Chapter 9: Smallpox, the Spotted Plague
•Hernan Cortes and his troops set out to explore and claim Mexico for
their king, Charles V.
•Cortes’s ally in the defeat of the Aztec’s was smallpox. But small pox
was present long before their arrival.
•In 1520, an expedition led by Panfilo de Narvaez, had a smallpox-
infected slave among his crew. This initial infection, spread
throughout the Yucatan.
•Smallpox was a selective disease–only the Aztecs died.
•Smallpox was an Old World disease, where the New World
Amerindians had never been exposed and had no immunity.
•Smallpox is indiscriminate.
A Look Back
•Suspected the infectious agent was from a pox-like disease from
domesticated animals, in agricultural settlements of Asia or Africa,
some time after 10,000 BC.
•Best evidence of smallpox in humans is in three Egyptian mummies
from 1570 to 1085 BC. One of these being Pharaoh Ramses V. The
mummies show pockmarks, which are craterlike scars.
•From origins in Africa and India, smallpox spread from the west to
China, first appearing about 200 BC.
•Was known in Greece and Rome but was not a threat until about AD
•Epidemic started in Mesopotamia and soldiers brought it home to Italy.
It raged for 15 years.
•Records of smallpox in the Korean peninsula from ad 583.
•Reached Japan by AD 585.
•In the western part of Eurasia, spread of smallpox occurred in the 8th
and 9th centuries during the Islamic expansion across North Africa and
into Spain and Portugal.
•The Huns were infected in either Persia or India.
•In the 5th century when the Huns descended into Europe, they may
have carried smallpox with them, but it may have already been
established in France and Italy.
•By AD 1000 smallpox was probably endemic in densely populated parts
of Eurasia, from Spain to Japan, as well as African countries bordering
the Mediterranean Sea.
•Moved people to and from Asia Minor during the Crusades in the 12th
and 13th centuries helped reintroduce smallpox to Europe.
•1300 England and Germany suffered epidemics.
•In 16th century it was established in all of Europe except for Russia.
•The English settlers, who arrived in the American colonies in 1617, set
off an epidemic making room for other settlers who came from
Plymouth in 1620.
•In the war of 1763, between England and France for the control of
North America, the British intentionally gave blankets contaminated
with scabs from smallpox to the Indians, and led the tribes to move far
•Smallpox was first introduced into South Africa, by a ship docked in
Capetown in 1713, which carried contaminated bed linen from a ship
returning from India. Smallpox was reintroduced once from a ship
from Srilanka in 1755, and again from Denmark 1767.
•First outbreak in the Americas was among African slaves on the island
of Hisponiola in 1518.
The Disease of Smallpox
•Caused of smallpox is a large virus, which can be seen with the light
microscope. But detailed structure requires an electron microscope.
The outer surface called capsid resembles a diamond and its inner
dumbbell-shaped core contains a double-stranded DNA.
•It has about 200 genes, 35 believed to be involved in virulence.
•Other poxviruses that can infect humans are: monkeypox, cowpox,
milker’s node, tanapox, and chicken pox.
•Enters body via droplet infection by inhalation. Can also be acquired
via direct contact or through contaminated fomites such as clothing.
•The infectious material from the pustules can remain infectious for
•The virus multiplies in the mucous membranes of the mouth and nose.
•During first week of infection there is no sign of illness, but it can still
•Virus moves on to the lymph nodes and then to the internal organs via
the blood stream and multiples again.
•The virus reenters the bloodstream, and around the ninth day the first
symptoms appear: headache, fever, convulsions–quite ill.
•A few days later rash appears.
•Richard Preston in The Demon in the Freezer describes smallpox.
•The individual is infectious a day before the rash appears and until all
the scabs have fallen off.
•Many die a few days or week after the appearance.
Chapter 9: smallpox, the spotted plague: hernan cortes and his troops set out to explore and claim mexico for their king, charles v, cortes"s ally in the defeat of the aztec"s was smallpox. But small pox was present long before their arrival. In 1520, an expedition led by panfilo de narvaez, had a smallpox- infected slave among his crew. This initial infection, spread throughout the yucatan: smallpox was a selective disease only the aztecs died, smallpox was an old world disease, where the new world. Amerindians had never been exposed and had no immunity: smallpox is indiscriminate. One of these being pharaoh ramses v. the mummies show pockmarks, which are craterlike scars: from origins in africa and india, smallpox spread from the west to. China, first appearing about 200 bc: was known in greece and rome but was not a threat until about ad. 100: epidemic started in mesopotamia and soldiers brought it home to i taly.