Download 13 Protecting Against Infectious and Noninfectious

Chapter 13 Lecture
Health: The Basics
Tenth Edition
Protecting Against
Infectious and
Noninfectious Diseases
OBJECTIVES
• Explain how your immune system works to protect you, and what
you can do to boost its effectiveness.
• Discuss actions that you can take to protect yourself from common
infectious diseases.
• Describe the most common pathogens that infect humans and the
diseases caused by each.
• Explain the major emerging and resurgent diseases affecting
national and international populations; discuss why they are
increasing in incidence and what actions are being taken to reduce
risks.
• Discuss antimicrobial resistance, why it occurs, and what we can do
to reduce the prevalence of resistant pathogens.
• Discuss the various sexually transmitted infections, their means of
transmission, and actions that can be taken to prevent their spread.
• Discuss human immunodeficiency virus (HIV) and acquired
immunodeficiency syndrome (AIDS), trends in infection, treatment,
and prevention, and the impact of HIV/AIDS on special populations.
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The Process of Infection
• Disease-causing agents called pathogens are
found in air and food and on nearly every object
or person.
• An epidemic is a disease outbreak that affects
many people in a community or region at the
same time.
• A pandemic is a global epidemic of a disease.
• When a pathogen is virulent, it is strong enough
to overcome host resistance and cause disease.
• One becomes immunocompromised when the
immune system is impaired.
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Routes of Transmission
• Direct contact – kissing or touching an infected
person
• Indirect contact – touching something that the
infected person has touched
• You may also autoinoculate yourself by
transmitting a pathogen from one part of your
body to another.
• Animal-borne (zoonotic) infections are spread by
domestic and wild animals.
• Interspecies transmission is rare but does occur.
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Risk Factors You Can Control
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Stress
Nutrition
Fitness level
Sleep
Drug use
Personal hygiene
High-risk behaviors
Exposure to products and services that
increase risk
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Risk Factors You Typically Cannot Control
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Heredity
Aging
Environmental conditions
Organism virulence and resistance
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The Body's Defenses against DiseaseCausing Pathogens
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Your Body's Defenses against Infection
• Physical and Chemical Defenses
– Skin
– Enzymes in body secretions
– Internal linings of the body
– Immune system defenses
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How the Immune System Works
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Immunity
Antigens
Antibodies
Humoral immune response
Cell-mediated immunity
– Lymphocytes
• B lymphocytes
• C lymphocytes
– Macrophages
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The Cell-Mediated Immune Response
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Your Body's Defenses against Infection
• Autoimmune Diseases
– Sometimes the body makes a mistake and targets its
own tissues.
– Common autoimmune disorders are rheumatoid
arthritis, systemic lupus erythematosus (SLE), Type 1
diabetes, celiac disease, and multiple sclerosis.
• Inflammatory Response, Pain, and Fever
– Four cardinal signs of inflammation: redness,
swelling, pain, and heat
– Fever is another indicator of inflammation.
• High temperatures can destroy some disease-causing
organisms.
• Stimulates more white blood cell production.
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Vaccines: Bolstering Your Immunity
• Vaccines consist of killed or weakened versions
of the disease-causing microorganism or an
antigen that is similar to but less dangerous than
the disease antigen.
• There are three different types of immunity:
– Artificially acquired active immunity - Given orally or
by injection
– Naturally acquired active immunity - Obtained by
exposure to antigens in the normal course of daily life
– Naturally acquired passive immunity - Occurs when a
mother passes immunity to her fetus via shared blood
supply or breast milk
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Allergies
• An allergy occurs as part of the body's attempt
to defend itself against a specific antigen or
allergen.
– Production of antibodies
– Hypersensitive reaction
– Release of histamines
• Hay Fever
– "Pollen allergy"
– Most prevalent when ragweed and flowers are
blooming
– Sneezing and itchy, watery eyes and nose
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Bacteria
• Bacteria are single-celled organisms.
– Diseases caused by bacteria can be treated with antibiotics.
• Staphylococcal infections
– Methicillin-resistant Staphylococcus aureus (MRSA)
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Streptococcal infections
Meningitis
Pneumonia
Tuberculosis (TB)
– Multidrug-resistant TB (MDR-TB)
– Extensively drug-resistant TB (XDR-TB)
• Tick-borne bacterial diseases
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ABC News Video: Attack of the Superbug
Discussion Questions
1. Why is MRSA so difficult to treat?
2. What can be done to keep yourself and
your family safe from MRSA?
3. What are symptoms of MRSA infection?
4. What is the greatest fear of treating
MRSA?
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Examples of Five Major Types of Pathogens
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Viruses
• Viruses are the smallest known pathogens.
– Consist of a protein structure that contains either ribonucleic acid
(RNA) or deoxyribonucleic acid (DNA).
– Incapable of carrying out any life processes on their own; to
reproduce must invade and inject their own RNA or DNA into a
host cell.
– Diagnosis can be difficult because some viruses have incubation
periods (the time from infection to symptoms) that can last years.
