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What is an Epidemic?
An
epidemic is generally a widespread disease
that affects many individuals in a population. An epidemic may be
restricted to one locale or may even be global (pandemic). An outbreak
of a disease is defined as being epidemic, however, not by how many
members or what proportion of the population it infects but by how fast
it is growing. When each infected individual is infecting more than one
other individual, so that the number of infected individuals is growing
exponentially, the disease is in an epidemic state. Thus even if the
number of people affected is small, the phenomenon may still be called
an epidemic, although for small epidemics the term "outbreak" is more
often used.
Some examples
of historical epidemics include the
Black Death, or bubonic plague, of Mediaeval Europe, the influenza
(flu) epidemic concuring with the end of World War I, and the current
AIDS epidemic.
Every infection is a
race between the microbes and
the host. The microbe, following the indelible rules of evolution,
strives to survive and reproduce, while the host's immune system mounts
a warlike defense designed to find, destroy, and eliminate it. An agent
that kills its host quickly cannot be expected to survive long enough
to reproduce. Thus excessive virulence is not selected for in
evolution. Germs, which can reproduce and be passed from one host to
another, are favored.
The Black Death
The Black Death (also The Bubonic Plague, and
more recently The Black Plague) was a devastating epidemic in Europe in
the 14th century which is estimated to have killed about a third of the population. Most
scientists believe that the Black Death was an outbreak of bubonic
plague, a dreaded disease that has spread in pandemic form several
times through history. The plague is caused by the bacterium Yersinia
pestis which is spread by fleas with the help of animals like the black
rat - what we would call today the sewer rat. Sometimes, the term
"Black Death" is used for all outbreaks of plague and epidemics.
Influenza
...or as it is commonly known, the flu - is
a contagious disease caused by an RNA virus of the orthomyxoviridae
family. The name comes from the old medical belief in unfavourable
astrological influences as the cause of the disease. Influenza's
effects are much more severe and last longer than those of the cold.
Recovery takes about one to two weeks. Influenza can be deadly,
especially for the weak, old or chronically ill. Some flu pandemics
have killed millions of people, for example the "Spanish Flu" pandemic
of 1918–1919, which is believed to have killed more people in total
than World War I.
AIDS
AIDS (the acronym meaning Acquired
Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome, and
occasionally written as Aids) is a human disease characterized by
progressive destruction of the body's immune system. It is believed by
the overwhelming majority of medical opinion to result from infection
with HIV, the Human Immunodeficiency Virus
(which is actually a retrovirus).
AIDS was first
noticed among homosexual men and
needle drug users in the 1980s. By the 1990s the syndrome had become a
global epidemic and in 2004, 58% of those with AIDS were women. While
homosexual men continue to suffer higher per capita AIDS rates, the
majority of victims are currently heterosexual women, men, and children
in developing countries.
AIDS is currently
considered incurable; where
treatments are unavailable (mostly in poorer countries) most sufferers
die within a few years of diagnosis. In the developed countries,
treatment has improved greatly over the past decade, and people have
lived with AIDS for ten to twenty years.
HIV is transmitted
by bodily fluids, such as
blood, semen and vaginal secretions. It causes disease by infecting
CD4+ T cells, a type of leukocyte (white blood cell) that normally
co-ordinates the immune response to infection and cancer. When a
person's CD4+ T cell count decreases sufficiently he or she is prone to
a range of diseases that a healthy person's body is normally able to
fight. These diseases include cancers and opportunistic infections,
which are usually the cause of death in persons with AIDS. HIV also
infects brain cells, causing some neurological disorders.
Smallpox
Smallpox is one of
the most devastating of all
infectious diseases. It is highly infectious, kills 30% of victims and
can spread in any climate or season. It is carried in the air, making
it extremely contagious and able to contaminate many people in a short
time. Smallpox used to ravage the world but following a vaccination
program in 1980 the World Health Organisation (WHO) declared that it
had been eradicated, so countries stopped vaccination. In the same year
Russia started to produce large quantities, successfully adapting it
for use on bombs or missiles. Russia's industry is still capable of
producing vast amounts of smallpox, enough to kill hundreds of
millions. Vaccination ceased in 1972 in the US - everyone born after
that date has no immunity.
Cholera
The
disease proceeds in possibly three stages
(a) Invasion: at the end of the incubation period the symptoms are
malaise, headache, severe diarrhea resulting in the so-called "rice
water stool," (which derives its characteristic whitish color from
intestinal tissue which is exfoliated (shed) and excreted along with
innumerable Vibrios), anorexia, and a slight fever.
This severe
diarrhea can be as high as one liter per hour. The
resulting loss of fluid and the accompanying electrolyte imbalance can
lead to hypovolemic shock, renal failure, and cardiac failure. (b)
Collapse: circulation is almost completely arrested, accelerated
respiration, weak pulse, decreased systolic blood pressure, diminished
or no urine output.
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This stage lasts
from a few hours to one or two
days. The mind remains clear until just before death, when coma occurs.
Death follows shortly thereafter. Death can follow the onset of
symptoms in little as six hours. (c) Reaction: sometimes, even when the
grim reaper is about to claim victory, vomiting ceases, diarrhea
becomes less frequent and less watery, and convalescence follows.
How could they be distributed?
There are many ways
in which they could be
distributed. Russia developed techniques using missiles and bombs to
spread the pathogens. Anthrax was recently deployed using the post. Al
Queda attempted to acquire crop-dusting planes, which could be used to
spread pathogens to millions. They could be released from conventional
planes. Terrorists could release them in ventilation systems to spread
them across a building. However they are spread, infectious pathogens
could soon be passed to others, leading to casualties thousands of
times greater than the original number infected.
Why are they so dangerous?
If any of them were
to be turned into weapons,
there are many reasons they could be potentially more devistating than
nuclear weapons,
- Nuclear and chemical weapons
only kill people
in an isolated area, meaning that large numbers have to be used to kill
most of an enemy's population. Biological
weapons can kill thousands
with a microscopic amount.
- They are virtually undetectable before being
deployed, allowing them to be transported into hostile countries by car
or plane, as well as by missile.
- They cause no damage to buildings, allowing a
country to eliminate its enemies and move in to take control of
undamaged cities.
- They can kill far more people than any other
type of weapon.
- Even if only a few die, they cause terror
within an enemy's population.
- They are extremely cheap compared to other
weapons. A vast arsenal can be grown from one sample. This is
especially beneficial for terrorists.
- They can be acquired with terrifying ease.
Using only a false letterhead and credit card, a man in America was
able to acquire a large amount of Bubonic Plague. He was later found to
be a member of a white supremacist organisation, had he not been caught
another outbreak of plague could have occurred.
This would instill
fear - Slow economies to a
crawl - and cause mass scale panic. Surely you see the dangers involved
in people 'playing god' with these dangerous diseases.
Armageddon
Online
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