|History teachers used to teach that North America had
originally been occupied by one million Indians. That
low number helped justify the white conquest of what could
then be viewed as an almost empty continent. However archeological
research excavations and descriptions left by the first
European explorers suggest an initial number of around
20 million. In the century or two following Columbus's
arrival in the New World, the Indian population is estimated
to have declined by about 95% !
Part of the reason for this quick and overwhelming conquest
goes back to the invaders' technological advantages. Europeans's
guns and steel swords were more effective weapons than
Native American stone axes and wooden clubs.
Only Europeans had ships capable of crossing
the ocean and horses that could provide a decisive advantage
But that is not the whole answer. Far more Native Americans
died in bed than on the battlefield -the victim of germs,
not of guns and swords. Those germs undermined Indian resistance
by killing most Indians and their leaders and by demoralizing
The Indians had never been exposed to European germs and had
neither immunologic nor genetic resistance to them. Smallpox
,measles , influenza , and typhus competed for top among killers.
Pertussis, plague, tuberculosis, diphtheria, mumps, malaria,
and yellow fever came close behind.
And while over a dozen major infectious diseases of Old World
origin became established in the New World, strangely enough,
not a single major killer reached Europe from the Americas
!(The sole possible exception is syphilis, whose area origin
still remains controversial.)
The reason behind this one sidedness appears if we know that
crowd disease evolved from diseases of domesticated herd animals.
There were many such animals in Eurasia. But there were only
five animals that became domesticated in the Americas: the
turkey , the guinea pig, the llama, the duck and the dog.
And these few domesticated animals were unlikely sources of
The importance of animal-derived diseases for human history
extends far beyond the Americas. Eurasian germs played a key
role in decimating native peoples in many other parts of the
world as well, including the Pacific Islands, Australia and
Some definitions -
Infectious disease: Disease caused by
microorganism, such as bacteria, viruses, or protozoa.
Malaria: Infectious disease characterized
by recurring attacks of chill and fever, caused
by the bite of an anopheles mosquito infected
with any of certain protozoans. The name "malaria"
means "bad air" from the belief that
the disease was caused by the unwholesome air
in swampy districts.
Plague: Infectious disease transmitted
to man by the bite of the rat flea. Epidemics
of "the Black Death" swept through Europe
during the 1300s.
Influenza: There are three families of
influenza viruses called the A, B and C viruses.
The A viruses cause the great influenza epidemics,
and the B viruses causes smaller localized
outbreaks the C virus are not important
causes of disease in human being. The A viruses
are not a stable family group. That is why vaccines
are useless against it.