Knowledge Bank
While its precise origins are unknown, rabies is thought to derive from rabhas, Sanskrit for "to do violence." Others trace its origins to Latin, rabis - "rage" or rabere - "to rave."
There are two forms of rabies. "Furious" rabies, the most common form, affects primarily the brain stem, causing the victim to become aggressive or excitable. The less common form, "paralytic" or "dumb" rabies, affects the spinal cord and can result in weakness, lethargy and the inability to move, speak or make sounds.
Rabies is most often transmitted as the result of a bite or scratch when the saliva of an infected animal enters the skin. The resulting viral infection attacks the victim's central nervous system.
The incubation period for rabies — the time between infection and the appearance of symptoms — can range from a few weeks to a year or longer in humans, although 30 to 50 days is more common. Animals usually develop symptoms 20 to 60 days after exposure. The incubation period depends on the dose of virus received and the location of the bite or contact.
Following infection, a series of worsening symptoms develop. Initial complaints resemble those of a cold or flu — fever, headaches, and muscle pain — but as brain function is affected, symptoms quickly worsen. The victim may experience agitation or irritability; loss of muscle control or paralysis, usually beginning in the legs; depression; and confusion.
When the virus affects the nerves of the salivary glands, it causes painful spasms of the throat and voice box. A sip of water can trigger these spasms, leaving the victim fearful of drinking — explaining why rabies is sometimes referred to as "hydrophobia," the fear of water. The infected salivary glands begin to produce too much saliva, which causes the appearance of foaming around the mouth associated with rabies. Coma and death usually occur within three to 20 days of the onset of symptoms. Once the rabies symptoms become apparent, no cure is known. The only palliative care is constant anaesthesia, to avoid the extremely painful spasms of all limbs.
Further information:
World Health Organization (WHO) Rabies Fact Sheet:
http://www.who.int/mediacentre/factsheets/fs099/en/
National Institutes of Health (NIH) Medline Plus information on rabies:
http://www.nlm.nih.gov/medlineplus/rabies.html
MEDIVISION India's information on rabies:
http://www.medivisionindia.com/infectiousdisease/diseases.phtml?id=428
Rabies still represents an important public health problem in Asia. 56% of reported human rabies deaths occur in Asia, and India alone accounts for 65% of those. Nevertheless, in the field of communicable diseases, rabies ranks far behind the current and future top priorities of organizations such as World Health Organisation when considering their public health impact.
There is no mandated reporting for rabies cases of human or animal rabies in India, and laboratory diagnosis is very rarely made in both humans and animals; therefore, accurate mortality data are unknown. As a result, rabies is ranked low on the priority list for disease control programs [when considering their public health impact expressed in terms of mortality, morbidity and disability adjusted life years (DALYS)].
Underestimating the health implications of rabies leads many high-ranking decision makers in public health and animal health to perceive rabies as a rare disease of humans resulting from the bite of an economically unimportant animal (the dog). Therefore, rabies usually falls between two stools, and is not dealt with appropriately either by the Ministry of Health or the Ministry of Agriculture.
For all of these reasons, rabies is a neglected disease, yet has many of the characteristics of a disease on which one could have a significant and rapid impact. Rabies is an entirely preventable disease. It is a vaccine-preventable disease (in humans and animals), and the expertise to formulate strategies to successfully eliminate rabies is available.
Nevertheless pre-exposure anti-rabies vaccine has been available for high-risk groups, including children and pet owners, since 1967 and yet globally, only 1.5 million people have been immunized. Many of the countries particularly affected by rabies can afford only the less effective and relatively dangerous nerve tissue vaccines.
Among human infections, rabies is the tenth leading cause of death and today more people die from rabies than from yellow fever, dengue and Japanese encephalitis combined.
Further information:
WHO's Department of Communicable Disease Surveillance and Response (CSR):Wild animals are the natural reservoir of rabies and responsible for the spread of the disease. Any mammal can get rabies. The most common wild reservoirs of rabies are raccoons, skunks, bats, and foxes. Domestic mammals can also get rabies such cats, cattle, and dogs.
Feral, semi-restricted and restricted dogs are responsible for more than 99% of all human rabies cases in India; 17.4 million people were bitten by animals in 2002 and every 20 seconds a person undergoes post-exposure treatment. Elimination of rabies in humans requires control of rabies in dogs. Dogs can be infectious to others for as much as two weeks before symptoms appear. Estimates suggest that by preventing rabies in a single dog, 211,000 additional infections can be avoided. Elimination of rabies in humans requires control of rabies in dogs.
