Transcript Trends in Infectious Disease

Infection, Immunity,
and Noninfectious
Disease
Diseases
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Processes that affect proper body functioning
accompanied by associated signs and symptoms
Noninfectious diseases - caused by genetic
abnormalities, environmental factors, or a
combination of both
 Cystic fibrosis, lead-poisoning, asthma
Infectious diseases - caused by pathogens such as
bacteria, viruses, fungi, parasitic worms
 Colds, flu, sexually transmitted infections
Genetic Diseases
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Two types: Inherited diseases (inherit “defective” gene)
and diseases caused by errors when gametes are formed
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Defective (mutated) genes caused by ionizing radiation, toxic
chemicals, drugs
Common inherited diseases in the U.S.
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Sickle-cell anemia
Cystic fibrosis
Duchenne muscular dystrophy
Noninfectious Diseases
Caused by an Interaction of
Genes and Environment
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Asthma
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Narrowed airway passages and difficulty breathing
Attacks can be triggered by air pollution, URIs, smoke,
dust
Ulcers
Diabetes mellitus
Migraine headaches
Cardiovascular disease
Cancer
Trends in Infectious Disease
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Infectious diseases are not significant contributors
to death in the U.S. today
Worldwide, infectious diseases are the leading cause
of death
Many strains of bacteria have become resistant to
antibiotics
With international travel commonplace,
transmission of infection is a worldwide concern
Chain of Infection
 Agent
of Infection (Pathogen)
 Transmission
 Host
Pathogens
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Bacteria (unicellular organisms with a simple cell
structure)
 Cause diseases such as strep throat,
pneumonia, food infection
Rickettsias (bacterialike organisms that live
within host cells)
 Cause diseases such as typhus, Rocky
Mountain Spotted Fever
Pathogens (cont’d)
 Viruses
(hereditary material with a
protein coat)
 Cause diseases such as cold, flu,
mumps, measles, chicken pox,
hepatitis, HIV infection
 Fungi (cause opportunistic infections)
 Cause diseases such as athlete’s foot,
yeast infections
Ringworm
Toenail fungus
Pathogens (cont’d)
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Protozoans (single-celled organisms with a complex
cell structure)
 Cause disease such as malaria, “trich” infections
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Parasitic worms
Tapeworms, roundworms, flukes
 Live in digestive system and cause digestive
disorders. Flukes can also inhabit the liver, lungs, or
veins.
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Pathogens (cont’d)
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Arthropods
 Lice, fleas, mites, and ticks
 Cause infestations of various body parts
Transmission of Disease
Noncommunicable
Communicable
Noncommunicable Diseases
Caused by: Growth of bacteria that
normally inhabit the body
 Skin infections
 Ingestion of toxins or poisons produced
by some bacteria
 Food poisoning or food infection
 Pathogens that infect people via
environment or animal sources
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Communicable Diseases
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Transmitted from person to person by
 direct or indirect contact
 a common vehicle (food, water, a common
drinking glass)
 the air
 vectors (organisms other than humans, such
as mosquitoes)
Host
 Stress
can reduce resistance to
infection
 Exhaustive exercise can lower immune
system function
 Race and age affect resistance or
susceptibility to disease
Treating Infections
Antibiotics (kill or inhibit growth of
bacteria)
 Over-the-counter medications can
sometimes relieve symptoms
 Specific medications have been developed
to treat certain viral and protozoan
infections, and worm infestations
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Sexually Transmitted Infections
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Spread from person-to-person by intimate
contact
Caused by certain viruses, bacteria, yeasts, and
protozoans
Infestations caused by certain mites and lice
HIV Transmission
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Sexual contact with infected person
Semen, vaginal secretions, or blood
 Tears in skin and mucous membranes
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Exposure to infected blood or blood products
Shared needles
 Blood transfusions
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Placental transfer during fetal development,
labor/delivery, and breastfeeding
Yeast Infections
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Candidiasis
Acquired through intercourse or develops in women
after taking antibiotics
Itching, burning, irritation, swelling, and white vaginal
discharge
Can be treated with OTC antifungal creams
Males may experience irritation, swelling, and a rash or
white patches
SUMMARY
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Noninfectious diseases have hereditary or
environmental causes, or a combination of both
Genetic diseases are inherited
Two primary causes of infectious diseases are bacteria
and viruses
The human body combats infectious disease with both
specific and nonspecific types of immunity
SUMMARY (cont’d)
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The severity of a disease depends on:
the type of organism
 its virulence
 how it spreads in the body
 the chemicals it produces
 its ability to combat the defense mechanisms of the
body
 the body’s reaction to the pathogen
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SUMMARY (cont’d)
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Many drugs have been developed to combat
infection
Adolescents and young adults are at highest risk
for contracting STIs