SMALLPOX

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SMALLPOX

• Stevan Cordas DO MPH
• Clinical Assistant Professor UNTHSC

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History

• First indicated in Egypt 1500 BC.
• Rameses V died of smallpox in 1154 BC.
• China first recorded 4th century AD.
• 622 AD Ahrun of Alexandria first describes
  smallpox.
• India 7th century AD.

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History

• Early 16th century smallpox epidemics in
  Africa.
• 1507 introduced into the Caribbean.
• 1520 to 1555 introduced into Mexico and south
  America.
• 1617 severe outbreak in Massachusetts.
• 1763 used against Indians by Amherst.

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History

• 1721 Boston cotton Mather obtained services of
  Zabeil Boylston. 285 patients inoculated. 6 died.
  (2) of 5579 cases not inoculated 844 died (about
  15). Smallpox lesions were utilized.
  Variolation.
• 1774 Benjamin Jesty, a farmer, introduced cowpox
  vaccination. Never given credit.
• 1794 Edward Jenner legitimized and refined cowpox
  vaccination for smallpox immunization. Vacca
  means cow in Latin.

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History

• 1777 Washington orders variolation of American
  army.
• Early 19th century pandemics among Indians.
• 1870 last great epidemic in Europe.
• 1947 last case in US.
• 1977 last case in the world -Somalia.

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Last known case of smallpox
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U.S. Smallpox HospitalMinton House, Cape
Girardeau, Missouri
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The virus

• Orthopoxvirus include smallpox, monkeypox,
  rabbitpox, camelpox, cowpox, and other animal pox
  viruses, all of which cross react serologically.
  Large DNA virus.
• Pox viruses enter the respiratory tree mucosa and
  produce a brief viremia followed by a latent
  period of 4 to 14 days. The incubation period of
  smallpox is 7 to 17 days with 10-12 days the mean.

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The prodrome

• Smallpox prodrome occurs abruptly and lasts 2 to
  3 days. It produces headaches, fever often 102º
  or more, prostration, and backache. Infection and
  enanthema of the pharynx and tongue occur
  initially. This precedes the appearance of dermal
  rash by one day.

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The Rash

• The epithelial capillary bed is invaded and a
  characteristic rash appears. The kidney, spleen,
  lymph nodes, liver bone marrow and other organs
  become heavily infected.
• The rash at first is macular then in one or two
  days, 2 to 3 mm papules form.

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The Rash

• In another 2 or 3 days 3 to 5 mm vesicles form.
  They first occur on the face and extremities and
  affect the palm and soles (centrifugal
  distribution). Lesions in a region appear the
  same age.
• Between 4 and 7 days after the rash appears,
  pustules are present which last 5 to 8 days.
  Umbilication and crusting then occur.

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Types of smallpox

• Ordinary (Variola major) three subtypes. About 30
  mortality.
• Confluent confluent rash on the face and
  forearms.
• Semiconfluent Confluency only on face, discrete
  otherwise.
• Discrete areas of normal skin between the
  lesions, even on the face.
• Rao 1972

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Types of smallpox

• Variola sine eruptione fever without rash
  must be confirmed serologically.
• Flat type lesions remain flat and confluent.
  Usually fatal. 3-5 of cases
• Hemorrhagic type early with purpuric rash
  always fatal. Late bleeding into the pustules
  usually fatal. 5-7 of cases

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Differential Diagnosis -Varicella

• Varicella usually in children less than 10.
• No significant prodrome.
• Starts on trunk and doesnt affect palms or
  soles.
• Different appearances of lesions in a given
  region of the body.
• Rapid progression to vesicles in 24 hours.
• Not morbidly ill.
• Lesions not hard, fragile.

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Varicella lesions
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Other diseases in differential

• Impetigo
• Herpes Zoster disseminated
• Stevens Johnson syndrome
• Drug eruptions
• Bullous Pemphigoid
• Molluscum contagiosum
• Secondary syphilis
• Disseminated herpes simplex
• Foot and mouth disease

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Mulloscum Contagiosum
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Laboratory testing

• Direct fluorescent antibody
• Indirect fluorescent antibody
• Electron microscopy
• Polymerase chain reaction
• Serologic studies
• Culture
• 3 specimens from each person

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Treatment of febrile vesicular eruption

• Isolate immediately Airborn and contact
  precautions.
• Divide into high risk, moderate risk and low risk
  of having Variola. Check CDC site.
• Contact health department and infectious disease
  specialist.
• Supportive care and testing per support
  (response) team.
• Vaccinia immune globulin and cidofovir.

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Vaccination

• Effective up to 72 hours after the prodrome
  symptoms start. Not after the rash starts.
• It is a live virus of vaccinia (similar to
  cowpox) so site must be covered and taken care of
  until scab falls off.

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Vaccine

• Vaccine is 95 effective.
• Lasts for 3 to 5 years then wanes. Revaccination
  lasts longer.
• Vaccine is given on upper arm with bifucated
  needle.
• If vaccine successful red itchy bump forms in
  about 3 days. In first week a large blister
  appears. Then scab forms and falls off the third
  week.

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Complications of vaccine

• If exposed to smallpox the risks of smallpox out
  way the risks of the vaccine. About 14 to 52 per
  million vaccinated will get serious side effects
  and about 1 to 2 out of a million will die as a
  result of the vaccine.
• Most suffer from low grade fever, flu-like
  symptoms and sore arm.

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Complications of vaccine

• About a thousand out of a million will get more
  serious problems such as spreading the vaccinia
  from the local site to a distant site. It can
  cause blindness if it gets in the eye.
• Bloodborn (generalized vaccinia)
• Erythema multiforme at site of lesion
• Encephalitis

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Eczema Vaccinatum CDC
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Autovaccination CDC
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Fatal Vaccinia Necrosum CDC
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Do not give vaccine to the following

• Children under 12 months.
• Pregnant women
• Do not give to children under age 18 except under
  emergency conditions. - Advisory Committee on
  Immunization Practices.
• Immune depressed individuals.(HIV etc.)
• Those with eczema or certain skin conditions.
• If you are living with such patients except under
  emergency conditions.

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Major criteria of Smallpox

• Febrile prodrome 1 to 4 days before rash occurs
  with fever (they all have a fever), fatigue,
  headache, backache, perhaps vomiting, abdominal
  pain.
• Rash follows which is firm, hard, deep. May be
  confluent or umbilicated
• Lesions all in the same stage of development.

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Minor criteria

• Centrifugal distribution with greatest
  concentration on face and extremities.
• Patient appears morbid
• First lesions in mouth, face and extremities
• Lesions on soles and palms
• Slow development of lesions.

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Local Public Health Departments

• Tarrant county - 1800 university drive. Fort
  worth Texas 817871-8828
• Dallas county 2377 north Stemmons freeway
  Dallas Texas 214-819-2004

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