An introduction to Rabies (Hydrophobia)
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Dr Asem Suresh Kumar Meitei
Contd from previous issue
The patient is thirsty and desperately wants to drink water, but cannot do so due to painful spasms of the muscles. After few futile efforts to drink water, the patient develops a phobia (fear) or hatred to water, sight of which causes violent nervous disturbances.
Since, 1881, Louis Pasteur conducted a series of studies on it and made the epoch-making discovery that the central nervous system was actually the seat of infection of rabies. And, it was again Louis Pasteur and his co-workers, Chamberland and Roux, who in 1884 made another epoch-making discovery in the annals of rabies by the introduction of anti-rabies vaccine (ARV). As, in 1885, Louis Pasteur administered a graded vaccine to a boy severely bitten y a rabid dog, however, the boy was survived thereby marking a milestone in the development of modern medicine.
Epidemiology
The epidemiology of rabies varies depending on the vector species that is predominant in a given country or area of the world. The epidemiology can even vary a great deal within a given country depending on the vector species, rates of infection and interaction between the vector species. Age is also an important factor in the susceptibility of all species to rabies with younger animals being more susceptible than older animals. In India, dogs, mogooses, foxes, jackals, cats, wolves, bandicoots (pig rats or Malabar rats usually seen in the Deccan) and monkeys are considered to be vectors and reservoirs.
With the exception of Antarctica and Ocenia, rabies is enzootic (prevails constantly throughout the year) in all other continents of the earth. In Tasmania (Australia), however, one suspected (unconfirmed) case of rabies in a child and a dog was reported in 1867. New Zealand has no report of the disease. Britain, Hawaii, Scandinavia and few islands here and there are currently free from rabies. It is enzootic in the continental India. But, there is no record of rabies from Indian islands. But, most the Americas, Africa, Asia as well as Central and Eastern Europe are risk areas. The disease is enzootic in much of the U.S.A., particularly the Easter and southern states. It has become an important problem in Canada being carried down from the north to the populated areas largely by the migration of foxes, and has been diagnosed in dogs and foxes in Greenland.
Now in China, Indonesia, Malaysia, etc. rabies is one of the re-emerging diseases; this may be because of high dog population density and low vaccination coverage in dogs.. The high incidence of rabies leads to numerous concerns: a potential carrier-dog phenomenon, un- documented transmission of rabies virus from wildlife to dogs, counterfeit vaccines, vaccine mismatching, and sero-conversion testing in patients after their completion of post-exposure pro- phylaxis (PEP).
Several different types of carnivores of the canine and feline families have been proved to be vectors (transmitter of the disease with apparently showing symptoms of it) of rabies. Some species of carnivorous vectors, bats (vampire and insectivorous) and members of the Viverridae (Civet) family may act as Reservoirs (source of disease without necessarily showing apparent symptoms of the disease).
Dogs remain the principal vectors in Africa, Asia, Latin America and parts of Europe and continue to represent the principal source of bite wounds or contact infection in man. Other carnivorous vectors are wolves, jackals, foxes, mongooses, coyotes, skunks, badgers, cats and other members of feline family. Foxes are the principal vectors and as in Canada, Cattle are the principal receptors.
In North America skunks are the common vectors. Rabies occurs in most contries in African continent, but the reported incidence is surprisingly low for an area with such a high population of wild carnivores.
Rabies is not of major economic importance in farm animals, although individual herds and flocks may suffer many fatalities. The disease is always fatal. The prime importantce of rabies is its transmissibility to humans. Although, it may be possible for any type of animal to transmit rabies, infection is seldom due to bites inflicted by solipeds and ruminants. Birds are susceptible to rabies and there is at least one case of clinically diagnosed rabies in boy after bitten by a goose.
Rabies occurs in most countries of the world except in some islands. Australia and New Zealand have claimed non–existence of rabies. Britain, Hawwaii, and Scandinavian are currently claimed free from the disease. Britain had two minor out breaks in dogs involving one dog each year of 1969 and 1970 but the disease was controlled successfully. There is no report of occurrence of rabies from Indian islands.
Rabies is responsible for significant morbidity and mortality in India. The disease is endemic in the country, human and animal cases of rabies are reported from all over the country throughout the year except for Andaman & Nicobar and Lakshadweep Islands. In India, about 96% of the morbidity and mortality due to Rabies is associated with dog bites. Although, Rabies affects people of all age groups, children are the most vulnerable which constitutes 40% of the people exposed to dog bites in Rabies-endemic areas. As per WHO estimates, India accounts for 36% of the global and 65% of the human Rabies deaths in the Southeast Asia region.
