ls /home/daytona/workspace/ 2>/dev/null && mkdir -p /home/daytona/workspace/epid…

~/epidemiology-ppt/epidemiology_ppt.js

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pres.layout = "LAYOUT_16x9";
pres.title = "Epidemiology - Community Medicine";
pres.author = "Based on Park's Textbook of Preventive & Social Medicine";

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// ─── HELPERS ────────────────────────────────────────────────────────────────
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// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SLIDE 1 – TITLE SLIDE
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
{
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  s.addText("EPIDEMIOLOGY", { x: 0.5, y: 0.5, w: 9, h: 1.6, fontSize: 52, bold: true, color: C.white, align: "center", fontFace: "Calibri", charSpacing: 3 });
  s.addText("Community Medicine for Postgraduate Students", { x: 0.5, y: 2.1, w: 9, h: 0.7, fontSize: 20, color: "A8C8F0", align: "center", fontFace: "Calibri" });
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  s.addText("Covering: Concepts • Methods • Measures • Study Designs • Screening • Bias • Causation", { x: 0.5, y: 3.7, w: 9, h: 0.5, fontSize: 12, color: "7AAFC8", align: "center", fontFace: "Calibri" });
  s.addText("July 2026", { x: 0.5, y: 5.1, w: 9, h: 0.35, fontSize: 11, color: "6A9EC5", align: "center", fontFace: "Calibri" });
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// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SLIDE 2 – TABLE OF CONTENTS
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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  const topics = [
    ["01", "Definition & History of Epidemiology"],
    ["02", "Epidemiological Triad & Natural History of Disease"],
    ["03", "Aims & Uses of Epidemiology"],
    ["04", "Basic Measurements (Rates, Ratios, Proportions)"],
    ["05", "Mortality & Morbidity Measures"],
    ["06", "Epidemiological Study Designs"],
    ["07", "Descriptive Epidemiology (Time, Place, Person)"],
    ["08", "Analytical Epidemiology (Case-Control & Cohort)"],
    ["09", "Experimental Epidemiology (RCT, Field & Community Trials)"],
    ["10", "Disease Causation & Screening"],
    ["11", "Bias, Confounding & Surveillance"],
    ["12", "Infectious Disease Epidemiology"],
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// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 1 – DEFINITION & HISTORY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 1", "Definition & History of Epidemiology");

definitionSlide(pres,
  "Epidemiology",
  "The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the prevention and control of health problems.",
  "John M. Last, Dictionary of Epidemiology"
);

contentSlide(pres, "Definition – Key Elements", [
  "Distribution: Who gets the disease? Where? When? → describes frequency & pattern",
  "Determinants: Factors that cause or influence disease occurrence (biological, environmental, social, behavioral)",
  "Health-related states: Not just disease – also health, injuries, disability, death, behaviors",
  "Specified populations: Denominator-based thinking; population at risk is essential",
  "Application: Goal is always prevention & control of health problems",
  "Epidemiology is both a science (uses rigorous methods) and a practical tool (for public health action)",
], { fontSize: 13.5 });

contentSlide(pres, "Historical Milestones", [
  "Hippocrates (400 BC): First to use term 'epidemic' and 'endemic'; related disease to environment ('On Airs, Waters and Places')",
  "John Graunt (1662): Analyzed London Bills of Mortality – first quantitative analysis of mortality data",
  "James Lind (1747): First clinical trial – citrus fruits prevent scurvy in sailors",
  "Edward Jenner (1796): Smallpox vaccination – first experimental epidemiology",
  "John Snow (1854): Broad Street pump; cholera epidemic in London – 'Father of Epidemiology'",
  "William Farr (1839): Vital statistics; first Registrar General of England; concept of 'epidemic curve'",
  "Doll & Hill (1950): Landmark case-control study linking smoking and lung cancer",
  "Framingham Heart Study (1948–): Cohort study establishing CVD risk factors",
], { fontSize: 13 });

contentSlide(pres, "Scope of Epidemiology", [
  "Communicable diseases – historically the foundation of epidemiology",
  "Non-communicable diseases (NCD) – CVD, cancer, diabetes, mental disorders",
  "Injuries – road traffic accidents, occupational hazards",
  "Environmental epidemiology – air, water, soil pollutants",
  "Social epidemiology – socioeconomic determinants of health",
  "Pharmacoepidemiology – drug safety and effectiveness in populations",
  "Molecular/Genetic epidemiology – genomic basis of disease distribution",
  "Clinical epidemiology – application of epidemiological methods in clinical settings",
  "Reproductive & Perinatal epidemiology",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 2 – EPIDEMIOLOGICAL TRIAD & NATURAL HISTORY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 2", "Epidemiological Triad & Natural History of Disease");

