An introduction to Rabies (Hydrophobia)
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Dr Asem Suresh Kumar Meitei
Rabies is the most devastating viral disease of all warm blooded animals and a disease of great antiquity as well as one of the most dreaded and stub-born zoonoses. The disease is one of the oldest known to mankind and most feared of human diseases, well recognized already in early Middle Eastern Civilizations where it was e.g. mentioned in the Eshnunna code dating to before 2300 B.C. or in the Iliad (about 700 B.C.) where Achilles called Hector a “rabid dog”. As early as,existence of rabies is shown in the sketches and drawings of mad dogs left by ancient Egyptians, Greeks and Romans. It was known to Homer and is mentioned in Greek Mythology. Aristotle, who was thought to be the first to describe the symptoms of the disease, believed that all animals bitten by mad dogs would become rabid.
Transmission of rabies from rabid to a normal dog through inoculation of saliva was demonstrated by Zinke and Gurner in 1804 and also by Salm- Reifferscheidt in 1813 respectively.
Until Zinke, in 1804, demonstrated the infectiousness of saliva of a rabid dog, several contradictory theories were formulated to explain the causes and origin of rabies. Some believed that it arose spontaneously whereas other associated it with hot and cold weather, irregular weather conditions, hot food, lack of drinking water, unsatisfied sexual desire and violent nervous excitement.
Aetiology
Rabies is caused by a neurotropic RNA virus, which resembles a bullet in shape and is classification of the family Rhabdoviridae and genus Lyssavirus. The virus is highly susceptible to light and heat and to pH values d” 3 or e” 11, and rabies virus can be readily inactivated by various chemical agents, such as phenol, chloroform, ether, formalin, potassium permanganate, soft soap, etc. But, the rabies virus is remarkably resistant to putrefaction, decay, cold, dryness and autolysis. The rabies virus is highly resistant against cold, dryness and decay. The virus may remain viable in autolysed brain for 9 (nine) days. Animal cadavers may remain infectious for weeks.
Rabies can be summarized as a very dreaded and highly fatal infectious disease of man and animals characterized by marked nervous disturbances, such as increased excitability and irritability, impairment of consciousness and finally paralysis resulting in death. Once the disease is established in man there is no cure of it; death is the outcome i.e. death from rabies is 100 percent.
Rabies (‘rabidus’ means ‘mad’) is also known as hydrophobia (the very commonly used term to describe rabies in humans), lyssa, lytta, habhos, tollwut, rage, dierringue, hondsdolheid, etc. in different parts of the world.HYDROPHOBIA (hydro= water; phobia= fear) results from the painful spasms of the pharyngeal muscles (the muscles responsible for swallowing of water or food).
(To be contd)
Rabies is the most devastating viral disease of all warm blooded animals and a disease of great antiquity as well as one of the most dreaded and stub-born zoonoses. The disease is one of the oldest known to mankind and most feared of human diseases, well recognized already in early Middle Eastern Civilizations where it was e.g. mentioned in the Eshnunna code dating to before 2300 B.C. or in the Iliad (about 700 B.C.) where Achilles called Hector a “rabid dog”. As early as,existence of rabies is shown in the sketches and drawings of mad dogs left by ancient Egyptians, Greeks and Romans. It was known to Homer and is mentioned in Greek Mythology. Aristotle, who was thought to be the first to describe the symptoms of the disease, believed that all animals bitten by mad dogs would become rabid.
Transmission of rabies from rabid to a normal dog through inoculation of saliva was demonstrated by Zinke and Gurner in 1804 and also by Salm- Reifferscheidt in 1813 respectively.
Until Zinke, in 1804, demonstrated the infectiousness of saliva of a rabid dog, several contradictory theories were formulated to explain the causes and origin of rabies. Some believed that it arose spontaneously whereas other associated it with hot and cold weather, irregular weather conditions, hot food, lack of drinking water, unsatisfied sexual desire and violent nervous excitement.
Aetiology
Rabies is caused by a neurotropic RNA virus, which resembles a bullet in shape and is classification of the family Rhabdoviridae and genus Lyssavirus. The virus is highly susceptible to light and heat and to pH values d” 3 or e” 11, and rabies virus can be readily inactivated by various chemical agents, such as phenol, chloroform, ether, formalin, potassium permanganate, soft soap, etc. But, the rabies virus is remarkably resistant to putrefaction, decay, cold, dryness and autolysis. The rabies virus is highly resistant against cold, dryness and decay. The virus may remain viable in autolysed brain for 9 (nine) days. Animal cadavers may remain infectious for weeks.
Rabies can be summarized as a very dreaded and highly fatal infectious disease of man and animals characterized by marked nervous disturbances, such as increased excitability and irritability, impairment of consciousness and finally paralysis resulting in death. Once the disease is established in man there is no cure of it; death is the outcome i.e. death from rabies is 100 percent.
Rabies (‘rabidus’ means ‘mad’) is also known as hydrophobia (the very commonly used term to describe rabies in humans), lyssa, lytta, habhos, tollwut, rage, dierringue, hondsdolheid, etc. in different parts of the world.HYDROPHOBIA (hydro= water; phobia= fear) results from the painful spasms of the pharyngeal muscles (the muscles responsible for swallowing of water or food).
(To be contd)