297
ll living creatures share two basic objectives in life:
survival and reproduction. This doctrine applies
equally to bacteria, viruses, fungi, and protozoa. To
satisfy these goals, organisms must extract from the
environment essential nutrients for growth and prolif-
eration; for countless microscopic organisms, that envi-
ronment includes the human body.
The content in this chapter has been divided into four
parts: (1) general concepts of infectious diseases, (2) epi-
demiology of infectious diseases, (3) general principles
of diagnosis and treatment, and (4) new and emerging
infectious diseases.
General Concepts of Infectious
Diseases
Normally, the contact between humans and microor-
ganisms is incidental and, in certain situations, may
actually benefit both organisms. Under extraordinary
circumstances, however, the invasion of the human body
by microorganisms can produce harmful and potentially
lethal consequences. The consequences of these inva-
sions are collectively called
infectious diseases
.
Terminology
All scientific disciplines evolve with a distinct vocabu-
lary, and the study of infectious diseases is no exception.
The most appropriate way to approach this subject is
14
C h a p t e r
General Concepts of Infectious Diseases
Terminology
Agents of Infectious Disease
Prions
Viruses
Bacteria
Rickettsiaceae, Anaplasmataceae,
Chlamydiaceae, and Coxiella
Fungi
Parasites
Epidemiology of Infectious Diseases
Mechanisms of Transmission
Portal of Entry
Source
Mechanisms of Disease Production
Toxins
Adhesion Factors
Evasion Factors
Invasion Factors
Clinical Presentation
Site of Infection
Disease Course
Diagnosis of Infectious Diseases
Culture
Serology
Protein Detection
DNA and RNA Detection
DNA Sequencing
Treatment of Infectious Diseases
Antibacterial Agents
Antiviral Agents
Antifungal Agents
Surgical Interventions
New and Emerging Infectious Diseases
Global Infectious Diseases
Mechanisms
of Infectious
Disease
A
U N I T
4
Infection and
Immunity