contentSlide(pres, "Epidemiological Triad (Agent–Host–Environment)", [
  "AGENT: Cause of disease. Infectious (bacteria, virus, fungi, parasite) or non-infectious (chemicals, radiation, nutritional deficiencies, tobacco, trauma)",
  "HOST: The human (or animal) organism. Factors: immunity, genetic makeup, age, sex, nutrition, behaviour, occupation",
  "ENVIRONMENT: External surroundings. Physical (climate, geography), biological (vectors, reservoirs), social (crowding, poverty), cultural",
  "TIME: 4th element – accounts for incubation period, duration of illness, chronological changes in disease frequency",
  "Disease occurs when the Agent-Host-Environment interaction is imbalanced",
  "Park (2007): 'The mere presence of agent, host and favourable environmental factors is not sufficient; what is required is interaction of these three factors'",
], { fontSize: 13.5 });

contentSlide(pres, "Natural History of Disease", [
  "DEFINITION: The course of disease from inception to resolution, without any medical intervention",
  "Phase 1 – Pre-pathogenesis: Agent has not yet entered host. Interaction of agent, host, environment occurs in external environment. 'Man exposed to risk of disease'",
  "Phase 2 – Pathogenesis: Begins with entry of agent into susceptible host. Sub-phases: early pathogenesis → advanced disease → outcome (recovery / disability / death)",
  "Stimulus-Period: Incubation period in infectious diseases; induction period in chronic diseases",
  "Concept of Iceberg: The visible (clinical) cases are only tip; large subclinical/latent cases lie below the surface",
  "Levels of Prevention correspond to stages of natural history (see next slide)",
], { fontSize: 13.5 });

contentSlide(pres, "Levels of Prevention (Leavell & Clark)", [
  "PRIMARY PREVENTION: Action taken before disease occurs. Targets pre-pathogenesis phase",
  "  → Health Promotion: education, nutrition, sanitation, housing improvements",
  "  → Specific Protection: immunization, chemoprophylaxis, use of helmets, fluoridation",
  "SECONDARY PREVENTION: Early detection & prompt treatment. Targets early pathogenesis",
  "  → Early diagnosis: screening, case-finding",
  "  → Prompt treatment: preventing progress to advanced disease, reducing communicability",
  "TERTIARY PREVENTION: Limiting disability and rehabilitation. Targets advanced pathogenesis & disability",
  "  → Disability limitation: surgery, physiotherapy",
  "  → Rehabilitation: physical, social, vocational rehabilitation",
  "PRIMORDIAL PREVENTION (4th level): Preventing emergence of risk factors in the first place (social & environmental changes)",
], { fontSize: 12.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 3 – AIMS & USES
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 3", "Aims & Uses of Epidemiology");

contentSlide(pres, "Aims of Epidemiology (IEA)", [
  "According to the International Epidemiological Association (IEA), the three main aims are:",
  "(a) To describe the distribution and magnitude of health and disease problems in human populations",
  "(b) To identify aetiological factors (risk factors) in the pathogenesis of disease",
  "(c) To provide data essential to planning, implementation and evaluation of health services for prevention, control and treatment",
  "Ultimate aim: Effective action to eliminate or reduce health problems and promote health and well-being of society as a whole",
  "These aims are achieved through: Descriptive studies, Analytical studies, and Experimental (intervention) studies",
], { fontSize: 14 });

contentSlide(pres, "Uses of Epidemiology (Morris – 7 Uses)", [
  "1. Study of history of disease: Rise and fall of disease trends; predict future epidemics; identify emerging diseases",
  "2. Community diagnosis: Identify and quantify health problems in a community by mortality and morbidity rates",
  "3. Working of health services: Evaluate adequacy and effectiveness of health services",
  "4. Individual risk and chances: Calculate individual risk of getting a disease based on characteristics",
  "5. Complete the clinical picture of disease: Identify the full spectrum (iceberg phenomenon); describe natural history",
  "6. Identification of syndromes: Cluster of signs/symptoms not previously recognized as a disease entity (e.g., AIDS, SARS)",
  "7. Search for causes (aetiology): Identify risk factors through analytical methods; generate and test hypotheses",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 4 – MEASUREMENTS
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 4", "Basic Measurements in Epidemiology");

contentSlide(pres, "Tools of Measurement: Rate, Ratio & Proportion", [
  "RATE: Expresses probability (risk) of disease in a population over a specified time. Numerator included in denominator. Has a time element. Example: Incidence rate = New cases / Population at risk × 10ⁿ",
  "RATIO: Relationship between two quantities, numerator NOT part of denominator. Example: Sex ratio, Stillbirth rate, Maternal mortality ratio",
  "PROPORTION: Ratio where numerator IS part of denominator; no time element. Example: Proportional mortality ratio (PMR)",
  "CRUDE RATES: Refer to entire population (crude birth rate, crude death rate)",
  "SPECIFIC RATES: Refer to a particular subgroup (age-specific, sex-specific, cause-specific)",
  "STANDARDIZED (ADJUSTED) RATES: Used for comparing populations with different age/sex structures (direct & indirect standardization)",
], { fontSize: 13.5 });

