Infection, Immunity, and Noninfectious Disease

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Infection, Immunity, and Noninfectious Disease
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Diseases

• 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

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Genetic Diseases

• Two types Inherited diseases (inherit
  defective gene) and diseases caused by errors
  when gametes are formed
• Defective (mutated) genes caused by ionizing
  radiation, toxic chemicals, drugs
• Common inherited diseases in the U.S.
• Sickle-cell anemia
• Cystic fibrosis
• Duchenne muscular dystrophy

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Noninfectious Diseases Caused by an Interaction
of Genes and Environment

• Asthma
• Narrowed airway passages and difficulty breathing
• Attacks can be triggered by air pollution, URIs,
  smoke, dust
• Ulcers
• Diabetes mellitus
• Migraine headaches
• Cardiovascular disease
• Cancer

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Trends in Infectious Disease

• 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

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Chain of Infection

• Agent of Infection (Pathogen)
• Transmission
• Host

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Pathogens

• 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

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Pathogens (contd)

• 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 athletes foot, yeast
  infections

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Ringworm
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Toenail fungus
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Pathogens (contd)

• Protozoans (single-celled organisms with a
  complex cell structure)
• Cause disease such as malaria, trich infections
• 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 (contd)

• Arthropods
• Lice, fleas, mites, and ticks
• Cause infestations of various body parts

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Transmission of Disease

• Noncommunicable
• Communicable

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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

• 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)

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Host

• Stress can reduce resistance to infection
• Exhaustive exercise can lower immune system
  function
• Race and age affect resistance or susceptibility
  to disease

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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

• Spread from person-to-person by intimate contact
• Caused by certain viruses, bacteria, yeasts, and
  protozoans
• Infestations caused by certain mites and lice

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HIV Transmission

• Sexual contact with infected person
• Semen, vaginal secretions, or blood
• Tears in skin and mucous membranes
• Exposure to infected blood or blood products
• Shared needles
• Blood transfusions
• Placental transfer during fetal development,
  labor/delivery, and breastfeeding

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Yeast Infections

• 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

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SUMMARY

• 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

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SUMMARY (contd)

• 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 bodys reaction to the pathogen

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SUMMARY (contd)

• Many drugs have been developed to combat
  infection
• Adolescents and young adults are at highest risk
  for contracting STIs