Family:
Subfamily:
Genus:
Species:
Subspecies:
Related Species:
Related Genera:
mallpox Family Tree
Poxviridae
Chordopoxvirinae
Orthopoxvirus variola major and minor vaccinia cowpox monkeypox ectromelia camelpox taterapox raccoonpox
Uasin Gishu
Avipoxvirus
Capripoxvirus
Leporipoxvirus
Parapoxvirus
Suipoxvirus
Tanapox
Molluscum contagiosum

-large, complex virus
-“brick-shaped” particle
-linear double-stranded DNA
-disk-shaped core
-double membrane
-lipoprotein envelope
-replicates in cytoplasm
single, stable serotype

-transmitted by respiratory aerosol, direct contact with lesions, contact via fomites
-virus enters upper respiratory tract, causes primary viremia
-then infects internal organs, causes secondary viremia
-spreads to skin; rash is caused by viral replication
-incubation period of 7-14 days from infection to symptoms

-prodrome of fever and malaise
-skin rash proceeding from macules to papules to vesicles to pustules to crusts over the course of
2-3 weeks
-lifelong immunity, though vaccination confers ~10 years immunity

A less virulent form of the variola virus existed.
Its existence may have hindered the eradication process, because people were less likely to be concerned about a more minor disease and were, therefore, less likely to report an infection.
This woman continued her normal daily activities throughout her illness.

Variola major: ~20-50% depending on population
Variola minor: 1%
There were several clinical forms of smallpox identified: usual, discrete, confluent, hemorrhagic, flat, and probably more.
Both the subtype of smallpox and individual and population variation would affect mortality rates.

2000-1000 BC: possible smallpox in
Egyptian mummies
This is the mummy of
Ramses V, who died in
1157 BC. Note the eruptions on the lower face. Also note skin folds possibly due to swelling.

~100 BC: probable mention in Susruta Samhita in India
Spread to Middle East, Far East, and Europe

48-49: introduced into China from the southwest
450: Bishop Nicaise of Rheims recovers from smallpox
622: smallpox described by Ahrun of Alexandria
583: spread from China to Korea
585: spread from Korea to Japan
700s: Arabs carry to Spain
900s: Arabs carry to western Africa
Al-Razi describes smallpox
Chinese intranasal variolation
Japanese describe “red treatment”
1000-
1100: spread by Crusaders

1200s: cutaneous variolation by Mamelukes in Egypt introduction of smallpox to Iceland from Denmark
1438: major Paris epidemic
1507: introduction to Caribbean
1520: to Mexico
1524: to Peru
1555: to Brazil
1617: epidemic in Massachusetts
1623: first account in Russia
1630: Siberia
1713: South Africa; destruction of Hottentots
1724: variolation in Siberia
1744: variolation in Japan
1776: Quebec; next year Washington variolates continental army
1789: Australian aborigines

1600s: nasal variolation regularly practiced in China
This Chinese drawing portrays insufflation of powdered smallpox scabs.

Spread of Smallpox During Colonialization

1798: Edward Jenner describes vaccination
1800s: Native American pandemics
1802: vaccination in India
1805: in India
1840: in Siam
1849: in Japan
1845: systematic production of vaccine in cows, Negri in Naples
1863: President Lincoln develops smallpox
1890s: Variola minor described in South Africa
1896: Variola minor in Florida; spreads through US in 4 years

1863: Abraham Lincoln contracted smallpox
This portrait was taken eleven days before the
Gettysburg Address. Lincoln developed smallpox just hours after the Address, so this photograph may have been taken on the day he was initially infected.

1798: Edward Jenner describes vaccination
Edward Jenner (1749-1823)
A pastel portrait by J.R.Smith
from 1800 cleverly portrays
Jenner with a cow and milkmaid in the background.

