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Key Concepts in Epidemiology and Public Health

  • Epidemiology Basics:

    • Studies health events among populations, not individuals.
    • Focused on monitoring disease incidence, prevalence, and mortality rates.

  • Public Health Role:

    • Aim to maintain population health and prevent negative health outcomes.
    • Informed by epidemiological studies, such as dietary impacts on health.
    • CDC tracks various health metrics, including cancer, maternal mortality, and Infectious diseases.

  • Historical Figures:

    • Florence Nightingale: Improved sanitary conditions in hospitals during the Crimean War, attributing outcomes to hygiene rather than battlefield wounds.
    • John Snow: Identified the water source of the 1854 cholera epidemic through mapping cases in London.

  • Key Epidemiological Concepts:

    • Prevalence: Total existing cases in a population.
    • Incidence: New cases over a specified time period.
    • Mortality Rate: Deaths in a population from a specific cause.

  • Types of Diseases:

    • Endemic: Steady frequency in a specific location (e.g., malaria in the South U.S.).
    • Epidemic: Rapid increase in cases within a local population.
    • Pandemic: Widespread epidemic across multiple continents.
    • Sporadic: Occasional outbreaks with no consistent pattern.

  • Disease Transmission Dynamics:

    • Point Source Epidemic: Single source exposure (e.g., contaminated food).
    • Common Source Epidemic: Continuous exposure over time (e.g., water supply).
    • Propagated Epidemic: Person-to-person transmission, leading to exponential growth.

  • Factors Influencing Spread:

    • Cultural practices, population density, and seasonal changes affect epidemic patterns (e.g., winter spikes for respiratory diseases).

  • Testing & Screening:

    • Screening Tests: Quick, non-invasive tests to identify health issues.
    • Diagnostic Tests: More invasive, fewer false positives/negatives, e.g., biopsies.

  • Causation in Epidemiology:

    • Koch's Postulates: Framework for determining disease causation, now supplemented by modern molecular methods like PCR.

  • Current Challenges:

    • Emerging and re-emerging diseases linked to climate change and global travel (e.g., increased Lyme disease cases in the Midwest).
    • Vaccine adverse events tracking to monitor vaccine safety (VAERS).

  • Important Numbers:

    • R-naught Value (R0): Measures infection spread potential. COVID ~2, Measles ~16.
    • Case Fatality Rate: Proportion of deaths among diagnosed cases, assists in evaluating disease impact.