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

Thanks