Transcript Smallpox - HCC Learning Web

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The name of
presentation????
Smallpox is a very contagious disease that caused
by either of two a virus variants, Variola major
and Variola minor, that include severe rash and
pimple like all over the body. Smallpox are
localizes in small blood vessels of the skin and
in the mouth and throat.
The pimple like rash will
Soon be fill with fluid blisters.
Variola – this is Latin
name, so it must be
written everywhere in
Italic
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The origin of smallpox is uncertain, but it is believed to have
originated in Africa and then spread to India and China thousands
of years ago.
The first recorded smallpox epidemic was in 1350 BC during the
Egyptian-Hittite war.
It is estimated that Smallpox reached Europe between the 5th and
7th centuries and present in major European cities by the 18th
century.
Epidemics occurred in the North American colonies in the 17th and
18th centuries
The disease killed an estimated of 400,000 Europeans each year
during the 18th century, and was responsible for a third of all
blindness.
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About 20–60%, and over 80% of infected children died from the
disease.
During the 20th century, it is estimated that smallpox caused
300–500 million deaths.
In the early 1950s an estimated 50 million cases of smallpox
occurred in the world each year.
In 1967, the World Health Organization (WHO) estimated that
15 million people contracted smallpox and that 2 million died in
that year.
WHO certified the eradication of smallpox in December 1979.
After successful vaccination campaigns throughout the 19th and
20th centuries
To this day, smallpox is the only human infectious disease to
have been completely eradicated.
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Mozart and Beethoven
contracted and survived
the disease as children;
both had visible
pockmark scars on their
faces. Both George
Washington and
Abraham Lincoln,
Presidents of the United
States, contracted and
recovered from the
disease.
While other people in China with smallpox die, only
Emperor Kangxi survived and took over China in
1661. Emperor Kangxi was born in May, 4, 1654 –
December, 20, 1722. In China, the Qing Dynasty
Kangxi was promoted to the throne ahead of his
older brother, because he had survived the disease,
when his older brothers who had not yet had it.
Like Date Masamune also was connected by smallpox
that attacked his eye and would have killed him,
but he gouged out his own eye. Which he is now
know as the “one eyed dragon”.
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Variola virus infects
only humans. The virus
can be easily
transmitted from person
to person via the air.
Inhalation of only a few
virus particles is
sufficient to establish an
infection. Transmission
of the virus is also
possible if items such as
contaminated linen are
handled
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Transmission of smallpox occurs
through inhalation of airborne
variola virus, usually droplets
expressed from the oral, nasal, of an
infected person.
It is transmitted from one person to
another primarily through
prolonged face-to-face contact with
an infected person, usually within a
distance of 6 feet, but can also be
spread through direct contact with
infected bodily fluids or
contaminated objects such as
bedding or clothing
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Rarely, smallpox has been spread by
virus carried in the air in enclosed
settings such as buildings, buses,
and trains. Smallpox is not notably
infectious in the prodromal period
and viral shedding is usually
delayed until the appearance of the
rash, which is often accompanied by
lesions in the mouth and pharynx.
The virus can be transmitted
throughout the course of the illness,
but is most frequent during the first
week of the rash, when most of the
skin lesions are intact. Infectivity
wanes in 7 to 10 days when scabs
form over the lesions, but the
infected person is contagious until
the last smallpox scab falls off.[
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Smallpox is highly contagious, but generally spreads
more slowly and less widely than some other viral
diseases, perhaps because transmission requires close
contact and occurs after the onset of the rash. The
overall rate of infection is also affected by the short
duration of the infectious stage. In temperate areas, the
number of smallpox infections were highest during the
winter and spring. In tropical areas, seasonal variation
was less evident and the disease was present
throughout the year. Age distribution of smallpox
infections depends on acquired immunity. Vaccination
immunity declines over time and is probably lost in all
but the most recently vaccinated populations. Smallpox
is not known to be transmitted by insects or animals
and there is no asymptomatic carrier state.
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Preliminary symptoms are a brief rash on the upper body,
followed by general malaise, fever, muscle stiffness, vomiting,
headache, backache with delirium occurring in about 15% of cases.
Two to three days after this, rashes develop on the mucous
membranes (enanthema) and on the skin (exanthema) affecting
the face, hands, and forearms. Secretions from the enanthema
include infectious virus and play a key role in secondary
transmission of the virus. However, the most infective period
appears to be before the development of the rash.
The rash spreads across the body and the lesions enlarge and fuse
to form (pus-filled) vesicles. The development of the lesions is
remarkably synchronized throughout the course of the disease.
