Preventive and Social Medicine (PSM / Epidemiology) Epidemiology: Cohort vs Case-control vs Cross-sectional RCTs (Randomized Controlled Trials) Sensitivity vs Specificity vs PPV/NPV Incidence vs Prevalence Levels of prevention SEPSE/MEPSE/PE graphs Important scientists & discoveries Immunization: Vaccine types + live/killed vaccines National Immunization Schedule Rabies vaccine schedule HPV strains Vaccine Vial Monitor (VVM) Cold chain equipment Open vial policy Mission Indradhanush Maternal & Child Health: IMR, MMR, U5MR, NNMR, PNMR (Health Indices) Birth weight & MUAC (Mid-Upper Arm Circumference) Breastfeeding ASHA/ANM visits ICDS & Mid-day meal programme Anemia Mukt Bharat Family Planning & Demography: Pearl Index & Couple Protection Rate OCPs, IUCDs, Depo No-scalpel vasectomy Demographic cycle TFR, NRR, GRR, GFR Population pyramids Biostatistics: Parametric vs Non-parametric tests Mean/Median/Mode Statistical errors Distribution curves Graphs & charts Random sampling methods Environment & Vectors: Mosquito differences (Anopheles/Culex/Aedes) Sandfly & Rat flea Air pollution index Water purification apparatus Biomedical waste color coding National Health Programmes: NTEP / DOTS / Nikshay NACP, NVBDCP, NLEP, IDSP, PMJAY National health schemes Health System & Committees: SC vs PHC vs CHC (Sub Center, Primary, Community Health Center) Population norms Grassroot workers Bhore, Mudaliar, Srivastava, Kartar Singh committees Communicable Diseases: Incubation periods ORS TB / Leprosy protocols Important vectors in India Extra High-Yield: Disaster management & triage Occupational diseases Family cycle Bioterrorism categories Mental health & suicide indicators WHO, UNICEF, SDGs
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I have confirmed the Park's content. Now I'll produce the complete, comprehensive PSM high-yield notes covering every topic in the syllabus.
PSM / Community Medicine - Complete High-Yield Notes
Based on Park's Textbook of Preventive and Social Medicine
SECTION 1: EPIDEMIOLOGY
Study Designs Comparison
| Feature | Cohort | Case-Control | Cross-Sectional |
|---|---|---|---|
| Direction | Forward (prospective) | Backward (retrospective) | Snapshot (one time) |
| Starts with | Exposure | Disease (cases + controls) | Population sample |
| Best for | Incidence, RR, AR | Rare diseases, OR | Prevalence |
| Measure | Relative Risk (RR) | Odds Ratio (OR) | Prevalence ratio |
| Time | Long, expensive | Short, cheap | Short, cheap |
| Bias risk | Loss to follow-up | Recall bias, selection bias | Prevalence-incidence bias |
| Example | Framingham Heart Study | Doll & Hill (smoking-lung cancer) | NFHS surveys |
Key formulas:
- Relative Risk (RR) = Incidence in exposed / Incidence in unexposed
- Odds Ratio (OR) = (a×d) / (b×c) from 2×2 table
- Attributable Risk (AR) = Incidence exposed - Incidence unexposed
- Population Attributable Risk % = (Ie - Iu)/Ie × 100
When OR ≈ RR: When disease is rare (<10% prevalence)
Randomized Controlled Trials (RCTs)
- Gold standard of epidemiological studies
- Randomization eliminates confounding
- Blinding: Single (patient), Double (patient+investigator), Triple (+ statistician)
- Placebo effect controlled by control arm
- Intention to treat analysis: analyze in group assigned, not treated
- Per protocol analysis: only those who completed protocol
- Phase I-IV trials:
- Phase I: Safety, dose-finding (healthy volunteers, ~20-80)
- Phase II: Efficacy + safety (patients, ~100-300)
- Phase III: Large-scale efficacy vs standard (1000s, RCT)
- Phase IV: Post-marketing surveillance
Sensitivity, Specificity, PPV, NPV
2×2 Table:
| Disease + | Disease - | |
|---|---|---|
| Test + | a (TP) | b (FP) |
| Test - | c (FN) | d (TN) |
