Smallpox
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Transcript of Smallpox
SMALLPOX
MADE BY MD.FADI SAAD AOLOW
INTRODUCTION
A highly contagious and frequently fatal viral disease.
The disease is also known by the Latin names Variola or Variola Vera, which is a derivative of the
Latin Varius, meaning "spotted", or Varus, meaning "pimple".
The term "Smallpox" was first used in Europe in the 15th century to distinguish Variola from the
"great pox" (Syphilis).
Smallpox was responsible for an estimated 300–500 million deaths during the 20th century.
Believed to have begun in Africa and spread to India and china.
U.S.S.R. Weaponized.
Routine vaccination in U.S. ceased in 1972.
HISTORYFirst appeared in northeastern Africa around 10,000 BC
Skin lesions on mummies 1570-1085 BC Ramses V
In the elephant war in Mecca 568 AD, smallpox decimated the Ethiopian soldiers
Introduction of smallpox into the new world (Carribean 1507, Mexico 1520, Peru 1524, and brazil 1555 ) facilitated Spanish conquest
Smallpox destroys Hottentots (1713)
In 1738, smallpox killed half the Cherokee Indian population
Smallpox disrupted colonial army in 1776
Early written description of smallpox India 400 AD
MICROBIOLOGYCaused by Variola virus
Belongs to the genus Orthopoxvirus, the family Poxviridae and subfamily Chordopoxvirinae
Single, linear, double-stranded DNA molecules and replicate in cell cytoplasm.
Shaped like bricks and measure about 300 x 200 nm
in size
Incubation: 12-14 days (range 7-17d)
2 clinical forms:
Variola major
Variola minor
MICROBIOLOGY Variola major
Classic smallpox
Predominant form in Asian epidemics
Highest mortality (~30%)
Variola minor Causes milder disease Discovered in 20th century Started in S. Africa Was most predominant form in N. America
TYPES Classic smallpox was considered the most communicable disease; about
30% of unvaccinated people who came in contact with the virus were infected.
The Hermorrhagic variety of Variola had a much higher death rate (95%)
than classic smallpox and lead to death more quickly.
The Malignant or flat forms of smallpox affected 6% of the population and
evolved slower than the classic type of smallpox but with a death rate of almost 100%.
The Modified variety of Variola essentially affected people who were
vaccinated.
PATHOPHYSIOLOGY
Virus lands on respiratory/oral mucosa
Macrophages carry to regional nodes
Invades Reticuloendothelial organs
White blood cells infected
Systemic inflammatory response
Signs & Symptoms
The initial symptoms that the person has are fever 1030, body aches, headache, chills and vomiting.
After the initial symptoms the virus creates a rash that starts as macules (flat, red lesions) on the skin. Then vesicles (raised blisters) form and lastly pustules (pus filled blisters) appear.
Just after the rash appears, the virus is highly contagious as it moves into the mucous membrane.
Rash Stages Of Development
Rash Stages Of Development
TRANSMISSIONAirborne route Initially via aerosol Then person-to-person Hospital outbreaks
from coughing patients Highly infectious
Infectious materials:SalivaVesicular fluidScabsUrineConjunctival fluidPossibly blood
The virus can cross the placenta, but the incidence of congenital smallpox is relatively low.
Smallpox transmission does not occur through animals or insects.
PREVENTION
• The smallpox vaccine is the only known way to prevent smallpox in an exposed person. The smallpox vaccine helps the body develop immunity to smallpox.
• Isolation of patients if they develop fever.
CONTROL STRATEGIES
Smallpox hospitals (Japan 982 AD).
Variolation 10th century.
Quarantine 1650s.
Home isolation of smallpox in Virginia 1667.
Inoculation and isolation (Haygarth 1793).
Jenner and widespread practice of vaccination throughout Europe and rest of the world.
Mass vaccination.
Surveillance containment.
EPIDEMIOLOGYSmallpox reached Europe between the 5th and 7th centuries
According to one estimate smallpox was claiming 400,000 European lives a year by the end of the 18th century – at a time when the population of the continent numbered less than 200 million.”In the last decade of the 18th century, life expectancy was 32 in France and 40.5 in Denmark. Assuming an average life expectancy of 35 means that of the 200 million people 5.7 million died per year. This means that smallpox was the cause of death of 7% of Europeans at that time
TREATMENTNo proven treatment.
Only thing done was to give them intravenous fluids and medicine to control fever and pain.
Antibiotics, given to prevent possible bacterial infections.
VACCINATIONEdward Jenner demonstrated that immunity
to smallpox could be produced by inoculating a human with material from a lesion on the udder of a cow. Jenner called this infectious material vaccine, and the procedure came to be called vaccination.
The material Jenner used for his vaccine probably contained cowpox virus, a virus related to Variola but not as virulent.
VACCINATIONSmallpox (vaccinia) vaccine dryvax® Lyophilized vaccinia
containing calf lymph. Trace amounts of
antibiotics: Polymyxin B. Streptomycin. Chlortetracycline. Neomycin.
1796 edward jenner develops vaccine
1805 use of cows to produce vaccine
1940s freeze-drying technology
1965 licensure of bifurcated needle
1972 routine vaccination stopped in u.S.
1983 vaccine removed from civilian market
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