animal is not rabid. If the animal is killed or dies, its brain can be examined for the presence of the rabies virus.
What is the treatment for rabies?
It is important to know that a scratch that is licked by an infected animal is enough to cause rabies.Treatment after exposure, known as post-exposure prophylaxis (PEP), is highly successful in preventing the disease if administered promptly. Treatment should be immediate after the bite of an animal possibly infected with rabies. Rabies is fatal once symptoms develop. Medical advice should be sought for any animal bite, and a tetanus injection given.
Immediately after an animal bite
Symptoms can usually be prevented from developing if proper treatment is started immediately after being bitten. Early treatment is especially important following bites on the face. Immediately after being bitten:
- wash the wound thoroughly with soap and water under a running tap
- use antiseptic or alcohol to clean the wound
- leave the wound open, do not attempt to stitch it
- go to the nearest doctor or hospital and explain you have been bitten
If you have not been vaccinated
If you have not been vaccinated before you were bitten, human rabies immunoglobulin (HRIG), also known as passive immunization, will be injected around the bite to neutralize the virus before it gets into the body.
This substance binds to the virus so that the immune system can destroy it. In addition, a longer-lasting rabies vaccine (active immunization) should be given in 5 to 6 doses over 30 days. The vaccine is given into the arm and is relatively painless with minimal side effects.
If you are abroad and have been bitten by a suspect animal and cannot get the vaccine, you should return to your home country immediately for medical treatment.
If you have been vaccinated
If you have already been vaccinated before being bitten with the pre-exposure vaccine, two doses of the rabies vaccine will be given: one at the time of the bite, and one 3 to 7 days later. The body should respond to treatment quickly.
Anyone who has had intimate contact with an infected person should also be treated with the vaccine.
If the infected person is not treated and symptoms have developed, rabies is said to be established. In this situation, nothing can be done, except to keep them comfortable. They should be nursed in a darkened room and their symptoms kept under control with equipment and medication. Death is almost inevitable.
There is no specific treatment for rabies infection. Though a small number of people have survived rabies, the disease is usually fatal. For that reason, anyone thought to have been exposed to rabies receives a series of shots to prevent the infection.
Determining whether the animal that bit you has rabies
In some cases, it is possible to determine whether the animal has rabies before beginning the series of rabies shots. If it is determined that the animal is healthy, the shots are not needed.
Procedures for determining whether an animal has rabies vary by situation:
- Pets and farm animals. Cats, dogs and ferrets that bite can be observed for 10 days to see if they show signs and symptoms of rabies. If the animal remains healthy during the observation period, then it does not have rabies and the rabies shots are not needed. In some cases, pets and farm animals are considered on a case-by-case basis.
- Wild animals that can be caught. Wild animals that can be found and captured (such as a bat that came into a home) can be killed and tested for rabies. Tests on the animal's brain may reveal the rabies virus. If the animal does not have rabies, the shots will not be needed.
- Animals that cannot be found. If the animal cannot be found, the situation should be reviewed with a doctor and the local health department. In certain cases, it may be safest to assume that the animal had rabies and proceed with the rabies shots. In other cases, it may be unlikely that the animal had rabies and it may be determined that rabies shots are not necessary.
How is rabies prevented?
People travelling to an area where there is a risk of rabies or engaging in activities putting them at risk, may need a pre-exposure anti-rabies vaccination.The vaccination slows the development of rabies. If bitten by an infected animal, there will be more time to seek treatment.
The pre-exposure anti rabies vaccination consists of three injections over the course of a month. Booster injections every two years are needed for continued protection after that.
If travelling to a country where rabies exists, three injections will be needed (day 0, day 7 and day 28). Allow at least a month to finish the course before departure. The injections are given into the skin on the upper arm.
Pregnant women should avoid any unnecessary vaccinations. But if at risk of being exposed to rabies, it is recommended to have the vaccine.
Do not touch unknown animals
When travelling abroad, do not touch any unknown animals. Educate children about the dangers of petting unknown animals. This is especially true for animals that appear unusually tame, as this is an early sign of rabies in animals. Examine children daily for cuts and scratches and ask them how they got them. Make sure they know that being bitten by an animal is dangerous and they need to tell you about it.
Reduce the risk of coming in contact with rabid animals by following these recommendations:
- Do not approach wild animals. Wild animals with rabies may seem unafraid of people. It is not uncommon for a wild animal to be friendly with people. Stay away from any animal that seems unafraid.
- If traveling, consider the rabies vaccine. If traveling to a country where rabies is common and for a long period of time, ask your doctor whether you should receive the rabies vaccine.
- Keep bats away. Seal any cracks and gaps where bats can enter the home. If you know you have bats in your home, seek assistance from experts to find ways to keep bats out.
- Protect small pets from predators. Keep rabbits and other small pets, such as guinea pigs, inside or in protected cages so that they are safe from wild animals. Small pets cannot be vaccinated against rabies.
- Report stray animals to local authorities. Call local animal control officials or other local law enforcement to report stray dogs and cats.
- Supervise pets. Keep pets inside and supervise them when outside. This will help keep pets from coming in contact with wild animals.
- Vaccinate pets. Cats, dogs and ferrets can be vaccinated against rabies. Ask your veterinarian how often your pets should be vaccinated.
Facts about rabies
Reliable data on rabies is scarce in many areas of the world, making it difficult to assess its full impact on human and animal health.General advice for all countries:
Medical advice should be sought for any animal bite, and a tetanus injection given.
The UK: Strict quarantine regulations keep the country rabies-free. But bat bites should be medically treated.
Europe: In general, dogs in urban areas in mainland Europe are not rabid, but foxes can be. To combat rabies in foxes, vaccines are left in bait or dropped from helicopters onto fields.
India, Afghanistan, Vietnam, Africa, Central and South America and Thailand: Many dogs in these areas are infected with rabies, but there have been recent decreases in human rabies, due to improved vaccination programs. Any bite from an animal, particularly dog, cat, monkey or bat, should be treated as a possible rabies risk.
Australia: Australia is mostly rabies-free, but some bats may be infected so precautions should be taken.
Ireland, Japan, Norway, Sweden, New Zealand, the Antarctic, some Caribbean and Pacific islands, some parts of Europe: do not harbor rabies.
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