contentSlide(pres, "Mortality Measures", [
  "Crude Death Rate (CDR): Total deaths / Mid-year population × 1000",
  "Age-specific Death Rate: Deaths in age group / Mid-year population in that age group × 1000",
  "Infant Mortality Rate (IMR): Deaths under 1 year / Live births × 1000 (sensitive indicator of socioeconomic development)",
  "Neonatal Mortality Rate (NMR): Deaths in first 28 days / Live births × 1000",
  "Perinatal Mortality Rate: (Still births + Deaths in first week) / (Live births + Still births) × 1000",
  "Maternal Mortality Rate (MMR): Maternal deaths / Live births × 100,000 (Key indicator of reproductive health & healthcare quality)",
  "Case Fatality Rate (CFR): Deaths from a disease / All cases of that disease × 100 (measures severity of disease)",
  "Proportional Mortality Rate (PMR): Deaths from specific cause / Total deaths × 100",
], { fontSize: 12.5 });

contentSlide(pres, "Morbidity Measures", [
  "INCIDENCE RATE: Number of NEW cases occurring in a defined population during a specified time / Population at risk × 10ⁿ",
  "  → Measures probability (risk) of developing disease; indicates speed of disease spread",
  "PREVALENCE: Number of ALL existing cases (new + old) at a given time / Total population × 10ⁿ",
  "  → Point prevalence: cases at a specific moment",
  "  → Period prevalence: cases over a defined period",
  "RELATIONSHIP: Prevalence ≈ Incidence Rate × Mean duration of disease (P = I × D)",
  "ATTACK RATE: Number of cases of disease / Population at risk × 100 (used in outbreak investigation; a special type of incidence rate)",
  "SECONDARY ATTACK RATE (SAR): New cases in household contacts / Total susceptible contacts × 100 (measures transmissibility)",
], { fontSize: 13 });

contentSlide(pres, "Other Important Epidemiological Measures", [
  "Years of Potential Life Lost (YPLL): Measures premature mortality; YPLL = (Threshold age - Age at death) summed for all deaths",
  "Disability-Adjusted Life Year (DALY): = YLL (Years of Life Lost) + YLD (Years Lived with Disability). Global Burden of Disease metric",
  "Quality-Adjusted Life Year (QALY): Used in health economics for cost-effectiveness analysis",
  "Relative Risk (RR): Incidence in exposed / Incidence in unexposed. Measures strength of association (used in cohort studies)",
  "Odds Ratio (OR): Odds of exposure in cases / Odds of exposure in controls. Approximates RR when disease is rare (used in case-control studies)",
  "Attributable Risk (AR): Incidence in exposed – Incidence in unexposed. Measures public health impact",
  "Population Attributable Risk (PAR): Proportion of disease in total population attributable to a specific exposure",
], { fontSize: 12.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 5 – STUDY DESIGNS OVERVIEW
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 5", "Classification of Epidemiological Study Designs");

contentSlide(pres, "Classification of Epidemiological Studies (Park)", [
  "A. OBSERVATIONAL STUDIES (investigator measures but does not intervene):",
  "   1. Descriptive Studies: Ecological/correlational; cross-sectional/prevalence",
  "   2. Analytical Studies: Case-control (case-reference); Cohort (follow-up)",
  "B. EXPERIMENTAL STUDIES (intervention studies – investigator intervenes):",
  "   1. Randomized Controlled Trial (RCT): patients as unit of study",
  "   2. Field Trials: healthy people as unit of study",
  "   3. Community Trials: communities as unit of study",
  "HIERARCHY OF EVIDENCE: Systematic Reviews/Meta-analysis > RCTs > Cohort > Case-Control > Cross-sectional > Ecological",
  "Key requirement: Always need clear definition of 'case' and 'exposure' before any study",
], { fontSize: 13.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 6 – DESCRIPTIVE EPIDEMIOLOGY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 6", "Descriptive Epidemiology");

contentSlide(pres, "Descriptive Epidemiology – Overview", [
  "DEFINITION: Studies that describe the distribution of disease in a population – WHO gets the disease, WHERE and WHEN",
  "Variables used: Person, Place and Time (The 3 Epidemiological Variables)",
  "PURPOSE: Hypothesis-generating (not hypothesis-testing); provides clues to aetiology",
  "Uses: (a) Provide data on disease load and types; (b) Generate aetiological hypotheses; (c) Background data for health service planning; (d) Describe variations in disease by time, place and person",
  "Types: Ecological/Correlational studies; Cross-sectional studies; Case reports & case series",
  "Limitation: Cannot establish causation; only identifies associations; vulnerable to ecological fallacy",
], { fontSize: 13.5 });