(To be contd)
Contd from previous issue
The patient is thirsty and desperately wants to drink water, but cannot do so due to painful spasms of the muscles. After few futile efforts to drink water, the patient develops a phobia (fear) or hatred to water, sight of which causes violent nervous disturbances.
Since, 1881, Louis Pasteur conducted a series of studies on it and made the epoch-making discovery that the central nervous system was actually the seat of infection of rabies. And, it was again Louis Pasteur and his co-workers, Chamberland and Roux, who in 1884 made another epoch-making discovery in the annals of rabies by the introduction of anti-rabies vaccine (ARV). As, in 1885, Louis Pasteur administered a graded vaccine to a boy severely bitten y a rabid dog, however, the boy was survived thereby marking a milestone in the development of modern medicine.
Epidemiology
The epidemiology of rabies varies depending on the vector species that is predominant in a given country or area of the world. The epidemiology can even vary a great deal within a given country depending on the vector species, rates of infection and interaction between the vector species. Age is also an important factor in the susceptibility of all species to rabies with younger animals being more susceptible than older animals. In India, dogs, mogooses, foxes, jackals, cats, wolves, bandicoots (pig rats or Malabar rats usually seen in the Deccan) and monkeys are considered to be vectors and reservoirs.
With the exception of Antarctica and Ocenia, rabies is enzootic (prevails constantly throughout the year) in all other continents of the earth. In Tasmania (Australia), however, one suspected (unconfirmed) case of rabies in a child and a dog was reported in 1867. New Zealand has no report of the disease. Britain, Hawaii, Scandinavia and few islands here and there are currently free from rabies. It is enzootic in the continental India. But, there is no record of rabies from Indian islands. But, most the Americas, Africa, Asia as well as Central and Eastern Europe are risk areas. The disease is enzootic in much of the U.S.A., particularly the Easter and southern states. It has become an important problem in Canada being carried down from the north to the populated areas largely by the migration of foxes, and has been diagnosed in dogs and foxes in Greenland.
Now in China, Indonesia, Malaysia, etc. rabies is one of the re-emerging diseases; this may be because of high dog population density and low vaccination coverage in dogs.. The high incidence of rabies leads to numerous concerns: a potential carrier-dog phenomenon, un- documented transmission of rabies virus from wildlife to dogs, counterfeit vaccines, vaccine mismatching, and sero-conversion testing in patients after their completion of post-exposure pro- phylaxis (PEP).
Several different types of carnivores of the canine and feline families have been proved to be vectors (transmitter of the disease with apparently showing symptoms of it) of rabies. Some species of carnivorous vectors, bats (vampire and insectivorous) and members of the Viverridae (Civet) family may act as Reservoirs (source of disease without necessarily showing apparent symptoms of the disease).
Dogs remain the principal vectors in Africa, Asia, Latin America and parts of Europe and continue to represent the principal source of bite wounds or contact infection in man. Other carnivorous vectors are wolves, jackals, foxes, mongooses, coyotes, skunks, badgers, cats and other members of feline family. Foxes are the principal vectors and as in Canada, Cattle are the principal receptors.
In North America skunks are the common vectors. Rabies occurs in most contries in African continent, but the reported incidence is surprisingly low for an area with such a high population of wild carnivores.
Rabies is not of major economic importance in farm animals, although individual herds and flocks may suffer many fatalities. The disease is always fatal. The prime importantce of rabies is its transmissibility to humans. Although, it may be possible for any type of animal to transmit rabies, infection is seldom due to bites inflicted by solipeds and ruminants. Birds are susceptible to rabies and there is at least one case of clinically diagnosed rabies in boy after bitten by a goose.
Rabies occurs in most countries of the world except in some islands. Australia and New Zealand have claimed non–existence of rabies. Britain, Hawwaii, and Scandinavian are currently claimed free from the disease. Britain had two minor out breaks in dogs involving one dog each year of 1969 and 1970 but the disease was controlled successfully. There is no report of occurrence of rabies from Indian islands.
Rabies is responsible for significant morbidity and mortality in India. The disease is endemic in the country, human and animal cases of rabies are reported from all over the country throughout the year except for Andaman & Nicobar and Lakshadweep Islands. In India, about 96% of the morbidity and mortality due to Rabies is associated with dog bites. Although, Rabies affects people of all age groups, children are the most vulnerable which constitutes 40% of the people exposed to dog bites in Rabies-endemic areas. As per WHO estimates, India accounts for 36% of the global and 65% of the human Rabies deaths in the Southeast Asia region.
(To be contd)