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Rabies
Rabies has also been in the news more than ever in the past few years. The virus accounts
for more than 55,000 human deaths annually worldwide, more than polio, diphtheria and
yellow fever combined. Fortunately, rabies in humans is rare in the US. There are usually
only one or two cases per year, with bats being the primary source. The first reported case
of rabies transmitted by bats occurred in 1953. Among the 19 naturally acquired cases in
the US from 1997–2006, 17 were associated with bats.7
History of Rabies
Rabies (derived from the Sanskrit, “to do violence”) may be the oldest documented
human disease. Ancient writers in Mesopotamia, China, Greece, Rome and India
described classic symptoms that have both intrigued physicians and terrified the pub-
lic for millennia.8 In 1546, an Italian physician, Girolamo Fracastoro, provided a classic
description of the symptoms, noting that: “The patient can neither stand nor lie down, like
a mad man he flings himself hither and thither, tears his flesh with his hands, and feels
intolerable thirst. This is the most distressing symptom, for he so shrinks from water and
all liquids that would rather die than drink or be brought near to water. It is then they bite
other persons, foam at the mouth, their eyes look twisted, and finally they are exhausted
and painfully breathe their last.”9
During the early part of the 19th century, German and French workers proved by
experimentation that saliva from rabid animals and dogs was infective for healthy dogs.
This confirmed the centuries-old suspicion that the causative agent of rabies was associ-
ated with the saliva of a rabid animal. Perhaps the most famous of all medical experiments
involved the early use of rabies vaccine in human cases by Louis Pasteur. He capitalized
on earlier work in which the infectious agent in rabies was transmitted from rabid dogs to
rabbits.
Pasteur and his collaborators conceived of a process of attenuating the agent by
repeated passages through rabbits. Strips of fresh spinal cord material were taken from
rabbits that had died from rabies and were exposed to dry, sterile air for various lengths
of time. This tissue was ground up and suspended in a sterilized broth. This solution was
used as a vaccine and tested only on dogs until 6 July 1885. On that date, Pasteur first
administered the vaccine to a nine-year-old patient with severe wounds from the bites of a
mad dog, almost certainly fatal. He was treated with 13 separate injections over an 11-day
period and survived.10 However, it was not until 1936, when Drs. Webster and Clow first
grew the virus in tissue culture, that any real advances were made.11 Nerve- and brain
tissue-derived vaccines were eventually developed.
A human rabies vaccine is now available from a number of manufacturers that
induces an active immune response in approximately seven to 10 days. Rabies Immune
Globulin can also be used to provide a rapid passive immunity to anyone who has not
been previously vaccinated.12
The Organism
Rabies is caused by a number of different strains of the large, bullet-shaped, single-
stranded RNA viruses of the genus Lyssavirus, family Rhabdoviridae. Lyssavirus includes
seven genotypes: rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, European
bat lyssaviruses 1 and 2 and the newly discovered Australian bat lyssavirus. Almost all
human cases are caused by genotype 1. DNA patterns of isolates from skunks, raccoons,
foxes and various bats are distinguishable from each other using the reverse transcriptase
polymerase chain reaction (RT-PCR) technique.13 Isolates from human cases can now be
identified to determine the likely animal source, aiding in epidemiologic investigations.
Natural reservoirs of rabies in the US are raccoons, skunks, bats and foxes. It is com-
forting to know that rabies is well controlled in the US through vaccination of domestic
Bats, Rabies and Vampires
Rabies
Rabies has also been in the news more than ever in the past few years. The virus accounts
for more than 55,000 human deaths annually worldwide, more than polio, diphtheria and
yellow fever combined. Fortunately, rabies in humans is rare in the US. There are usually
only one or two cases per year, with bats being the primary source. The first reported case
of rabies transmitted by bats occurred in 1953. Among the 19 naturally acquired cases in
the US from 1997–2006, 17 were associated with bats.7
History of Rabies
Rabies (derived from the Sanskrit, “to do violence”) may be the oldest documented
human disease. Ancient writers in Mesopotamia, China, Greece, Rome and India
described classic symptoms that have both intrigued physicians and terrified the pub-
lic for millennia.8 In 1546, an Italian physician, Girolamo Fracastoro, provided a classic
description of the symptoms, noting that: “The patient can neither stand nor lie down, like
a mad man he flings himself hither and thither, tears his flesh with his hands, and feels
intolerable thirst. This is the most distressing symptom, for he so shrinks from water and
all liquids that would rather die than drink or be brought near to water. It is then they bite
other persons, foam at the mouth, their eyes look twisted, and finally they are exhausted
and painfully breathe their last.”9
During the early part of the 19th century, German and French workers proved by
experimentation that saliva from rabid animals and dogs was infective for healthy dogs.
This confirmed the centuries-old suspicion that the causative agent of rabies was associ-
ated with the saliva of a rabid animal. Perhaps the most famous of all medical experiments
involved the early use of rabies vaccine in human cases by Louis Pasteur. He capitalized
on earlier work in which the infectious agent in rabies was transmitted from rabid dogs to
rabbits.
Pasteur and his collaborators conceived of a process of attenuating the agent by
repeated passages through rabbits. Strips of fresh spinal cord material were taken from
rabbits that had died from rabies and were exposed to dry, sterile air for various lengths
of time. This tissue was ground up and suspended in a sterilized broth. This solution was
used as a vaccine and tested only on dogs until 6 July 1885. On that date, Pasteur first
administered the vaccine to a nine-year-old patient with severe wounds from the bites of a
mad dog, almost certainly fatal. He was treated with 13 separate injections over an 11-day
period and survived.10 However, it was not until 1936, when Drs. Webster and Clow first
grew the virus in tissue culture, that any real advances were made.11 Nerve- and brain
tissue-derived vaccines were eventually developed.
A human rabies vaccine is now available from a number of manufacturers that
induces an active immune response in approximately seven to 10 days. Rabies Immune
Globulin can also be used to provide a rapid passive immunity to anyone who has not
been previously vaccinated.12
The Organism
Rabies is caused by a number of different strains of the large, bullet-shaped, single-
stranded RNA viruses of the genus Lyssavirus, family Rhabdoviridae. Lyssavirus includes
seven genotypes: rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, European
bat lyssaviruses 1 and 2 and the newly discovered Australian bat lyssavirus. Almost all
human cases are caused by genotype 1. DNA patterns of isolates from skunks, raccoons,
foxes and various bats are distinguishable from each other using the reverse transcriptase
polymerase chain reaction (RT-PCR) technique.13 Isolates from human cases can now be
identified to determine the likely animal source, aiding in epidemiologic investigations.
Natural reservoirs of rabies in the US are raccoons, skunks, bats and foxes. It is com-
forting to know that rabies is well controlled in the US through vaccination of domestic
Bats, Rabies and Vampires