contentSlide(pres, "Person Variables in Descriptive Epidemiology", [
  "AGE: Most important variable. Disease frequency varies markedly with age (e.g., leukemia in children, CHD in elderly)",
  "SEX: Males vs females differ in exposure and biological susceptibility (e.g., lung cancer higher in males historically)",
  "RACE/ETHNICITY: Genetic & social/cultural factors (e.g., sickle cell disease in Africans, Tay-Sachs in Ashkenazi Jews)",
  "MARITAL STATUS: Affects disease occurrence (e.g., cervical cancer higher in married women; mental illness higher in divorced)",
  "OCCUPATION: Occupational exposures (e.g., mesothelioma and asbestos workers, black lung in coal miners)",
  "SOCIOECONOMIC STATUS: Education, income, housing – affect disease exposure and health seeking behavior",
  "RELIGION/CUSTOMS: Dietary practices, cultural habits (e.g., circumcision and penile cancer, diet and CHD)",
], { fontSize: 13 });

contentSlide(pres, "Place & Time Variables", [
  "PLACE VARIABLES:",
  "  → International variation: Disease prevalence differs between countries (e.g., stomach cancer highest in Japan)",
  "  → National variation: Urban-rural differences (e.g., higher CHD in urban, higher infectious diseases in rural)",
  "  → Local variation: Within-city spot maps help identify point source outbreaks (John Snow's map of Broad Street pump)",
  "TIME VARIABLES:",
  "  → Secular/Long-term trends: Changes over decades (e.g., declining TB mortality before antibiotics)",
  "  → Cyclic trends (Epidemics): Regular periodic rises and falls (e.g., influenza every 2-3 years)",
  "  → Seasonal variation: e.g., cholera in summer-monsoon; measles in winter-spring in India",
  "  → Short-term fluctuations: Common source outbreaks; generates epidemic curve",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 7 – ANALYTICAL EPIDEMIOLOGY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 7", "Analytical Epidemiology");

twoColSlide(pres, "Case-Control vs Cohort Study – Comparison",
  "CASE-CONTROL STUDY",
  [
    "Direction: Retrospective (past exposure)",
    "Start with: Cases (disease present) & Controls (no disease)",
    "Measure: Odds Ratio (OR)",
    "Best for: Rare diseases; multiple exposures",
    "Quick, cheap, small sample size",
    "Disadvantage: Recall bias, selection bias",
    "Cannot directly calculate incidence rate",
    "Example: Doll & Hill – smoking & lung cancer",
  ],
  "COHORT STUDY",
  [
    "Direction: Prospective (follow exposure forward)",
    "Start with: Exposed & Unexposed groups",
    "Measure: Relative Risk (RR), Attributable Risk",
    "Best for: Common diseases; single exposure",
    "More expensive, time-consuming",
    "Advantage: Can directly measure incidence",
    "Can evaluate multiple outcomes",
    "Example: Framingham Heart Study",
  ],
  C.accent1, C.accent2
);

contentSlide(pres, "Case-Control Study – Design & Analysis", [
  "DESIGN: Select cases with disease & controls without disease → Look back to assess past exposure",
  "Controls: Should come from same population as cases; matched by age/sex/other confounders",
  "Types of controls: Hospital controls, population controls, neighbourhood controls",
  "MEASURE: Odds Ratio (OR) = (a×d) / (b×c) from 2×2 table",
  "OR = 1: No association; OR > 1: Positive association (risk factor); OR < 1: Negative association (protective)",
  "BIASES: Recall bias (cases remember exposure better than controls); Selection bias in control choice",
  "Matched case-control: Controls individually matched to cases; analyzed with McNemar's test",
  "Uses: Investigating disease outbreaks; rare diseases; hypothesis testing",
], { fontSize: 13.5 });

contentSlide(pres, "Cohort Study – Design & Analysis", [
  "DESIGN: Identify cohort of people free of disease → classify as exposed/unexposed → follow over time → measure incidence of disease",
  "Types: (a) Prospective/Concurrent cohort (b) Retrospective/Historical/Non-concurrent cohort",
  "MEASURES: Incidence rate, Relative Risk (RR), Attributable Risk (AR), Population Attributable Risk",
  "RR = Incidence in exposed / Incidence in unexposed",
  "AR = Incidence in exposed – Incidence in unexposed (= excess risk due to exposure)",
  "BIASES: Loss to follow-up; Neyman bias (survivor bias in retrospective); change in exposure status",
  "Advantages: Temporal sequence established; directly measures incidence; can study multiple outcomes",
  "Disadvantage: Expensive, time-consuming; not suitable for rare diseases; requires large sample",
], { fontSize: 13 });