- Sensitivity = a/(a+c) = TP/(TP+FN) → Detects true positives ("SnNout" - Sensitive test, Negative = rule OUT)
- Specificity = d/(b+d) = TN/(TN+FP) → Avoids false positives ("SpPin" - Specific test, Positive = rule IN)
- PPV = a/(a+b) → Increases with higher prevalence
- NPV = d/(c+d) → Decreases with higher prevalence
- Likelihood Ratio + = Sensitivity/(1-Specificity)
- Likelihood Ratio - = (1-Sensitivity)/Specificity
Key points:
- Sensitivity & Specificity are fixed properties of the test (independent of prevalence)
- PPV & NPV depend on prevalence of disease
- Screening tests require high sensitivity (don't miss cases)
- Confirmatory/diagnostic tests require high specificity (avoid false positives)
Incidence vs Prevalence
| Incidence | Prevalence | |
|---|---|---|
| Definition | New cases in a time period | All cases (new + old) at a point/period |
| Denominator | Population at risk | Total population |
| Measures | Risk of getting disease | Disease burden |
| Affected by | Duration of disease | Incidence + duration |
| Types | - | Point prevalence, Period prevalence |
Relationship: Prevalence = Incidence × Duration (P ≈ I × D), valid when disease is in equilibrium and prevalence is low (<10%)
Incidence types:
- Incidence rate (force of morbidity): uses person-years in denominator
- Attack rate: for outbreaks, epidemic (% affected in defined group)
- Secondary attack rate: new cases among contacts of primary case
Levels of Prevention
| Level | Target | Timing | Examples |
|---|---|---|---|
| Primordial | Risk factor emergence | Before risk factors appear | Health promotion, lifestyle education |
| Primary | Before disease onset | Pre-pathogenesis phase | Immunization, health education, chemoprophylaxis |
| Secondary | Early disease | Pathogenesis (pre-symptomatic) | Screening, early diagnosis + treatment |
| Tertiary | Established disease | Late pathogenesis | Rehabilitation, disability limitation |
Park's key principle: Natural history of disease is the basis for levels of prevention.
Modes of intervention (Primary prevention):
- Health promotion
- Specific protection (immunization, chemoprophylaxis)
SEPSE / MEPSE / PE Graphs (Epidemic Curves)
- Common source epidemic (point source): Rapid rise, rapid fall; bell-shaped; incubation period = interval from exposure to peak
- Propagated (person-to-person): Multiple peaks; successive waves separated by incubation period
- Mixed epidemic: Features of both
Semi-log graphs: Used to show rates of change over time - a straight line indicates constant rate of change
Important Scientists & Discoveries
| Scientist | Discovery/Contribution |
|---|---|
| John Snow | Father of Epidemiology - Broad St. pump, cholera outbreak 1854 |
| Edward Jenner | Smallpox vaccination (1796) |
| Louis Pasteur | Germ theory, vaccines (rabies, anthrax) |
| Robert Koch | Koch's postulates, TB bacillus, cholera vibrio |
| Joseph Lister | Antiseptic surgery |
| William Farr | Vital statistics, standardized mortality |
| Semmelweis | Hand washing, puerperal fever |
| Fleming | Penicillin (1928) |
| Doll & Hill | Smoking - lung cancer (1950, case-control) |
| James Lind | Scurvy - citrus fruits (1747) |
| Goldberger | Pellagra - niacin deficiency |
SECTION 2: IMMUNIZATION
Vaccine Types
| Type | Examples | Key Features |
|---|---|---|
| Live attenuated | BCG, OPV, MMR, Varicella, Yellow fever, Typhoid (oral Ty21a), Rotavirus | Single dose often sufficient; lifelong immunity; CI in immunocompromised |
| Killed/Inactivated | IPV (Salk), Hepatitis A, Rabies (PCECV), Pertussis (whole cell), Cholera (killed oral) | Multiple doses needed; booster required; safe in immunocompromised |
| Toxoid | Tetanus, Diphtheria | Modified toxin; long-lasting immunity with boosters |