– Drugs powerful enough to kill viruses generally kill the host cells.
• The common cold
• Influenza
• Hepatitis: three different types
– A (HAV)
– B (HBV)
– C (HCV)
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Other Pathogens
• Fungi
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Candidiasis
Ringworm
Jock Itch
Toenail fungus
• Protozoans
– Trichomoniasis
– Giardiasis
• Parasitic worms
– Pinworms to large tapeworms
• Prions
– Bovine spongiform encephalopathy (BSE – mad cow disease)
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Emerging and Resurgent Diseases
• West Nile Virus
– In 2010 there were nearly 1,000 cases of West Nile
virus in the United States.
• Avian (Bird) Flu
– The virus has yet to mutate into a form highly
infectious to humans.
• Escherichia coli O157:H7
– Produces a lethal toxin and can cause severe illness
or death.
– Eating rare or undercooked ground beef, drinking
unpasteurized milk or juice, or swimming in sewagecontaminated water or public pools can cause
infection via ingestion of fecal matter.
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Sexually Transmitted Infections (STIs)
• More than 20 known types of sexually
transmitted infections (STIs)
• In the United States you have a one in two
chance of getting an STI by age 25.
• Only some are curable.
• What's Your Risk?
– Moral and social stigma can keep infected
people from seeking treatment.
– Casual attitude toward sex
– Ignorance about infections/symptoms
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Continuum of Disease Risk for Various
Sexual Behaviors
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Routes of Transmission
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Sexual intercourse
Oral–genital contact
Hand–genital contact
Anal
Mouth-to-mouth contact
Contact with fluids from body sores
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Chlamydia
• In the United States, 2.8 million are infected annually.
• Many people display no symptoms.
• Secondary damage can lead to injury to the prostate
gland, seminal vesicles, and bulbourethral glands, and
arthritis-like symptoms in men.
• Secondary damage to the cervix, or fallopian tubes, can
cause sterility and lead to pelvic inflammatory disease in
women.
• Chlamydia may be responsible for one type of
conjunctivitis, an eye infection.
• If detected early, it is easily treatable with antibiotics.
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Gonorrhea
• Gonorrhea is one of the most common STIs in the
United States.
• Symptoms in men are white, milky discharge and painful
urination.
• Most women do not experience symptoms, though
occasionally experience vaginal discharge and a burning
sensation while urinating.
• Complications if not treated include scarring and sterility.
• If detected early, it is easily treatable with antibiotics.
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Syphilis
• Syphilis is caused by a bacterial organism
• Known as the "great imitator" as symptoms often
resemble other STIs.
– Sometimes there are no symptoms.
• Four stages of syphilis
– Primary – chancre develops and then disappears in 3-6 weeks.
– Secondary – a rash or white patches appear on the skin or
mucous membranes.
– Latent – invades the organs and causes lesions called gummas.
– Tertiary/late – heart and central nervous system damage, along
with loss of senses and motor ability.
• Easily treated with antibiotics except in the late stage.
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Syphilis
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Herpes
• The herpes family of diseases is not transmitted
exclusively by sexual contact.
• Infection begins with burning sensation and redness at
site and then turns into a blister full of the virus.
– In blistering stage, there is the possibility to spread the virus
through autoinoculation.
– If left undisturbed, the site will clear and the virus will go
dormant, but can reoccur during periods throughout life.
• Herpes can be spread from mother to child during birth.
• There is no cure for herpes, but there are drugs that can
treat symptoms and reduce viral shedding.
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Herpes
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Human Papillomavirus (HPV) and Genital
Warts
• Over 100 different types of HPV
– People infected with low-risk HPV may
develop genital warts.
• Complications
– Dysplasia—change in cells that may lead to
a precancerous condition
• HPV vaccination
– Recommended for girls and women aged 9 to
26
– Gardasil also licensed safe and effective for
males aged 9-26
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Genital Warts
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Other Sexually Transmitted Infections
• Candidiasis (Moniliasis) or yeast infection
– Caused by a yeast-like fungus
– Symptoms include severe itching, burning, and swelling.
– Antifungal drugs can cure candidiasis in just a few days.
• Trichomoniasis
– Caused by a protozoan
– Symptoms in women include an unpleasant-smelling discharge
accompanied by a burning sensation, itching, and painful
urination.
– Most men do not experience symptoms.
– Usually transmitted by sexual contact or toilet seats, wet towels,
or other items with discharged fluids on them.
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Pubic Lice
• Informally called "crabs."
• Symptoms include itchiness in the pubic hair,
bluish gray skin color, and sores in the genital
area.
• Treatment includes thorough washing of
clothing, furniture, and linens.
• Takes 2 to 3 weeks to kill all larval forms.
• Usually transmitted sexually but can also be
caught from lying on sheets or sitting on a toilet
seat that an infected person has used.
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HIV/AIDS
• Acquired Immunodeficiency Syndrome
(AIDS)
• Human Immunodeficiency Virus (HIV)
– At the end of 2009, there were approximately
33.3 million people worldwide living with HIV.
