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Rabies

Rabies is a fatal viral infection that targets the brain and nervous system. The disease is zoonotic i.e. it can be transmitted from one species to another, such as from dogs to humans, commonly following a bite from an infected animal. For a human, rabies is almost always fatal if post exposure prophylaxis (PEP) is not administered immediately following an exposure. The rabies virus infects the central nervous system, ultimately affecting the brain and resulting in death. The rabies virus travels to the brain through the peripheral nerves. The incubation period of the disease i.e. the time lag between the bite/exposure to rabies and onset of symptoms of the disease,  is usually about a few days to few months in humans, depending on the  site  and severity of exposure, the   distance the virus must travel to reach the central nervous system and other factors .

National Rabies Control Programme

The content of this module has been validated by Dr M.K. Sudarshan, Rajiv Gandhi Institute of Public Health and Centre for Disease Control, Bangalore on 9th March 2015

 

The period between infection and the first flu-like symptoms is typically 2 to 12 weeks.  Initially the symptoms usually include one or more of the following:
  • Anxiety
  • Insomnia
  • Confusion
  • Agitation
  • Fever
  • Headache
  • Nausea and vomiting 
This shall soon be followed by:- 
  • Inability to drink water and / or fear for water ( hydrophobia )
  • Fear for draught of air ( aerophobia )
  • Fear for light ( photophobia ) 
  • Abnormal  behaviour
  • Hallucinations progressing to delirium 
  • Violent behaviour, in some 
  • Slight or partial paralysis
  • Ultimately leading to cardio-respiratory failure and death 
 

The rabies virus belongs to a group of viruses called lyssaviruses, which can infect mammals. The virus is present in the saliva of rabid animal.

Tests used to confirm a diagnosis of rabies in its more advanced stages include:
  • Skin biopsy A small sample of skin is removed and checked for the presence of the rabies virus.
  • Saliva test – A sample of saliva is tested for the presence of the rabies virus.
  • lumbar puncture – A needle is used to remove a small sample of cerebrospinal fluid (CSF), which can be checked for the rabies antibodies (CSF is the fluid that surrounds your brain and spinal cord).
  • Blood tests Blood is checked for the rabies antibodies.
 

Treatment depends upon the whether the patient has started to show any signs and symptoms. Presently the treatment involves providing life-supporting services in intensive care facilities and other palliative measures

a. Pre-exposure vaccination/prophylaxis : 
A vaccination that offers protection against rabies is recommended for people who are at risk. The rabies vaccines available are as follows: human diploid cell vaccine (HDCV), purified chick embryo cell vaccine (PCECV) and purified verocell rabies vaccine (PVRV). The vaccine may be administered either by intramuscular or intradermal route. The vaccines approved by the national health authorities shall be used for the intradermal route. 
 
The schedule for rabies vaccine is as follows:
  • The first dose is given on any chosen day (counted as day zero).
  • The second dose should be given seven days later.
  • The third dose should be given 21 or 28 days after the first dose.
  • For  those individuals who continue to be at increased risk of contracting rabies based on the advice of the rabies expert or infectious diseases specialist, booster doses of vaccine are recommended every two years or at suitable intervals to maintain protective antibody levels in such individuals. 
 
b. Post –exposure prophylaxis  (PEP) : 
Immunization or sero-vaccine therapy after exposure is highly successful in preventing the disease if administered promptly immediately or as early as possible. It includes:-
  • Thorough cleansing of the wound/s with water and soap or detergent and applying an anti-septic like povidone iodine or others. 
  • Administering rabies immunoglobulin, following severe exposures to rabies i.e. Category III exposures according to World Health Organization (WHO) – a special preparation of anti-rabies antibodies, into and around the wounds, as anatomically feasible.
  • Administering a course of modern rabies vaccine using “Essen” regimen consisting of five injections by intramuscular (into the muscle) route given on days 0 (day of first injection and may not be the day of exposure/bite), 3,7,14 and 28; or by intra-dermal  ( into the skin )  route, given on days 0 (day of first injection and may not be the day of exposure/bite), 3, 7 and 28. Only the rabies vaccines approved by the national health authorities shall be used for use by the intra-dermal route. 
c. Rabies vaccination to international travelers :
It is generally advisable to avoid touching all animals, including wild animals and   pets.    Pets in rabies infected countries may not be vaccinated against rabies. .Also free roaming stray dogs and other animals are a source of infection of rabies. The availability and access to life-saving rabies biologicals in these areas is a matter of serious concern.   Hence, many rabies free countries recommend pre-exposure vaccination to their citizens before they travel to rabies infected countries. 
 

www.unicef.org/rabies
www.immunizationinfo.org/rabies

www.vaccineindia.org

www.apcri.org

 

Rabies can spread to humans from infected animals through bite, scratch, or lick to broken skin or the eye. Once rabies virus enters the body, it multiplies before entering through the nerve endings. It then travels to the central nervous system i.e.  spinal cord and brain. Once the virus is in the central nervous system, it spreads to the salivary glands, lungs, kidneys and other organs. While in theory it is possible for rabies to be transmitted between humans, this has so far only happened as a result of donated infected organs like cornea, kidney and lungs.

  • CREATED / VALIDATED BY : NHP CC DC
  • LAST UPDATED ON : Jan 20, 2016

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