14.1: Chapter Introduction

Last updated
Save as PDF

Page ID: 25511

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Our species no longer suffers large predators as so many species do (Figure 13.0.1). But dangerous predators remain part of the human condition. We call them diseases.

By analogy, think of visible organisms living in a pond— from birds, fish, frogs, insects, and plankton to aquatic plants (Figure \(\PageIndex{1}\), left). To be successful across a region, the organisms must gain resources in the pond while competing with other species, survive predators, and enable their offspring to disperse to another pond. To be successful they must not destroy the pond in which they live, at least until they or their offspring have dispersed to another pond.

What is the body of a plant or animal to an infectious virus or bacterium? It is like a pond. There may be other pathogens in the body competing for its metabolic resources. There are predators in the body in the form of an immune system. And to be successful the pathogen must disperse to another body without destroying the body in which it lives, at least until it or its offspring has orchestrated a way to disperse into and colonize another body.