MPH Review Slides

Epidemiology

  • Fundamental Assumptions

    • Diseases do not occur by chance

    • Their distribution indicates factors influencing disease processes.

Population Focus

  • Focuses on health and disease occurrence in the population.

  • Analysis of what happens to many individuals, in contrast to clinical medicine, which focuses on individual health issues.

Objectives of Epidemiology

  • Identify disease etiology and risk factors.

  • Determine disease extent in the community.

  • Study natural history and prognosis of diseases.

  • Evaluate preventive and therapeutic measures.

  • Provide a foundation for health policy.

Importance of Understanding Disease Factors

  • Identifying factors like reservoirs and transmission reduces morbidity and mortality.

  • Guides distribution of resources for interventions and training.

  • Basis for policies and local regulations.

Mortality Overview

  • Historical comparison of causes of death in the USA:

    • 1900 vs. 2010 (Rates per 100,000):

      • Total decline in mortality by 54%.

      • Leading causes of death shifted from infections to chronic diseases.

        • Key causes in 1900: Cancer (64.0), Heart disease (137.4).

        • Key causes in 2010: Heart Disease (192.9), Cancer (185.9), Accidents (38.2).

      • COVID-19 noted as a top cause in 2020.

Historical Perspective on Preventive Medicine

  • Established during the American Revolution emphasizing:

    • Hygiene, nutrition, and avoidance of extreme conditions.

    • Health education and immunization importance.

    • Proper sanitation and waste disposal in military camps.

Command Authority in Military PM

  • Commanders (CDRs) responsible for troop health.

  • Preventive medicine seldom operates through medical channels alone.

  • Strong relationship with special staff for effective communication between command and military medicine.

Milestones in Military Preventive Medicine

  • Key figures:

    • James Tilton: created well-ventilated hospitals.

    • Walter Reed: identified Aedes mosquito as a yellow fever vector.

    • Joseph Lyster: innovated the Lyster bag for water chlorination.

Levels of Prevention

  • Primary Prevention: Prevent illness before it starts (e.g., immunizations).

  • Secondary Prevention: Early diagnosis and prompt treatment to avoid severe problems.

  • Tertiary Prevention: Reduce complications from existing diseases; includes rehabilitation.

Evidence-Based Medicine Role

  • USPSTF Recommendations (based on evidence strength):

    • Grading from A (high certainty of net benefit) to D (harms outweigh benefits).

  • Focuses only on asymptomatic individuals in primary care settings.

Key Definitions

  • Communicable Disease: Infectious illness transmitted to a susceptible host from an infected source (person, animal, or environment).

  • Inapparent Disease: Latent infections with no active signs; carriers can transmit diseases without showing symptoms.

Epidemiologic Triad

  • Host: Factors such as prior exposure, immune response, and personal customs.

  • Agent: Includes viruses, bacteria, and other pathogens with properties like toxicity and virulence.

  • Environment: Climate, social structure, and population density impact disease dynamics.

Modes of Transmission

  • Direct Transmission: Contact, droplet spread.

  • Indirect Transmission:

    • Airborne, vector, and vehicle-borne transmissions (e.g., food, water).

Disease Distribution Terms

  • Endemic: Regular presence; baseline levels.

  • Epidemic: Excess occurrence beyond normal expectations.

  • Pandemic: Worldwide epidemic scenario.

Morbidity and Frequency Measures

  • Includes attack rates, incidence, prevalence, and point/period prevalence to assess health status in populations.

Infection Control Strategies

  • Understanding disease pathways aids in systematic control measures including vaccination and sanitation.

Nutrition and Health

  • Historical milestones emphasize the role of diet, infection control, vaccination, and sanitation in improving public health.

Foodborne Illness Mechanisms

  • Foodborne Infection: Pathogens infect the intestines causing illness (e.g., Salmonella).

  • Food Intoxication: Illness due to toxins from pre-existing pathogens (e.g., Staphylococcus aureus).

Travelers’ Precautions

  • Traveler’s Diarrhea: Common among travelers; management includes rehydration and self-treatment options.

  • Animal Bites: Immediate care is crucial for rabies prevention following bites from potentially rabid animals.

Heat-Related Illnesses

  • Combined efforts in monitoring and immediate response to conditions like heat exhaustion and heat stroke in military personnel.