| Subunit/Recombinant | Hepatitis B, HPV, Acellular pertussis (DTaP) | Highly purified, safe |
| Polysaccharide | Meningococcal (plain), Pneumococcal (plain), Typhoid (Vi) | No T-cell response; not effective <2 years |
| Conjugate | Hib, PCV, MenC | Polysaccharide + protein carrier; T-cell response; effective in infants |
| mRNA | COVID-19 (Pfizer, Moderna) | New platform |
National Immunization Schedule (India - UIP)
| Age | Vaccines |
|---|---|
| Birth | BCG, OPV-0 (birth dose), Hepatitis B (birth dose) |
| 6 weeks | OPV-1, Pentavalent-1 (DPT+HepB+Hib), IPV-1, Rotavirus-1, PCV-1 |
| 10 weeks | OPV-2, Pentavalent-2, IPV-2, Rotavirus-2, PCV-2 |
| 14 weeks | OPV-3, Pentavalent-3, IPV-3, Rotavirus-3, PCV-3 |
| 9-12 months | Measles-Rubella (MR-1), JE-1 (endemic districts), Vitamin A (1st dose) |
| 16-24 months | DPT booster-1, OPV booster, MR-2, JE-2, Vitamin A (2nd dose) |
| 5-6 years | DPT booster-2 |
| 10 years | TT |
| 16 years | TT |
| Pregnancy | TT-1, TT-2 (or TT booster if previously immunized) |
Key additions: PCV (Pneumococcal Conjugate Vaccine), Rotavirus, IPV - added to UIP in 2014-2017
Td replaces TT in adults in recent NIS updates
Rabies Vaccine Schedule
Pre-exposure prophylaxis (PrEP):
- 3 doses: Days 0, 7, 28
- Booster: Every 2 years for high-risk groups (veterinarians, lab workers)
Post-exposure prophylaxis (PEP):
| Category | Wound Type | Management |
|---|---|---|
| I | Touching/feeding animal, licks on intact skin | Wash, no vaccine |
| II | Nibbling uncovered skin, minor scratches without bleeding | Wound treatment + vaccine |
| III | Single/multiple transdermal bites, contamination of mucosa | Wound treatment + vaccine + RIG |
PEP vaccine schedule (Essen regimen): Days 0, 3, 7, 14, 28 (5 doses IM)
Zagreb (2-1-1) regimen: Days 0 (2 doses in both deltoids), Day 7 (1 dose), Day 21 (1 dose) - 4 doses total
RIG (Rabies Immunoglobulin): 20 IU/kg (human) or 40 IU/kg (equine) - infiltrate wound, remainder IM
HPV Strains
- HPV 16 & 18: Cervical cancer (70% of cases), oropharyngeal cancer, anal cancer
- HPV 6 & 11: Genital warts (condylomata acuminata), recurrent respiratory papillomatosis
- Bivalent vaccine (Cervarix): Types 16, 18
- Quadrivalent vaccine (Gardasil): Types 6, 11, 16, 18
- 9-valent vaccine (Gardasil 9): Types 6, 11, 16, 18, 31, 33, 45, 52, 58
- India's Cervavac: Quadrivalent (domestic HPV vaccine)
- Schedule: 2 doses if <15 years (0, 6 months); 3 doses if ≥15 years (0, 1-2, 6 months)
- UIP India: HPV vaccine added for girls 9-14 years in 2023
Vaccine Vial Monitor (VVM)
- Attached to each vaccine vial
- Contains heat-sensitive material (inner square + outer circle)
- Reading: If inner square is LIGHTER than outer circle → vaccine usable; if SAME or DARKER → discard
- Monitors cumulative heat exposure (not cold)
- VVM does NOT replace cold chain - it only indicates if vaccine has been overheated
- VVM stages: 1 (usable), 2 (usable), 3 (discard), 4 (discard)
Cold Chain Equipment
| Storage Point | Equipment | Temperature |
|---|---|---|
| National/State store | Cold room (walk-in cooler) | +2°C to +8°C |
| Regional/District store | ILR (Ice Lined Refrigerator), Deep Freezer | ILR: +2 to +8°C; DF: -15 to -25°C |
| PHC/CHC | ILR, Deep Freezer | Same as above |
| Sub-center/Outreach | Vaccine Carrier, Cold box | +2°C to +8°C |
Key equipment:
- ILR (Ice Lined Refrigerator): Stores vaccines at +2-8°C; used for OPV, DPT, Hepatitis B, BCG
- Deep Freezer: Stores OPV at -15 to -25°C, makes ice packs
- Cold box: Transport over long distances, 24-72 hours
- Vaccine carrier: Field transport, 4 ice packs, 4-6 hours
Freeze-sensitive vaccines (must NOT freeze): DPT, TT, DT, Hepatitis B, Hib, IPV, PCV - these are damaged by freezing
Freeze-tolerant (can be stored frozen): OPV, BCG, Measles, MMR, Yellow fever
Open Vial Policy