– Approximately 1.1 million people are infected
with HIV in the United States, and at least
617,025 have died.
– In 2009, 42,959 new HIV/AIDS cases were
diagnosed here.
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How HIV Is Transmitted
• Engaging in high-risk behaviors
– Exchange of body fluids
– Injecting drugs
– Having received a blood transfusion prior to
1985
– Mother-to-child (perinatal) transmission
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Sources of HIV Infection in Men and Women
in the United States, 2009
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Symptoms of HIV/AIDS
• Incubation time varies greatly.
– For HIV-positive adults who receive no medical
treatment, AIDS will develop in 8 to 10 years.
• Opportunistic infections are characteristic of the
disease.
• An AIDS diagnosis occurs when a person has a
dangerously low CD4 count (below 200 cells per
cubic milliliter of blood) or contracts one or more
opportunistic infections (e.g. Kaposi's sarcoma
or Pneumocystis carinii pneumonia).
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Testing for HIV Antibodies
• Blood test known as ELISA (enzymelinked-immunosorbent assay)
• Western blot test follows two positive
ELISA tests
• These tests detect antibodies for HIV.
• Whether a person with HIV develops AIDS
depends to some extent on the strength of
that person's immune system.
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HIV/AIDS
• New Hope and Treatments
– New drugs slow progression of virus
– Medications are currently very expensive and cause
many side effects.
– Protease inhibitors and reverse transcriptase
inhibitors
• Preventing HIV Infection
– No vaccine currently available
– Reduce risk by responsible choices and behaviors.
• If you don't exchange bodily fluids, you won't get the disease.
– Abstinence or safe sexual practices
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Noninfectious Conditions
• There are many noninfectious conditions other than
major ailments such as cancer and heart disease.
• Most other chronic conditions can be prevented or the
symptoms alleviated.
• Generally they are not transmitted by pathogen or
personal contact.
• Lifestyle and personal habits are often implicated as
underlying causes.
• Healthy lifestyle changes and public health efforts at
research, prevention, and control can minimize effects of
these diseases.
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Chronic Lung Diseases
• Any disease or disorder in which lung
function is impaired is considered a lung
disease.
– Lung disease is the fourth leading cause of
death in the United States.
– Can be caused by a range of factors.
• Chronic Obstructive Pulmonary Diseases
(COPDs) is the term used to describe
specific conditions.
– Includes chronic bronchitis and emphysema,
but not asthma.
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Bronchitis and Emphysema
• Bronchitis
– Inflammation of lining of bronchial tubes
– Less air is able to flow from the lungs and heavy mucus begins
to form
– Acute bronchitis: when symptoms improve in a few weeks
– Chronic bronchitis: when the symptoms of bronchitis last for at
least 3 months of the year for 2 consecutive years
• Emphysema
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Gradual destruction of alveoli
Becomes more and more difficult to exhale
Victim struggles to take in air
Chest cavity expands over time ("barrel chest")
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Asthma
• Long-term chronic inflammatory disorder
that blocks airflow to the lungs
• Air pollutants, particulates, smoke,
allergens, and stress can trigger an
asthma attack.
• Extrinsic (allergic asthma) or intrinsic
(nonallergic)
• Exercise-induced asthma (EIA)
• Relaxation techniques and medications
can offer relief.
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Headaches
• Tension headaches are caused by muscular
contractions in the neck or head.
– The most common type of headache
– Treatments: relaxation, hot water, massage, and pain
medication
• Migraine headaches have severe debilitating
symptoms.
– Treatments: rye fungus ergot and other medications
• Cluster headaches are more rare forms; "killer"
or "suicidal" pain.
– Treatments: oxygen therapy, drugs, and surgery
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Chronic Fatigue Syndrome (CFS)
• Symptoms include chronic fatigue,
headaches, fever, sore throat, enlarged
lymph nodes, depression, poor memory,
general weakness, and nausea.
• It is believed that the syndrome has strong
psychosocial roots.
• Treatment includes improved nutrition,
rest, counseling for depression, exercise,
and development of a strong support
network.
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Low Back Pain (LBP)
• Low back pain is the major cause of disability for people
aged 20 to 45.
• To Reduce LBP
– Purchase a high-quality, supportive mattress, and avoid sleeping
on your stomach.
– Avoid high-heeled shoes, and wear shoes with good arch
support.
– Avoid carrying heavy backpacks or bookbags on one shoulder.
– Control your weight.
– Warm up and stretch before exercising.
– When lifting something heavy, use your leg muscles.
– Buy a chair with good lumbar support.
– Move your car seat up so your knees are elevated slightly.
– Exercise regularly.
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Repetitive Motion Disorders
• Repetitive motion disorders include carpal
tunnel syndrome, bursitis, tendonitis, and
ganglion cysts.
• The best way to prevent a repetitive
motion disorder is to educate yourself and
use better ergonomic workplace designs.
• Treatment involves physical and
occupational therapy.
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