Describe the infectious disease process

Infectious disease agent

• Typically microorganisms e.g. bacteria, fungi, parasites

Reservoir

• Normal habitat where the agent lives and multiplies

• E.g. rabies is dogs not humans

• 4 types or carriers

  • Systematic cases/carries

    • Human carriers types

      • Incubatory = transmit infectious agent before symptoms begin

      • Inapparent = transmit infection without ever getting it themselves e.g. polo

      • Convalescent = received from infectious but can still infect others

      • Chronic = received from illness but can harbour infection for months/years

  • Animal

  • Insects

  • Environments

Portal of exit

• Any route that allows pathogen to leave host

  • Alimentary e.g vomiting

  • Genitourinary

  • Respiratory

  • Skin

  • Trans placental

Mode of transmission

• Direct transmission

  • instantaneous

• Indirect transmission

  • Not direct human to human interaction

  • Caused by flies, water, mosquito, airborne etc.

Portal of entry

• Tool by which infection can enter suspectable host

  • Inhalation

  • Absorption

  • Ingestion

  • Inoculation

  • Introduction

Host susceptibility

• Depends on variety of factors

  • Age, gender, lifestyle, medical history, heredity, host physical barriers