Chapter 13
Chapter 13: Preventing Infectious Diseases
Objectives
Learning Objectives
On completing this chapter, you will be able to:
• Describe the step-by-step chain of events by which infectious diseases are transmitted.
• Explain the mechanical defenses that help protect the body from infection.
• Describe how the immune system responds to an invading pathogen.
• Discuss the role of immunizations in preventing infectious diseases.
• Describe the causes and management of common infectious diseases and emerging infections of
concern.
• List and describe practical steps that can help strengthen your immune system and reduce your risk of
contracting an infectious disease.
• Explain how HIV infection affects the body and how it is transmitted, diagnosed, and treated.
• Discuss the symptoms, risks, and treatments for other major STDs.
• List STD prevention strategies.
Terms and Definitions
acquired immunity (AI) – a form of immunity resulting from exposure to foreign protein (most often
wild, weakened, or killed pathogenic organisms).
acute rhinitis – the common cold; the sudden onset of nasal inflammation.
agent – the causal pathogen of a particular disease.
antibodies – chemical compounds produced by the body’s immune system to destroy antigens and their
toxins.
artificially acquired immunity (AAI) – a type of acquired immunity resulting from the body’s response to
pathogens introduced into the body through immunizations.
cell-mediated immunity – immunity provided principally by the immune system’s T cells, both working
alone and in combination with highly specialized B cells; also called T cell-mediated immunity.
chlamydia – the most prevalent sexually transmitted disease; caused by a nongonococcal bacterium.
chronic fatigue syndrome (CFS) – an illness that causes severe exhaustion, fatigue, aches, and depression;
mostly affects women in their 40s and 50s.
epidemic – a highly significant increase in the number of cases of an infectious illness existing in a given
time period in a given geographical area.
human papillomavirus (HPV) – sexually transmitted viruses, some of which are capable of causing
precancerous changes in the cervix; causative agent for genital warts.
humoral immunity – immunity, also called B-cell mediated immunity, that is responsible for the
production of critically important immune system elements known as antibodies.
immune system – the system of cellular and chemical elements that protects the body from pathogens,
abnormal cells, and foreign protein.
Lyme disease – a bacterial infection transmitted by deer ticks.
mononucleosis (“mono”) – a viral infection characterized by weakness, fatigue, swollen glands, sore
throat, and low-grade fever.
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naturally acquired immunity (NAI) – a type of acquired immunity resulting from the body’s response to
naturally occurring pathogens.
pandemic – an epidemic that has crossed national boundaries, thus achieving regional or international
status (HIV/AIDS is a pandemic).
passively acquired immunity (PAI) – a temporary immunity achieved by providing extrinsic antibodies to
a person exposed to a particular pathogen.
pathogen – a disease-causing agent.
pelvic inflammatory disease – an acute or chronic infection of the peritoneum or lining of the
abdominopelvic cavity and fallopian tubes; associated with a variety of symptoms or none at all and a
potential cause of sterility.
peritonitis – inflammation of the peritoneum, or lining of the abdominopelvic cavity.
sexually transmitted diseases (STDs) – infectious diseases that are spread primarily through intimate
sexual contact.
shingles – painful fluid-filled skin eruptions along underlying sensory nerve pathways—caused by
reactivation of once-sequestered herpes zoster (chicken pox) virus.
toxic shock syndrome (TSS) – a potentially fatal condition caused by the proliferation of certain bacteria
in the vagina whose toxins enter the general blood circulation.
urethra – the passageway through which urine leaves the urinary bladder.
virulent – capable of causing disease.
Lecture Outline
I. Infectious Disease Transmission

Infectious diseases can produce epidemics.
A. Pathogens

A pathogen can be a virus, bacterium, or fungus.
B. Chain of Infection

This chain explains how infectious diseases spread.
1.
Agent

2.
Reservoir

3.
This is the disease-causing agent.
In most cases, the reservoir is the body of the person already infected.
Portal of Exit

The typical portals of exit are the digestive system, urinary system, respiratory
system, reproductive system, and blood.
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4.
Mode of Transmission

5.
Two principal methods are direct and indirect transmission.
Portal of Entry

The principal portals of entry are the digestive system, respiratory system, and
reproductive system.
6.
The New Host

Overall health, acquired immunity, health care services, and behavior can affect
the risk of becoming a new host.
C. Stages of Infection

These are the incubation, prodromal, clinical, decline, and recovery stages.
II. Body Defenses: Mechanical and Cellular-Chemical Immune Systems

The body has mechanical and cellular defenses.
A. Divisions of the Immune System

Two groups of cells provide T cell-mediated immunity and humoral immunity.
B. The Immune Response

Various types of white blood cells destroy antigens. Macrophages begin ingesting
antigens as they are encountered.
C. Immunizations

Only 81% of American preschoolers are adequately immunized.
III. Causes and Management of Selected Infectious Diseases
A. Nonsocomial Infections

Spread in conjunction with delivery of health care services. From providers to patients or
from patients to other patients
B. The Common Cold

Can be caused by an array of viruses.
C. Seasonal Influenza

This disease has the potential for more serious complications than the common cold.
D. Avian (Bird) Influenza and Novel H1N1 (Swine) Influenza
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
Widening array of animal hosts.
E. Tuberculosis

F.
People with a damaged immune system are susceptible to TB.
Pneumonia

This term describes a variety of bacterial, viral, fungal, rickettsial, mycoplasmal, and
parasitic respiratory infections.
G. Mononucleosis

This disease sometimes requires a month or two of recuperation.
H. Chronic Fatigue Syndrome

