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Dakota Shirar
Professor Polando
Essay 3
3 November 2013
Deadly Bites
Over time, many diseases have infected the world. Some have been so deadly that
they plague the world and wipe out a fraction of the population; others are so rare that
scientists are still uncertain about them. It is very hard to learn about these viruses,
prions, bacteria, and other microorganisms before they cause damage to the world. Even
once they have made an appearance it is still difficult to find an absolute cause or cure.
One specific disease that has been known for a long time but still is not completely
understood is rabies. The name came from the Latin word rabere meaning rage. It is a
virus that causes damage to the central nervous system. There have been many cases in
different animals, most commonly dogs but also bats, raccoons, coyotes, and skunks.
This virus has used animals to spread to humans, resulting in a gloomy demise. Since the
discovery and investigation, some facts have been discovered and progress has been
made. Biologists have done all they can to rid the disease but to no avail. Rabies is a viral
disease with a long history that dates back to 500 BC and is fatal to 100% of those who
go without treatment of a vaccine.
The best way to learn about a disease is to look at the history. The first recorded
case was of a canine reported by Democritus in 500 BC (Scholand). Soon after, the
Greeks recognize two special rabies gods, “one to prevent rabies and one to heal”
(Scholand). In the early years of AD, there was an outbreak across the Roman Empire,
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Greece, and Crete. Over the next hundreds of years, many outbreaks occur, slowly taking
over the planet. The first human case being in Germany in 1271 where 30 people died,
then in Spain, and the rest of Europe before coming to the Americas in 1700, North
America specifically in 1785 near Rhode Island (Scholand). The website RabiesFree.org
provides a clear time line with specific cases of out-breaks with a location and year.
During this time dogs all over the world are being shot for rewards and killed in the street
while other animal species are being wiped out by this virus. Many countries were afraid
of an outbreak and spared no animals. In 1800, hundreds of dead foxes are found in
France. The virus killed all foxes in the area. Finally, after hundreds of years and many
deaths, in 1881, Louie Pasteur and his partner Emile Roux begin the search for a possible
cure. Before, however, the only cure was to attempt to suck out all the “poison” from the
wound before cauterizing hoping that the virus in the saliva of the animal would be
drained of the wound (Scholand). But of course it did not work. “In 1885, Pasteur
provides a vaccine and tests it on a man who was mauled by a rabid dog, which is
successful making Pasteur a hero” (Scholand). To find a cure, the cause has to be known.
In the early history, like many other treacherous diseases, the cause of rabies was
unclear. Simply, rabies is caused by a virus that is shaped like a rod or bullet in the
Lyssavirus family. To be more specific it is a “single-stranded, negative-sense,
unsegmented, enveloped RNA virus… that encodes 5 proteins” (Rupprecht). In order to
multiply, the virus enters a cell then is transcribed and translated into viral proteins. This
is where it becomes copied and sent throughout the body. It is also important to know
how the virus is introduced to the hosts. This starts from a long chain of animal-to-animal
transmission eventually leading to human infection. All mammals are susceptible to
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rabies but only a few are important carriers being: dogs, coyotes, foxes, cats, skunks,
raccoons, and bats. The most common way for the virus to make the jump between
animal and human is though salivary contact. When a person is bitten and the skin breaks
that is the most dangerous, but not the only mode of transmission. Scratches, contact with
mucous membranes, or aerosol transmission are rare but will also spread the disease
(CDC). Sometime the meat on farms can be diseased and then eaten by humans causing
infection. Dogs or larger carriers will bite cattle and farmers will send the animal for
butchering without noticing the disease. When the animal is eaten the human receives the
virus. One cases of human-to-human contamination were transplants of infected corneas
between eight people (Krebs). After years of research, the cause has been determined.