-born May 17, 1749
-third son of Reverend Stephen Jenner
-apprenticed to an apothecary at age 13
-private house-student of John Hunter in 1770
-studied angina pectoris, cuckoos, manure, ophthalmology, bird migration, tuberculosis
-violinist, poet, artist
-apparently became interested in vaccination when told by a country girl that she was immune from smallpox because she’d had cowpox
-vaccinated an 8 year old boy, James Phipps, in 1796 with material from a presumed cowpox lesion on the hand of Sarah Nelmes
-found that those vaccinated were resistant both to variolation and to smallpox infection

1801: Jenner prophesizes the eventual eradication of smallpox

Variolation caused a more severe skin eruption, but one much less severe than full-blown smallpox.
Vaccination generally caused a single pustule at the site of inoculation.

Male
Female
1795
23
27
1817-31
38
41
This effect is presumed to be primarily due to the introduction of vaccination. Vaccination was the only major public health program implemented during the first part of the nineteenth century.

1914: epidemic in Russia due to WWI
1951: eliminated from North America, Central America
1953: eliminated from Europe
1950s: eliminated from Mediterranean Africa
1955: 8thWorld Health Assembly rejects concept of eradication as unrealistic
1959: at urging of Viktor Zhdanov, 12th WHA undertakes global eradication of smallpox
1960s: eliminated from China
1966: Intensified Smallpox Eradication Programme

Smallpox:
1. has a single stable serotype
2. has no animal reservoir
3. causes a prompt antibody response
4. is easily recognized clinically
5. does not cause subclinical infections or carrier states

-mass vaccination programs
-surveillance with outbreak containment
-reward programs for identifying cases
-smallpox recognition cards and pamphlets
-development of heat stable vaccines total expenditure of $97,969,737 from 1967 to 1979

WHO smallpox identification card, shown to people to help them identify local cases of smallpox.
1966: intensification of efforts to wipe out smallpox, despite widespread discreditation of the concept of eradication
(Failures to eradicate yellow fever and malaria left doubts regarding the possibility of ultimate success.)

1975: eradication from Asia
Rahima Banu, who had the world’s last case of naturally occurring
Variola major (Bangladesh)

1977: eradication of smallpox from the entire world
Ali Maow Maalin, who had the world’s last case of naturally occurring smallpox
(Somalia)

But…
August 27,1978, Birmingham, England
Janet Parker, a 40 year old medical photographer, developed electron microscopically proven smallpox, probably through an air duct connected to the smallpox laboratory at the
University of Birmingham. She died of renal failure associated with her illness.
Her father died on September 5 of a myocardial infarction.
The professor who ran the microbiology laboratory committed suicide and died on September 7.
Her mother developed a mild case of smallpox on September 8, recovered and was released from quarantine on September 22.
This latter was the last known case of smallpox in the world.

We, the members of the global commission for certification of smallpox eradication, certify that smallpox has been eradicated from the world.
Geneva
December 9, 1979
Official parchment certifying global eradication

-wildlife reservoir
-material stored by variolators
-laboratory stocks
-secret stocks for possible biological warfare
-reactivation of latent virus
-preservation on scabs, clothing, gravesites
-transformation of another species of orthopoxvirus
All are generally viewed as highly unlikely.

As of 1988, two laboratories were known to have variola virus stocks:
Moscow Research Institute for Viral Preparations
Centers for Disease Control, Atlanta

Baxby, Derrick. Jenner’s Smallpox Vaccine: The Riddle of
Vaccinia Virus and its Origin. Heinemann Educational
Books, London, 1981.
Fenner, F. et al. Smallpox and its Eradication. World Health
Organization, Geneva, 1988.
Hopkins, Donald. Princes and Peasants: Smallpox in History.
University of Chicago Press, Chicago, 1983.
Jenner, Edward. The Causes and Effects of the Variolae Vaccinae.
Sampson Low, London, 1798 (privately reprinted for the
Classics of Medicine Library, 1978).
Levinson, Warren and Jawetz, Ernest. Medical Microbiology and Immunology. Appleton and Lange, Norwalk,
Connecticut, 1994.
Shurkin, Joel. The Invisible Fire: The Story of Mankind’s Victory
Over the Ancient Scourge of Smallpox. G.P. Putnam,
New York, 1979.