contentSlide(pres, "Cross-Sectional & Ecological Studies", [
  "CROSS-SECTIONAL (Prevalence) STUDY:",
  "  → All variables (exposure + outcome) measured simultaneously at one point in time",
  "  → Measure: Prevalence; Prevalence Ratio or Prevalence Odds Ratio",
  "  → Uses: Community surveys, resource planning, hypothesis generation",
  "  → Limitation: Temporal sequence uncertain; cannot establish causality; prevalent cases only (survivor bias)",
  "ECOLOGICAL STUDY:",
  "  → Unit of analysis is population/group, NOT individual",
  "  → Correlate disease rates with exposure rates across different populations/regions",
  "  → Example: Salt intake vs. blood pressure across countries",
  "  → Limitation: ECOLOGICAL FALLACY – association at group level may not hold at individual level",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 8 – EXPERIMENTAL EPIDEMIOLOGY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 8", "Experimental Epidemiology");

contentSlide(pres, "Randomized Controlled Trial (RCT)", [
  "GOLD STANDARD of experimental epidemiology – highest level of evidence for causation",
  "DESIGN: Participants allocated randomly to intervention group or control group; outcome measured prospectively",
  "Randomization: Ensures equal distribution of confounders; base of internal validity",
  "Blinding: Single-blind (subjects); double-blind (subjects + investigators); triple-blind (+ statistician)",
  "PHASES of drug clinical trials: Phase I (safety/pharmacokinetics – healthy volunteers), Phase II (efficacy/dose – small patient group), Phase III (comparative efficacy – large RCT), Phase IV (post-marketing surveillance)",
  "LIMITATIONS: Ethical constraints; expensive; Hawthorne effect; may lack external validity (generalizability)",
  "CONSORT guidelines: Standardize reporting of RCTs; PRISMA for systematic reviews",
], { fontSize: 13.5 });

contentSlide(pres, "Field Trials & Community Trials", [
  "FIELD TRIAL:",
  "  → Intervention given to healthy individuals in the field to prevent disease",
  "  → Example: Vaccine field trials (Salk polio vaccine trial, 1954 – largest field trial ever; 1.8 million children)",
  "  → Unit of study: Individual healthy person",
  "  → Challenges: Very large sample sizes needed (rare outcomes); ethical issues; expensive",
  "COMMUNITY TRIAL (Community Intervention Study):",
  "  → Intervention applied to entire communities/groups",
  "  → Example: Water fluoridation for dental caries prevention; iodization of salt",
  "  → Unit of randomization: Community (not individual)",
  "  → Limitation: Community contamination; selection of comparable communities difficult; loss of statistical power",
  "ANIMAL EXPERIMENTS: Test hypotheses when human experiments not ethical; test vaccines/drugs; may not extrapolate directly to humans",
], { fontSize: 12.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 9 – DISEASE CAUSATION & SCREENING
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 9", "Disease Causation & Screening");

contentSlide(pres, "Concepts of Causation", [
  "ASSOCIATION: Statistical relationship between exposure and outcome. May be: Spurious (due to bias/confounding), Non-causal (indirect), or Causal",
  "SUFFICIENT CAUSE: A complete causal mechanism that inevitably produces disease",
  "NECESSARY CAUSE: Must be present for disease to occur (e.g., M. tuberculosis for TB); not all necessary causes are sufficient",
  "WEB OF CAUSATION (MacMahon & Pugh): Disease arises from complex interplay of multiple factors → depicted as a web/network of causes",
  "MODELS OF CAUSATION: (1) Epidemiological triad; (2) Web of causation; (3) Wheel model; (4) Multicausality model",
  "RISK FACTOR: Any attribute, exposure or behavior that increases probability of a disease. Risk factors are not necessarily causal but have predictive utility",
], { fontSize: 13.5 });

contentSlide(pres, "Hill's Criteria of Causation (Bradford Hill, 1965)", [
  "1. STRENGTH of association: High relative risk is more likely causal (smoking RR ~9 for lung cancer)",
  "2. CONSISTENCY: Same result across different populations, places, and times",
  "3. SPECIFICITY: One cause → one effect (limited to specific sites/types of workers and specific disease)",
  "4. TEMPORALITY: Cause MUST precede effect (most important criterion – the only absolute requirement)",
  "5. BIOLOGICAL GRADIENT (Dose-response): More exposure → more disease (smoking dose and lung cancer)",
  "6. PLAUSIBILITY: Association should be biologically plausible given current knowledge",
  "7. COHERENCE: Does not conflict with generally known facts of natural history and biology",
  "8. EXPERIMENT: Removal of cause reduces disease (most convincing evidence)",
  "9. ANALOGY: Similar cause-effect patterns known (e.g., thalidomide → limb defects → other drugs)",
  "Note: Only temporality is an absolute requirement; other criteria are 'viewpoints', not requirements",
], { fontSize: 12 });