When dealing with rabies, early detection is difficult but very important like many
other illnesses. Signs and symptoms in humans may be hard to recognize but should be
known. The incubation period of rabies can greatly vary from 10 days to 6 years. The
virus can penetrate the peripheral nervous system or lay dormant before attacking the
central nervous system (Rupprecht). Normally the symptoms show within 30 days. There
are three phases of the disease (“Rabies”). The first is the Prodromal Phase where the
symptoms are light and resemble many possible diseases. Early signs can be similar to
the flu such as fever, headache, sore throat, and general weakness. Pain, itching, or
burning feeling around the wound may appear later (CDC). They increase in intensity and
start to attack more specifically. As the disease progresses, more symptoms appear like
shallow breathing, increased heart rate, dilated pupils, difficulty swallowing, hyper
salivation, hydrophobia, overactive facial expressions, spasms, increased muscle tone,
and eventually paralysis (Krebs). Mental status may change causing disorientation,
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hallucinations, confusion, sensitivity to light and sound, anxiety, melancholia, agitation,
and aggression (Krebs). The next phase is Excitation, which attacks the musculature and
nerves. Symptoms appear as weakness of facial muscles and eyes. The eyes can swell,
cannot follow motion, be controlled, or dilate irregularly due to ocular muscle
dysfunction. The final phase is Paralytic. This is where symptoms lighten but paralysis
sets in progressing into a coma followed by death (“Rabies”). “Once clinical signs of
rabies appear, the disease is nearly always fatal, and treatment is typically supportive”
(CDC). Once symptoms emerge, death will follow with in a week if untreated. There is
hope of treatment if caught soon enough.
Barriers have been put in place to prevent infection. The public is advised to stay
away from wild animals. Also, vaccinations are given to pets to prevent the transmission
from wildlife to domestic animals and then to humans. “One of the most exciting
developments in recent decades is the demonstration that wildlife can be vaccinated
against rabies” (Krebs). These vaccines were introduced to red foxes in Canada and as a
result the incidences of rabies decreased. Rabies is the only disease where vaccination
after exposure is effective. This treatment is only necessary if there is “true” exposure,
meaning an animal bite or scratch that penetrates the skin, most importantly the face and
hands. Contact such as petting or contact with blood, urine, or feces are not considered
dangerous exposures. Usually after a bite, the animal is contained and monitored for 10
days to see if it shows signs of rabies and the person receives an immediate vaccine
(Krebs). If there is no indication of rabies, the animal is released and treatment of the bite
victim is discontinued. If there are signs of rabies, the animal is quickly killed and the
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brain is tested while the bite victim continues treatment. The only way the treatment will
be effective is if the virus is caught early enough.
With a virus this deadly, knowledge and prevention are important. Many people
and animals died from the virus before a cause was ever known. Many breakthroughs
have been made so more people will avoid the disease and live. However, this disease
will never be eradicated. There have been vaccines made for humans in case of a bite as
well as preventative shots for house pets so they do not transfer the virus, but since wild
animal can carry as well, the vaccination may never reach that group. It has been well
advised to take caution when dealing with wild animals and some are more present than
others. Many studies have tested the most predominate animal carrier in different areas of
the globe. In North America, raccoons, foxes, skunks, and bats host the rabies virus. In
Europe, the red fox is the main reservoirs while in Eurasia, the raccoon dog and gray wolf
are carriers. Each region is home to a different animal that carries rabies (Krebs).
Although all animals should be considered risky some mammals are less likely to carry.
These animals include rats, mice, squirrels, other rodents, rabbits, or hares (Krebs). It is
necessary to know the signs and when to seek medical care. Catching the virus before
signs present themselves is the important so that the vaccine can work at its best. History
has shown that rabies is a very dangerous virus that causes much mayhem in the human
and animal populations.
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Bibliography
Krebs, John W., Mark L. Wilson, and James E. Childs. "Rabies: Epidemiology,
Prevention, and Future Research." Journal of Mammalogy 76.3 (Aug. 1995): 68194. Print.
"Rabies." Centers for Disease Control and Prevention. Centers for Disease Control and
Prevention, 15 Feb. 2012. Web. 13 Nov. 2013.
"Rabies." Rabies. N.p., 30 Nov. 1999. Web. 13 Nov. 2013.
Rupprecht, Chrales E. "Rhabdoviruses: Rabies Virus." NCBI. U.S. National Library of
Medicine, n.d. Web. 13 Nov. 2013.
Scholand, Stephen. "A Rabies-Free World, Inc. - History." A Rabies-Free World, Inc. History. Rabies Free World, Inc., n.d. Web. 13 Nov. 2013.