The Chain of Infection

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The Chain of Infection

• And how to break it

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• To grow and spread, most microorganisms prefer
• Warm, dark environment
• Moisture
• Source of food
• Human body fits the criteria!

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For disease to occur and spreadcertain
conditions must be met
Chain of Infection
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1. Need an infectious agent, a.k.a., a pathogen

• Bacteria
• Exogenous starts outside the body
• Endogenous starts inside the body
• Other infectious agents include viruses, fungi,
  protozoa

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2. Reservoir

• A place the pathogen can live
• Human body
• Animals
• Environment
• Fomites contaminated inanimate objects-

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3.Portal of Exit

• Way of leaving the reservoir in which it has been
  growing
• Blood
• Tears
• Feces
• Urine
• Saliva
• Draining wounds

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4. Means of Transmission-

• Needs to be transported to another reservoir
• Direct person to person contact- contaminated
  hands most common
• Indirect contact-
• coming in contact with contaminated equipment,
  food, insect bite

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5. Portal of Entry

• Breaks in skin
• Breaks in mucous membranes
• Respiratory tract
• Digestive tract
• Circulatory system
• Genitourinary tract

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How your body fights off a causative agent

• Mucous membranes-trap
• Cilia transport.
• Coughing and sneezing-- expel
• Hydrochloric acid in the stomach-- destroy
• Tears in the eyes-bacteriocidal
• Fever-destroy
• Inflammation-white cells
• Immune response-antibodies

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6. Susceptible host

• Large numbers of pathogens.
• Body defenses are weak
• Results in susceptible host, or a person likely
  to get an infection or disease
• Chain of infection can be broken at any point