contentSlide(pres, "Screening – Concepts & Criteria", [
  "DEFINITION: Presumptive identification of unrecognized disease or defect by applying tests, examinations, or other procedures in a population",
  "Screening test ≠ Diagnostic test: Screen-positive cases require diagnostic workup to confirm disease",
  "TYPES: Mass screening, Selective/High-risk screening, Multiphasic screening, Opportunistic screening",
  "WILSON & JUNGNER CRITERIA (WHO, 1968) for a valid screening programme:",
  "  → Disease should be an important health problem with known natural history",
  "  → Acceptable, safe, and precise test available",
  "  → Effective and accepted treatment for disease at early stage",
  "  → Facilities for diagnosis and treatment available",
  "  → Detectable early latent or presymptomatic stage",
  "  → Cost-benefit in favour of screening programme; continuous process",
], { fontSize: 12.5 });

contentSlide(pres, "Screening Test Evaluation: Validity & Reliability", [
  "VALIDITY: Ability of a test to accurately classify individuals. Two components:",
  "  → SENSITIVITY: True positive rate = TP / (TP+FN) × 100. Ability to detect true cases. Minimizes false negatives",
  "  → SPECIFICITY: True negative rate = TN / (TN+FP) × 100. Ability to exclude true non-cases. Minimizes false positives",
  "  → Sensitivity and Specificity have inverse relationship; determined by the cut-off point",
  "PREDICTIVE VALUES (affected by prevalence):",
  "  → Positive Predictive Value (PPV): TP / (TP+FP) – increases with higher prevalence",
  "  → Negative Predictive Value (NPV): TN / (TN+FN) – decreases with higher prevalence",
  "RELIABILITY: Reproducibility; consistency of results (measured by Kappa coefficient for agreement)",
  "ROC CURVE: Graphical plot of Sensitivity vs 1-Specificity at various cut-off points; AUC measures overall accuracy",
], { fontSize: 12.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 10 – BIAS, CONFOUNDING, SURVEILLANCE
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 10", "Bias, Confounding & Surveillance");

twoColSlide(pres, "Bias in Epidemiological Studies",
  "SELECTION BIAS",
  [
    "Systematic error in selection of study subjects",
    "Berkson's bias: Hospital controls over-represent disease → spurious negative association",
    "Neyman (Prevalence-Incidence) bias: Only survivors enrolled in retrospective study",
    "Healthy worker effect: Workers healthier than general population",
    "Non-response bias: Non-responders differ from responders",
    "Prevention: Proper sampling; RCT; define eligibility criteria clearly",
  ],
  "INFORMATION BIAS",
  [
    "Systematic error in measurement/classification of exposure or outcome",
    "Recall bias: Cases recall exposure better than controls (case-control studies)",
    "Observer/Interviewer bias: Differential probing between cases and controls",
    "Hawthorne effect: Subjects change behavior when observed",
    "Misclassification: Non-differential (dilutes association toward null); Differential (biases in any direction)",
    "Prevention: Blind data collection; standardized protocols; validated instruments",
  ],
  C.accent4, C.accent3
);

contentSlide(pres, "Confounding & Effect Modification", [
  "CONFOUNDING: A confounder is a variable that is: (1) associated with exposure, (2) associated with outcome independent of exposure, (3) NOT an intermediate in causal pathway",
  "  → Example: Alcohol and lung cancer – smoking is a confounder (smokers drink more AND smoking causes lung cancer)",
  "Control at design stage: Randomization (best); Restriction; Matching",
  "Control at analysis stage: Stratification (Mantel-Haenszel); Multivariable regression; Propensity score analysis",
  "EFFECT MODIFICATION (Interaction): The effect of exposure on outcome differs across levels of a third variable (modifier)",
  "  → Not a bias – it is a real biological phenomenon and should be reported, not controlled",
  "  → Example: Aspirin use reduces MI more in men than in women",
], { fontSize: 13 });

