RABIES VIRUS: A Global View
Rabies is a viral disease caused by rabies virus which can be prevented by its vaccine only. It affects more than 75% countries of the world. Dogs are the main source of human rabies deaths. They contribute up to 99% of all rabies transmission to human rabies. Elimination is feasible through vaccination of dogs and prevention of dog bites.
Infection causes approx. 59,000 deaths every year, mostly in Asia and Africa. 40% of people bitten by suspect rabid(an animal infected with rabies virus) animals are children under 15 years of age.
Immediately thorough cleansing of the wound with soap and water after contact with a suspect rabid animal can saves lives.
WHO, the Food and Agriculture Organization of the United Nations (FAO), The World Organisation for Animal Health(OIE), and the Global Alliance for Rabies Control have set a global Target of “ Zero deaths by 2030”.
CAUSES OF RABIES:
The bite of a rabid animal( animals that spread rabies) is the most common cause of rabies. The rabid animals carry the rabies virus in their saliva and are able to enter the body through an opening in the skin, such as bite wound.
It is a rare possibility to get rabies from a non-bite exposure. For example, non-bite exposure includes inhalation of aerosol particles of the virus, or by a rabid animal licking a person’s nose, mouth, eyes, or broken skin.
How Rabies Virus Works?
The rabies virus is found in the nervous tissues of infected animals. As the virus travels its way to the brain, it begins to be secreted in the saliva of the animal. People get rabies when infectious saliva enters into the body, usually through a bite from an infected animal.
Rabies is usually transmitted by the bite of an infected animal to muscle tissue of the new host. From there, the virus travels all the way to the brain where it multiplies and causes the usually fatal disease.
Rabies Virus Travel Speed?
The transport system in nerve cells is hijacked by the virus to reach the brain with maximal speed and efficiency. When the speed of transport measured by researchers, they found that when rabies virus is transported with p75NTR[ a protein which is found on the tips of peripheral neurons and known to bind a small molecule called NGF (for nerve growth factor)], it moves at about 8 centimeters (slightly more than 3 inches) per day.
How Does Rabies Affect The Central Nervous System?
The rabies virus affects the central nervous system(CNS) including spinal cord and the brain of humans. During the incubation period, which is the time between contracting the virus and the appearance of symptoms, the virus travels along with the nerves towards the brain.
This process takes at least 10 days, but may (uncommonly) take as long as 1 year (In few cases it has occurred as long as 7 years after exposure, but the reasons for this long latency are unknown).
The infection causes inflammation(swelling) of the brain and spinal cord that can lead to encephalopathy(a type of brain disease that changes the brain’s function or structure) and, later, death.
According to WHO estimates 59,000 deaths recorded from rabies each year and out of which approximately 20,000 are alone from India. The initial rabies symptoms are often unambiguous and as a result, can be mistaken for other ailments. They include:
- Feeling unwell
- Feeling scared or anxious
- Pain & tingling at the site of injury
Rabies symptoms typically last for 2 to 10 days then main symptoms begin to develop like:
- Aggressive behaviour
- Hallucination (delusion or illusion)
- Hydrophobia (scaring from water)
- Excessive saliva production
Once a person starts showing symptoms and signs of rabies, the disease is nearly always fatal. For this reason, anyone who may have a risk of rabies exposure should have rabies vaccination for protection.
No test is available to detect the early stages of rabies infection. If you have been bitten by domestic or a wild animal who has not vaccinated, the doctor will advise you to administer a preventive shot of rabies vaccine to inhibit the infection before the symptoms set in. Getting the Rabies vaccine is the only key to avoiding the disease.
At government Hospital, 95% of animal bite cases are dog bites. The Hospital receives 50 -70 cases of animal bites per day, Dr. Raghunanthanan, professor of Madras Medical College(MMC) said.
“People should not wait to see the dog lives for 10 days as it founded in many cases or If the animal that bit you can’t be found. It may be the safest to assume that the animals have rabies. People should receive a series of shots to prevent the rabies virus from infecting them.”, Dr. Raghunanthanan added.
Rabies VaccineThe first step for rabies treatment to reduce the similar developing symptoms(See- How to treat the wound to reduce animal bite infection?) is to wash the wound thoroughly with soap and water for near 15 minutes. The next critical step to prevent rabies includes a dose of immunoglobulin (HRIG or ERIG) against the rabies virus followed by a strict schedule of injections of the rabies vaccine.
Doses Of Rabies Vaccines:
To prevent rabies, five doses of anti-rabies vaccine (RABIPUR or VERORAB) are administered on the 0, 3, 7, 14 and 28th days of the bite. The immunoglobulin provides immediate protection against the virus to “bridge the gap” until the vaccine starts working (In some countries immunoglobulin is not available, in that case, you can start treatment directly from rabies vaccines).
The vaccine helps the immune system of the person to produce antibodies against the potentially lethal virus.
People such as cattle farmers or veterinarians who work with potentially infected animals or humans need to be vaccinated against rabies. They will also have periodic blood tests to see whether the booster shot of the rabies vaccine is needed by them.
[This vaccine is not advisable to keep in your First Aid Kit]
Rabies is a preventable disease. There are some simple measures you can take to help keep you from catching rabies:
- Vaccinate your pets
- Keep your pets from roaming outside
- Avoid contact with wild animals do not feed them and stay at a safe distance when observing them
- do not bring home wild animals
- Prevent bats from entering living spaces or other structures near your home.
- Supervise children and teach them not to approach or touch animals they do not know
- stay away from animals showing signs of rabies
You should report any signs of an infected animal to your local animal control department or Municipal Corporation.