Smallpox
is a highly infectious and often fatal viral disease that leaves
permanent pits in the skin. Before smallpox was wiped out, it killed,
disfigured, and blinded millions of people.
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Infectious disease
Viral
Infection
A
Different Kind of War
Beginning
in 1966, the World Health Organization declared war against an enemy
that throughout history had caused governments to fall and wiped out
entire populations. The allies in this battle were mostly ordinary
people in villages and towns, and their main weapon was a vaccine.
Ten years later, they achieved one of the finest victories in the
history of medicine: the global destruction of smallpox. The last
known outbreak of the disease, which killed 2 million people in 1967,
was in Somalia in 1977. In 1980, the World Health Assembly declared
the world free of smallpox. Today people have nothing to fear from
this disease.
Edward
Jenner
Edward
Jenner was born in England in 1749. He worked as a country doctor. In
Europe, it was believed that milkmaids who developed cowpox (a
disease that affects the udders of cows but is harmless to humans)
did not get smallpox. To test this belief, in 1796 Jenner began
inoculating (i-NOK-yoo-layt-ing) people with cowpox virus. In an
experiment that would not be permitted today because it would be
considered too dangerous, he later injected these same people with
smallpox virus. They remained disease-free. Jenner's experiment with
cowpox proved the value of vaccination and led to its widespread use.
Modern immunology, that is, the study of how organisms fight
infection, began with Jenner.
What
Is Smallpox?
Smallpox
is an infection caused by the variola virus. The virus was spread
when one person breathed in droplets from the air that an infected
person had breathed out, for instance by sneezing or coughing. It
could also be spread by simply touching someone with the disease.
What
Causes Smallpox?
Social
factors played a major role in the transmission of smallpox. Because
it spread by face-to-face contact with another person, it thrived in
the crowded conditions of poverty. Smallpox is highly infectious, but
it is not as contagious as measles or the flu. If the virus ran out
of humans to infect, it could not spread. However, the lesions that
appeared on the skin as the disease progressed were infectious and
could contaminate nonliving objects such as clothes or blankets for
long periods. Children, the elderly, and people who were sick from
other diseases would catch smallpox more easily, but the virus could
infect anyone.
What
Are the Symptoms of Smallpox?
Smallpox
would begin very suddenly, and in the beginning it was like a bad
case of the flu. After a few days, the flu-like symptoms went away,
and the skin broke out in bumps. At first the bumps were solid, but
soon they became filled with liquid, like blisters, and then with
pus. Finally, after about 2 weeks, the blisters dried up and formed
scabs. When the scabs fell off, they left permanent pits in the skin,
most often on the face. Many people who developed this form of
smallpox recovered. However, in severe cases, where a high fever and
bleeding rash were present, a person might have died in a few days.
Should
the Smallpox
Virus
Be Destroyed?
As
of 1999, the smallpox virus officially remained only in two
high-security laboratories in Atlanta and Moscow. These "stocks"
of the virus were kept because they have value for scientific
research. But some people argue that they should be destroyed because
the damage the virus would cause if it were ever released would pose
too great a risk. The World Health Organization fixed the date of
June 30,1999, to destroy the remaining stocks of smallpox, but then
changed its mind because of the strong debate in the scientific
community. Scientists argue that a future smallpox epidemic could
occur, and without these stored viruses, newer vaccines and antiviral
drugs could not be made. They say that stored vaccines are old and
deteriorating. Also, the old vaccine is a live virus that could not
be given to people who have impaired immune systems or who have had
organ transplants. The virus itself might be needed to develop
effective vaccines for these people.
How
Did Doctors Diagnose Smallpox?
Before
smallpox was wiped out, it was easy to tell whether people had the
disease simply by their appearance. Sometimes, the initial fever
might have been mistaken for the flu. Or the rash might have been
confused
How
Was Smallpox Treated?
In
the past, treatment for smallpox was aimed at making patients
comfortable and limiting the spread of the disease. If possible,
patients were separated from other people, and the area around them
and the things they touched were kept very clean to prevent further
infection.
Vaccination
Prevents Smallpox
Hundreds
of years ago, in Asia, it was observed that people who survived
smallpox never got it again. This observation led to a practice later
called variolation (var-ee-o-LAY-shun), which involved, for example,
rubbing pus from a smallpox lesion into small scratches or cuts in
the skin of healthy people in the hope of protecting them. Although
these people still developed smallpox, it was often a mild form.
Variolation
was unknown in Europe and North America until the 1700s. In 1796,
Edward Jenner showed that variolation using cowpox instead of
smallpox could protect a person completely from the disease, sparing
the person from even a minor case of smallpox. Jenner's vaccine (from
the Latin word for "cow") made it possible to control
smallpox in many countries. But it was only in 1980 that enough
people around the world had been vaccinated to stop the disease
forever.
In
the past, children were routinely immunized against smallpox before
their first birthday. But now that smallpox has been wiped out,
vaccination is no longer necessary.
What
Are Viruses?
Viruses
are organisms that are smaller than cells, so tiny that they can be
seen only with a special kind of microscope. To multiply and cause
disease, viruses need the help of a living cell. Although viral
particles may be present in large numbers, some viruses can remain in
the body for a long time, even many years, before people begin to
feel sick. The AIDS (acquired immune deficiency syndrome) virus is a
good example of this kind of virus. Other viruses, like influenza or
smallpox, make people ill very quickly.
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