contentSlide(pres, "Epidemiological Surveillance", [
  "DEFINITION: 'The ongoing systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice' (CDC/Thacker)",
  "PURPOSE: Monitor disease trends; detect outbreaks; evaluate interventions; resource allocation",
  "TYPES: (a) Passive surveillance: Routine notification from health facilities (under-reports); (b) Active surveillance: Proactive data collection by health authorities; (c) Sentinel surveillance: Selected reporting sites",
  "COMPONENTS: Data collection → Analysis → Interpretation → Dissemination → Action",
  "NOTIFIABLE DISEASES: Compulsory notification – cholera, plague, yellow fever (International Health Regulations); and national list",
  "SPECIAL SYSTEMS: IDSP (Integrated Disease Surveillance Programme, India); WHO EWARN; HMIS",
  "Epi-Info, DHIS2: Software tools used for surveillance data management",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 11 – INFECTIOUS DISEASE EPIDEMIOLOGY
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 11", "Infectious Disease Epidemiology");

contentSlide(pres, "Chain of Infection", [
  "Infectious disease requires an unbroken chain: Infectious Agent → Reservoir → Portal of exit → Route of transmission → Portal of entry → Susceptible host",
  "RESERVOIR: The natural habitat of an infectious agent. Types: Human (anthroponosis), Animal (zoonosis), Environment (soil, water)",
  "PORTAL OF EXIT: Route by which agent leaves reservoir – respiratory tract (cough), GI tract (stool), skin/lesions, blood, placenta",
  "ROUTES OF TRANSMISSION: Direct contact; indirect contact (fomites); airborne (droplet nuclei); vector-borne; vehicle-borne (food, water)",
  "PORTAL OF ENTRY: Respiratory tract, GI tract, mucous membranes, skin (intact or broken), placenta",
  "SUSCEPTIBLE HOST: Determined by immunity (innate + acquired), nutritional status, age, genetic factors",
  "Breaking the chain: Targeting any link effectively prevents/controls disease",
], { fontSize: 13.5 });

contentSlide(pres, "Key Epidemiological Concepts in Infectious Diseases", [
  "INFECTION: Entry, development or multiplication of infectious agent in a host; not always causes illness",
  "INCUBATION PERIOD: Interval between infection and onset of clinical signs (important for source tracing & quarantine)",
  "COMMUNICABILITY: Ability to spread from infected to susceptible host. Measured by: Serial interval; Generation time",
  "HERD IMMUNITY: Indirect protection to unimmunized when a sufficient proportion of population is immune. Threshold varies (e.g., ~95% for measles)",
  "EPIDEMIC THRESHOLD / Ro (Basic Reproduction Number): Average number of secondary cases from one primary case in a fully susceptible population",
  "  → Ro >1: Epidemic spreads; Ro =1: Endemic; Ro <1: Epidemic dies out",
  "CARRIER: Infected person who harbors agent without clinical symptoms but can transmit to others. Types: Healthy, incubatory, convalescent, chronic",
], { fontSize: 13 });

contentSlide(pres, "Epidemic Investigation (Steps)", [
  "1. Establish existence of epidemic: Compare current with expected (baseline) case count",
  "2. Verify the diagnosis: Clinical & laboratory confirmation",
  "3. Define and identify cases: Develop case definition (clinical criteria + person, place, time)",
  "4. Describe the epidemic: Construct epidemic curve; map cases by place; analyze by person",
  "5. Formulate hypothesis: Based on descriptive data – identify probable source and mode of transmission",
  "6. Test hypothesis: Conduct case-control or cohort study; calculate attack rates",
  "7. Control measures: Implement immediately (even before hypothesis confirmed if public health threat is high)",
  "8. Communication: Notify authorities; report findings; recommend preventive actions",
  "EPIDEMIC CURVE shapes: Point source (sharp rise, short duration); propagated (successive waves); mixed",
], { fontSize: 12.5 });

contentSlide(pres, "Types of Epidemics & Control Measures", [
  "TYPES BY SOURCE: (a) Common-source (point, intermittent, continuous) – from single contaminated source; (b) Propagated/Host-to-host – person-to-person spread; (c) Mixed",
  "CONTROL MEASURES IN INFECTIOUS DISEASES:",
  "  → Isolation: Separation of infected persons to prevent spread",
  "  → Quarantine: Restriction of movement of contacts during maximum incubation period",
  "  → Contact tracing: Identify and manage contacts",
  "  → Immunization: Active (vaccines) or Passive (immunoglobulins)",
  "  → Chemoprophylaxis: Preventive drug treatment (e.g., INH for TB contacts)",
  "  → Vector control: IRS, bed nets, larval control",
  "  → Environmental sanitation: Safe water, sanitation, food hygiene",
], { fontSize: 13 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SECTION 12 – ADVANCED TOPICS
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
sectionSlide(pres, "SECTION 12", "Advanced Topics & Quick Reference");