I.
Researchers are seeking the cause or causes.
Bacterial Meningitis

A number of colleges and universities now require immunization against this disease
before students are admitted.
J.
Lyme Disease

Bacterial infection from deer ticks
K. Hantavirus Pulmonary Syndrome

This potentially fatal disease has been reported in most of the western states and some
eastern states.
L. West Nile Virus

This disease is spread by mosquito bites and has been reported in six eastern states.
M. Tampon-Related Toxic Shock Syndrome

Super absorbent tampons left in the vagina for longer than 5 hours can cause this
potentially fatal disease.
N. Hepatitis

Inflammatory process in the liver cause by hepatitis Type A, B, C, D or E
O. AIDS

AIDS has killed more than 583,000 Americans.
1.
Cause of AIDS
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
2.
The HIV virus attacks the helper T cells of the immune system.
Spread of HIV

The percentage of women who were infected through heterosexual contact has
increased to 72 percent.
3.
Diagnosis of HIV Infection

Diagnosed through a clinical examination, laboratory tests for accompanying
infections, and an initial screening test.
4.
The Course of HIV Infection

Primary symptoms disappear within a few weeks and are typically mistaken for
another illness.
5.
Treatment of HIV Infection

No treatment currently exists to cure HIV infection, though drugs are available
to help reduce the level of HIV in the body and improve chances for survival.
6.
Drug Resistance in HIV Infection

7.
HIV has the ability to develop drug resistance during the course of treatment.
HIV/AIDS on the World Stage

The “Aids Crisis” is prevalent in Africa, the Indian subcontinent, and areas of
Asia and Latin America.
8.
Prevention of HIV Infection

People can take preventative steps to limit their chance of infection.
VI. Sexually Transmitted Diseases

By age 25, about one third of adults will have contracted an STD.
A. Chlamydia (Nonspecific Urethritis)

This is thought to be the most prevalent STD in the United States today.
B. Human Papillomavirus

One should use condoms to limit the risk of contracting HPV.
C. Gonorrhea

The incidence of gonorrhea rose 18 percent between 1997 and 2001.
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D. Herpes Simplex

Herpes rivals chlamydia as the most prevalent STD.
E. Syphilis

F.
Syphilis is a serious disease that, left untreated, can cause death.
Pubic Lice

Those infected must treat themselves, their clothing, their sheets, and their furniture.
G. Vaginal Infections

Three common pathogens are the yeast or fungus pathogen Candida (monilia) albicans,
bacterial vaginosis, and the protozoan Trichomonas vaginalis.
H. Cystitis and Urethritis

I.
These usually can be treated with an antibiotic.
Sexually Transmitted Diseases, Health, Role Fulfillment, and a Sense of Well-Being
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Supplemental Resources: Activities, Assignments, and
Discussion Material
For your convenience listed below are some of the available supplemental assets for this chapter. For the
most up-to-date supplement information, please refer to the textbook website
(http://www.mhhe.com/payne11e).
Online Learning Center
Personal Assessments
What is Your Risk of Contracting a Sexually Transmitted Disease? *
Test Your Knowledge of Infectious Diseases
Infectious Disease Risks
*also found in the text
Web Activities
Anatomy of an Epidemic: A Quiz
Health Curriculum Quiz – causes and cures of infections disease
Infectious Disease Quiz
Web Dental Office
HerpeSite
Focus On
The Changing Picture of Infectious Disease
HealthQuest CD-ROM
Communicable Diseases Unit
Wellness Activities: STDs: Are You At Risk?
Virtual Date Exploration
Activities
Core Textbook Activities: Talking Points
1.
Through community service work, you meet a couple that say that they have not had their children
immunized and don’t see the reason for doing so. How would you explain the importance of having
this done? (p. 360)
2.
In a job interview with a representative from a large pharmaceutical company, you are asked about
your feelings regarding the affordability of HIV/AIDS medications in third world countries. What
would your response be? (p. 375)
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Individual Activities
1.
Investigate your immunization record and determine what childhood diseases you have had. Compile a
list of diseases for which you have not been vaccinated and that you have not contracted and consult a
physician about the need for immunizations. This list should be kept up-to-date.
2.
Investigate one of the infectious diseases described in this chapter on a more detailed basis. This may
be done by researching the disease in current health journals and writing a summary of that research.
3.
Interview various health professionals (e.g., nurses, physicians) who come into contact with people
with various infectious diseases. Areas that might be covered in such an interview include the means of
protecting against the contraction of the disease by the health practitioner, what is done if the health
practitioner refuses to treat someone with an infectious disease (e.g., the person with AIDS), and how a
person is treated if the disease is as yet unidentified.
4.
Write a brief history of the development of specific vaccines currently in use to prevent the spread of
specific diseases. Such vaccines might include polio, measles, mumps, and rubella.
Community Activities
1.
Assist with community-wide immunization programs such as influenza vaccines for the elderly by
helping with registration, working on publicity, or performing other tasks as needed.
2.
Visit a laboratory where tests are performed for syphilis and gonorrhea. Have the technician explain
how the culture is taken, the length of time needed, and what to look for in the culture.
3.
Compile a list of places where testing for STDs can be performed in the campus area. Be sure to
include the following information: name, address, telephone number, cost, whether an appointment is
required, and whether treatment can be provided.
4.
Develop an HIV/AIDS Awareness Day on your campus. AIDS Quilt panels are available from local
and national AIDS groups. Quilt panels add a very personal touch to a campus AIDS awareness week.
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