INFECTIOUS DISEASE

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INFECTIOUS DISEASE
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What is Infectious Disease?

• A disease caused by the presence of a living
  thing in the body.

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What are Pathogens?

• Organisms that cause disease.

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Four Types of Pathogens

• Bacteria
• Viruses
• Fungi
• Protists

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BACTERIA

• One-celled microorganisms that cause a wide
  variety of diseases. Some bacteria damage cells
  directly, however others damage them indirectly
  by releasing toxins, or poisons, into your body.
  They are LIVING.

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VIRUSES

• Tiny particles, much smaller than bacteria that
  cannot reproduce unless they are inside living
  cells. The cells are damaged or destroyed in the
  process, releasing new viruses to infect other
  cells. Viruses are NONLIVING! They are
  particles- NOT CELLS!

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FUNGI

• Fungi, which include molds and yeasts, also cause
  some infectious diseases. Fungi grow in warm,
  dark, moist areas. Two examples are athletes
  foot and ringworm. They are LIVING!

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PROTISTS

• An organism that cannot be classified as an
  animal, plant, or fungus. One example is Malaria,
  an infection of the blood. Protists are LIVING!

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How Do Pathogens Spread?

• Pathogens can spread through contact with either
  an infected person soil, food, or water a
  contaminated object or an infected animal.

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Infected People

• Direct physical contact (kissing, shaking hands,
  etc)
• Indirect contact (sneezing, coughing, etc)

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Soil, Food, Water

• Some pathogens occur naturally in the
  environment.
• Some pathogens contaminate food and water,
  spreading disease when drinking and eating.

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Contaminated Objects

• Some pathogens can survive outside a persons
  body.
• Contact with contaminated objects can infect a
  person (towels, silverware, etc).

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Infected Animals

• If an animal is infected with a pathogen and
  bites a person, it can pass the pathogen to the
  person.
• Example Rabies, Lyme Disease, etc.