contentSlide(pres, "Systematic Reviews & Meta-Analysis", [
  "SYSTEMATIC REVIEW: Rigorous, structured synthesis of all available evidence on a focused research question",
  "  → Follows PRISMA guidelines; uses pre-registered protocol (PROSPERO)",
  "  → Steps: Define question (PICO) → Search → Screen → Extract → Assess quality → Synthesize",
  "META-ANALYSIS: Statistical combination of results from multiple studies",
  "  → Produces a pooled estimate (Forest plot); quantifies heterogeneity (I² statistic)",
  "  → I² >75%: High heterogeneity; consider not pooling; use random-effects model",
  "  → Funnel plot: Detects publication bias (asymmetry = possible bias)",
  "  → Fixed-effects model: Assumes one true effect size; Random-effects model: Allows for between-study variation",
  "Cochrane Collaboration: Gold standard source for systematic reviews in healthcare",
], { fontSize: 13 });

contentSlide(pres, "Sensitivity & Specificity – Worked Example", [
  "Test A applied to 1000 people (200 have disease, 800 do not):",
  "  True Positives (TP) = 180 | False Negatives (FN) = 20 | False Positives (FP) = 40 | True Negatives (TN) = 760",
  "SENSITIVITY = TP/(TP+FN) = 180/200 = 90% → Test detects 90% of true cases",
  "SPECIFICITY = TN/(TN+FP) = 760/800 = 95% → Test correctly excludes 95% of non-cases",
  "PPV = TP/(TP+FP) = 180/220 = 81.8% → If test positive, 81.8% truly have disease",
  "NPV = TN/(TN+FN) = 760/780 = 97.4% → If test negative, 97.4% truly do not have disease",
  "Snout (SN-out): High SENSITIVITY rules OUT disease (good for screening)",
  "Spin (SP-in): High SPECIFICITY rules IN disease (good for confirmation)",
  "Likelihood Ratio Positive (LR+) = Sensitivity / (1-Specificity); LR- = (1-Sensitivity) / Specificity",
], { fontSize: 13 });

contentSlide(pres, "Important Definitions Quick Reference", [
  "Incubation period: Time between exposure and symptom onset",
  "Endemic: Usual constant presence of disease in a given community or geographic area",
  "Epidemic: Occurrence clearly in excess of normal expectancy; community-wide",
  "Pandemic: Epidemic that has spread to multiple countries or continents",
  "Herd immunity threshold: (1 – 1/Ro) × 100 %",
  "Attack rate: Proportion of exposed persons who develop disease",
  "CFR (Case Fatality Rate): Proportion of cases who die; measures disease severity",
  "Zoonosis: Infections transmissible from vertebrate animals to humans (e.g., rabies, brucellosis, Nipah)",
  "Fomite: Inanimate objects that carry infection",
  "Iatrogenic: Disease caused by medical treatment/intervention",
], { fontSize: 13.5 });

// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
// SUMMARY / CLOSING SLIDE
// ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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    "Epidemiology is the quantitative study of disease distribution and determinants in populations",
    "Epidemiological Triad (Agent-Host-Environment) + Time form the basis of disease causation",
    "Natural history and Levels of Prevention (Leavell & Clark) are foundational frameworks",
    "Incidence, Prevalence, and mortality measures are the essential tools of epidemiological quantification",
    "Study designs range from descriptive to analytical to experimental – each with specific strengths and limitations",
    "Bradford Hill's 9 criteria guide causal inference from epidemiological association",
    "Bias, confounding, and chance must always be excluded before claiming causation",
    "Screening programmes require high sensitivity; treatment must be effective at early stage",
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// ─── WRITE FILE ─────────────────────────────────────────────────────────────
pres.writeFile({ fileName: "/home/daytona/workspace/epidemiology-ppt/Epidemiology_CFM_PostGrad.pptx" })
  .then(() => console.log("SUCCESS: /home/daytona/workspace/epidemiology-ppt/Epidemiology_CFM_PostGrad.pptx"))
  .catch(err => { console.error("ERROR:", err); process.exit(1); });

cd /home/daytona/workspace/epidemiology-ppt && node epidemiology_ppt.js

ls -lh /home/daytona/workspace/epidemiology-ppt/Epidemiology_CFM_PostGrad.pptx &…

python -m markitdown /home/daytona/workspace/epidemiology-ppt/Epidemiology_CFM_P…

python3 -c " from pptx import Presentation prs = Presentation('/home/daytona/wor…

node -e " const pptxgen = require('pptxgenjs'); // Verify the file exists and is…

libreoffice --headless --convert-to pdf /home/daytona/workspace/epidemiology-ppt…

cp /home/daytona/workspace/epidemiology-ppt/Epidemiology_CFM_PostGrad.pptx /tmp/…

cp /tmp/Epidemiology_CFM_PostGrad.pdf /home/daytona/workspace/epidemiology-ppt/E…