The pustules eventually scab about two weeks after the onset of
symptoms.
In typical cases of smallpox (variola major) mortality is about 3%
in vaccinated populations and 30% in unvaccinated ones. The
disease can take on several other forms including black or
hemorrhagic smallpox that have higher mortality rates
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A photograph of the trunk of
a young smallpox victim
taken in Bangladesh in 1973.
The photograph shows
several important features:
The size and shape of the
pocks;
the pocks all show about the
same stage of development,
synchronous development is
a key feature;
The relative lack of pocks on
the trunk and lower
abdomen.
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Initial diagnosis of smallpox is likely based on a history and
physical examination findings.
Some ways that doctors go about diagnosing smallpox are:
• The doctor may take a throat swab to make the diagnosis of
smallpox.
• The doctor may take a sample from a freshly opened pustule.
• The doctor may take sample fluid from a spinal tap (lumbar
puncture) if he or she suspect cases of hemorrhagic smallpox.
• Under certain conditions,
cytoplasmic inclusion bodies
(also known as Guarnieri bodies)
may be visible within the cells.
There are three ways of diagnosing Smallpox from the sample collected:
Viral Cultures:
An electron microscope is used to identify the virus in infected fluid on
material
scraped from skin lesions
Polymerase Chain Reaction (PCR):
Is a technique to amplify a single or few copies of a piece of DNA across
several
orders of magnitude, generating thousands to millions of copies of a particular
DNA sequence. The method relies on thermal cycling, consisting of cycles of
repeated heating and cooling of the reaction for DNA melting and enzymatic
replication of the DNA.
Can be divided into 3 steps:
1.
Exponential amplification: At every cycle, the amount of product is
doubled (assuming 100% reaction efficiency). The reaction is very
sensitive: only minute quantities of DNA need to be present.
2.
Leveling off stage: The reaction slows as the DNA polymerase loses
activity and as consumption of reagents such as dNTPs and primers
causes them to become limiting.
3.
Plateau: No more product accumulates due to exhaustion of reagents and
enzyme
Enzyme-linked Immunosorbent Assay (ELISA):
This is a rapid immunochemical test that involves an enzyme (a protein
That catalyzes a biochemical reaction). It also involves an antibody or
Antigen (immunologic molecules).
It is unclear,
HOW smallpox is
being diagnosed
by PCR method.
You gave the
description of the
very method, but
not diagnosing.
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The Smallpox Expectations (Prognosis )
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Smallpox is one of the most contagious of all infectious diseases.
Studies have shown that about 30% of people exposed to the virus
can become infected.
Death from smallpox ranged as high as 35 % of those who were
infected.
Smallpox has been eliminated as a human disease. But the virus has
not
Survivors of the disease may experience severe complications:
 Deeply scarred skin
 Blindness
 Arthritis
 Osteomyelitis (bone infection)
 Fetal infections during pregnancy resulting in additional severe
complications or death of the fetus
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The realization that survivors of smallpox were
immune for the rest of their lives led to the process
of variolation.
Variolation- deliberate exposure of a mild form of
smallpox to a healthy person to induce immunity,
practiced to avoid more severe forms of the
outbreak
First practiced by Buddhist nun from 1022-1063
who would grind smallpox scabs into a powder
then blow them into the nose of a nun-immune
person
2% of people variolated with smallpox actually
died
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Edward Jenner later discovered milkmaids
with cowpox, a less deadly disease, never
developed smallpox.
He inoculated eight-year old James Phipps
with the weak cowpox. After Phipps recovered
Jenner again tried to infect him with smallpox,
but found the boy developed no symptoms.
Jenner coined the word “vaccine” and his work
was soon adopted. By 1800, about 100,000 had
been vaccinated worldwide.
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A more modern
vaccine, Dryvax, was
manufactured from a
weak virus named
New York City Board
of Health strain and
licensed by the FDA.
Last outbreak
occurred in Texas in
1949.
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In 1967, the World
Health Organization
(WHO) launched a
worldwide campaign
to eradicate smallpox.
Last case in Somalia in 1977
On May 8, 1980 WHO declared the world
free of smallpox due to massive
vaccination efforts
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United States stopped vaccination the
population in 1972, but continued to vaccinate
military personnel until 1990.
Forms of the virus are being safeguarded at the
Centers for Disease Control in Georgia and also
Russia for anti-bio-weaponry research in case
some form of smallpox emerges in the future.
1. Too small fonts. They are supposed to
be at least 22pts.
2. There are no any references
(textbook(s), websites, etc.); did you
do all these investigations/discoveries
yourselves?! Where from did you get
all pictures??
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