People usually get rabies from the bite of a rabid animal. Rabies is a disease of young people, mostly affecting the 5-15 age class, as dog bites to the face, head, neck and upper extremities carry the greatest risk of infection. Although very rare, it is also possible to face non-bite exposure, if eyes, nose, mouth, open wounds, scratches, abrasions or mucous membranes come into contact with contaminated saliva or other potentially infectious materials (such as brain tissue).
Inhalation of aerosolized rabies virus is also a potential non-bite route of exposure, but other than laboratory workers, most people are unlikely to encounter an aerosol of rabies virus. Contact such as petting a rabid animal does not constitute an exposure.
The only documented cases of rabies caused by human-to-human transmission occurred among 8 recipients of transplanted corneas, and among three recipients of solid organs. Casual contact, such as touching a person with rabies or contact with non-infectious fluid or tissue (urine, blood, and faeces) does not constitute an exposure and does not require treatment.
Medical assistance should be obtained as soon as possible after an exposure. One of the most effective methods to decrease the chances for infection involves thorough washing of the wound with soap and water.
For post-exposure treatment, a regimen of one dose of immune globulin and five doses of rabies vaccine over a 28-day period is required. Rabies immune globulin and the first dose of rabies vaccine should be administered as soon as possible after exposure. Additional doses or rabies vaccine should be given on days 3, 7, 14, and 28 after the first vaccination. It is important that the proscribed schedule of shots is accurately followed. Current modern vaccines are relatively painless and are given in your arm, like a flu or tetanus vaccine.
A pre-exposure vaccination does not eliminate the need for additional therapy after a rabies exposure. It simplifies therapy by eliminating the need for human rabies immune globulin (HRIG) and decreasing the number of doses needed. A pre-exposure vaccination is important for people at high risk of being exposed to rabies in areas where immunizing products may not be readily available resulting in delayed treatment.
Further information:
Centers for Disease Control & Prevention (CDC) rabies vaccine publication:Rabies is found on all continents except Antarctica. In certain areas of the world, canine rabies remains highly endemic, including (but not limited to) parts of Brazil, Bolivia, Colombia, Ecuador, El Salvador, Guatemala, India, Mexico, Nepal, Peru, the Philippines, Sri Lanka, Thailand, and Vietnam.
The disease is also found in dogs in most of the other countries of Africa, Asia, and Central and South America, except as noted in the table below, which lists countries that have reported no cases of rabies during the most recent 2-year period for which information is available (formerly referred to as “rabies-free countries”).
Latest information can be obtained from the World Health Organization, Centers for Disease Control and Prevention, your local health authority, or embassy/consulate offices when you are abroad.
Countries and political units reporting no cases of rabies during 1999* |
|
Region |
Countries |
Africa |
Cape Verde, Libya, Mauritius, Réunion, São Tome and Principe, and Seychelles |
Americas |
North: Bermuda, St. Pierre and Miquelon |
Asia |
Armenia, Cyprus, Hong Kong, Japan, Kuwait, Lebanon, Qatar, and Singapore |
Europe |
Albania, Finland, Gibraltar, Greece, Iceland, Ireland, Isle of Man, Italy, Malta, Norway (mainland), Portugal, Spain* (except Ceuta/Melilla), Sweden, Switzerland, and United Kingdom |
Oceania † |
Australia,* Cook Islands, Fiji, French Polynesia, Guam, Hawaii, Kiribati, Micronesia, New Caledonia, New Zealand, Palau, Papua New Guinea, Samoa, and Vanuatu |
* Bat rabies exists in some areas that are free of terrestrial rabies. |
|
Travellers to rabies-endemic countries should be warned about the risk of acquiring rabies, although rabies vaccination is not a requirement for entry into any country.
RiskTravellers with extensive unprotected outdoor, evening, and night time exposure in rural areas, such as might be experienced while bicycling, camping, or engaging in certain occupational activities, might be at high risk even if their trip is brief.
Animals in general tend to avoid human beings, but they can attack, particularly if they are protecting their young or territory. Travellers should be reminded that, in areas of endemic rabies, domestic dogs, cats, or other mammals should never be petted, handled, or fed. Wild animals should be avoided; most injuries from wild animals are the direct result of attempting to pet, handle, or feed the animals.
Travellers should be advised that any animal bite or scratch should receive prompt local treatment by thorough cleansing of the wound with copious amounts of soap and water and a povidone-iodine solution if available; this local treatment will significantly reduce the risk of rabies.
Travellers who might have been exposed to rabies should be advised to always contact local health authorities immediately for advice about post exposure prophylaxis and should also contact their personal physician as soon as possible thereafter.
(Source: Health information for International Travel: CDC Yellow Book, 2003-2004)
