Microbiology and Immunology

WORLD OF MICROBIOLOGY & IMMUNOLOGY

ix

•

Introduction

potentially deadly agents. Also, lifestyles change and new

opportunities arise for deadly agents. For example, the use of

vaginal tampons by women has resulted in an environment in

which the Staphylococcus bacterium can grow and produce a

toxin causing toxic shock syndrome. New diseases can also

emerge because some agents have the ability to change abrupt-

ly and thereby gain the opportunity to infect new hosts. It is

possible that one of the agents that causes AIDS arose from a

virus that at one time could only infect other animals.

Not only are new diseases appearing but many infectious

diseases that were on the wane in the U.S. have started to

increase again. One reason for this resurgence is that thou-

sands of U.S. citizens and foreign visitors enter the country

daily. About one in five visitors now come from a country

where diseases such as malaria, cholera, plague, and yellow

fever still exist. In developed countries these diseases have

been largely eliminated through sanitation, vaccination, and

quarantine. Ironically, another reason why certain diseases are

on the rise is the very success of past vaccination programs:

because many childhood diseases (including measles, mumps,

whooping cough, and diphtheria) have been effectively con-

trolled in both developed and developing countries, some par-

ents now opt not to vaccinate their children. Thus if the disease

suddenly appears, many more children are susceptible.

A third reason for the rise of infectious diseases is that the

increasing use of medications that prolong the life of the eld-

erly, and of treatments that lower the disease resistance of

patients, generally weaken the ability of the immune system to

fight diseases. People infected with human immunodeficiency

virus (HIV), the virus responsible for AIDS, are a high-risk

group for infections that their immune systems would normal-

ly resist. For this reason, tuberculosis (TB) has increased in the

U.S. and worldwide. Nearly half the world’s population is

infected with the bacterium causing TB, though for most peo-

ple the infection is inactive. However, many thousands of new

cases of TB are reported in the U.S. alone, primarily among

the elderly, minority groups, and people infected with HIV.

Furthermore, the organism causing these new cases of TB is

resistant to the antibiotics that were once effective in treating

the disease. This phenomenon is the result of the uncontrolled

overuse of antibiotics over the last 70 years.

Until a few years ago, it seemed possible that the terrible

loss of life associated with the plagues of the Middle Ages or

with the pandemic influenza outbreak of 1918 and 1919 would

never recur. However, the emergence of AIDS dramatizes the

fact that microorganisms can still cause serious, incurable,

life-threatening diseases. With respect to disease control, there

is still much microbiological research to be done, especially in

relation to the fields of immunology and chemotherapy.

Recent advances in laboratory equipment and techniques

have allowed rapid progress in the articulation and under-

standing of the human immune system and of the elegance of

the immune response. In addition, rapidly developing knowl-

edge of the human genome offers hope for treatments designed

to effectively fight disease and debilitation both by directly

attacking the causative pathogens, and by strengthening the

body’s own immune response.

Because information in immunology often moves rapidly

from the laboratory to the clinical setting, it is increasingly

important that scientifically literate citizens—those able to

participate in making critical decisions regarding their own

health care—hold a fundamental understanding of the essen-

tial concepts in both microbiology and immunology.

Alas, as if the challenges of nature were not sufficient, the

evolution of political realities in the last half of the twentieth

century clearly points toward the probability that, within the

first half of the twenty-first century, biological weapons will

surpass nuclear and chemical weapons as a threat to civiliza-

tion. Accordingly, informed public policy debates on issues of

biological warfare and bioterrorism can only take place when

there is a fundamental understanding of the science underpin-

ning competing arguments.

The editors hope that World of Microbiology and

Immunologyinspires a new generation of scientists who will

join in the exciting worlds of microbiological and immuno-

logical research. It is also our modest wish that this book pro-

vide valuable information to students and readers regarding

topics that play an increasingly prominent role in our civic

debates, and an increasingly urgent part of our everyday lives.

K. Lee Lerner & Brenda Wilmoth Lerner, editors

St. Remy, France

June 2002

Editor’s note: World of Microbiology and Immunologyis

not intended to be a guide to personal medical treatment or

emergency procedures. Readers desiring information related

to personal issues should always consult with their physician.

The editors respectfully suggest and recommend that readers

desiring current information related to emergency protocols—

especially with regard to issues and incidents related to bioter-

rorism—consult the United States Centers for Disease Control

and Prevention (CDC) website at http://www.cdc.gov/.

How to Use the Book

The articles in the book are meant to be understandable

by anyone with a curiosity about topics in microbiology or

immunology. Cross-references to related articles, definitions,

and biographies in this collection are indicated by bold-faced

type, and these cross-references will help explain and expand

the individual entries. Although far from containing a compre-

hensive collection of topics related to genetics, World of

Microbiology and Immunologycarries specifically selected

topical entries that directly impact topics in microbiology and

immunology. For those readers interested in genetics, the edi-

tors recommend Gale’s World of Geneticsas an accompanying

reference. For those readers interested in additional informa-

tion regarding the human immune system, the editors recom-

mend Gale’s World of Anatomy and Physiology.

This first edition of World of Microbiology and

Immunologyhas been designed with ready reference in mind:

• Entries are arranged alphabetically rather than
  chronologically or by scientific field. In addition to clas-
  sical topics, World of Microbiology and Immunology
  contains many articles addressing the impact of

womi_fm 5/6/03 1:34 PM Page ix