The Birth and Death of Smallpox

Abstract

Since the beginning of human existence, the evolution of disease
has closely followed the evolution of culture. A complex feedback relationship
exists between humans and the pathogenic organisms in their
environment. Disease has been a powerful selective force, acting on
human biology as well as culture. By the same token, human behaviors
have been selective agents in disease evolution because cultural practices
influence exposure to and transmission of all infectious diseases.
Smallpox is an excellent example of these interactions for several
reasons. Its related high mortality rate imposes selection pressure on
human biology, Its effect on culture and history is virtually immeasurable,
The role of smallpox in decimating American Indian populations
during conquest is one example of this effect (McNeill, 1976:209). Because
smallpox is a uniquely human disease, the variola virus is viable
only in the human organism, making it very sensitive to characteristics
of human biology and behavior. Finally, its eradication graphically illustrates
the power of human practices to be selective agents in the
evolution of disease.