Allows multi-dose vials to be used in subsequent sessions (not discarded after opening) for:
- DPT, TT, DT, Hepatitis B, Hib, OPV - if: stored at 2-8°C, cold chain maintained, VVM not reached discard point, not expired, sterile technique used
- NOT applicable to: BCG (must be used within 4 hours), measles/rubella, JE - single-session use
Mission Indradhanush
- Launched: December 2014 (full launch)
- Aim: Achieve >90% full immunization coverage in districts with lowest coverage
- Target: Children <2 years and pregnant women
- Intensive Mission Indradhanush (IMI): 2017-2018, IMI 2.0 (2019-2020), IMI 3.0 (2021)
- Districts targeted: Initially 201 high-risk districts, then expanded
- 7 vaccines initially: BCG, DPT, OPV, Measles, TT, Hepatitis B + additional vaccines
- Har Ghar Dastak: Door-to-door mobilization component
SECTION 3: MATERNAL & CHILD HEALTH
Health Indices (Definitions & Current Values)
| Index | Definition | India Value (approx) |
|---|---|---|
| IMR (Infant Mortality Rate) | Deaths <1 year per 1000 live births | ~28 (SRS 2020) |
| NNMR (Neonatal Mortality Rate) | Deaths in first 28 days per 1000 live births | ~20 |
| PNMR (Post-Neonatal MR) | Deaths 28 days-1 year per 1000 live births | IMR - NNMR |
| U5MR (Under-5 MR) | Deaths <5 years per 1000 live births | ~32 (SRS 2020) |
| MMR (Maternal Mortality Ratio) | Maternal deaths per 100,000 live births | ~97 (SRS 2018-20) |
| Perinatal MR | Stillbirths + deaths <7 days per 1000 total births | - |
| Stillbirth rate | Fetal deaths ≥28 weeks per 1000 total births | - |
Causes of IMR: Neonatal causes (70%)- birth asphyxia, prematurity, sepsis; Post-neonatal - diarrhea, pneumonia
Best indicator of MCH services: IMR
Best indicator of overall community health: Life expectancy at birth
Birth Weight & MUAC
Low Birth Weight (LBW): <2500 g
- Preterm: <37 weeks gestation
- SGA (Small for Gestational Age): <10th percentile
- VLBW: <1500 g; ELBW: <1000 g
Normal birth weight: 2.5-3.5 kg; Mean = 2.9 kg (India), 3.2 kg (Western)
MUAC (Mid-Upper Arm Circumference):
- Measured at mid-point between olecranon and acromion
- Children 6-59 months:
- Green (≥12.5 cm): Normal
- Yellow (11.5-12.4 cm): MAM (Moderate Acute Malnutrition)
- Red (<11.5 cm): SAM (Severe Acute Malnutrition)
- Adults (men): <23 cm = undernutrition
- Pregnant women: <21 cm = at risk
Breastfeeding
- Colostrum: First 2-3 days; rich in IgA, proteins, Vitamin A, leukocytes; acts as "first vaccine"
- Exclusive breastfeeding: Birth to 6 months (no water, no other food)
- Complementary feeding: Starts at 6 months; breastfeeding continues till 2 years or beyond
- Benefits: Passive immunity (IgA), bonding, reduces SIDS, reduces childhood obesity, reduces diarrhea/ARI
WHO Baby-Friendly Hospital Initiative (BFHI): "Ten Steps to Successful Breastfeeding"
Lactation amenorrhea: 98% effective if <6 months postpartum, exclusive breastfeeding, amenorrheic
ASHA / ANM Visits
ASHA (Accredited Social Health Activist):
- Village level (1 per 1000 population in most areas)
- Home visits for newborn care: Days 1, 3, 7, 14, 28, 42
- Facility-based delivery promotion (JSY incentive)
ANM (Auxiliary Nurse Midwife):
- Sub-center level (1 per 5000 population plain, 3000 hilly)
- ANC visits schedule: Minimum 4 visits (now recommended minimum 8 by WHO)
- 1st: <12 weeks (book, weight, BP, Hb, TT)
- 2nd: 14-26 weeks
- 3rd: 28-34 weeks
- 4th: >36 weeks
ICDS & Mid-Day Meal Programme
ICDS (Integrated Child Development Services):
- Launched: 1975 (October 2, Gandhi Jayanti)
- Target: Children <6 years, pregnant/lactating mothers, adolescent girls
- Services (6): Supplementary nutrition, immunization, health check-up, referral, pre-school education, nutrition/health education
- Delivered through: Anganwadi centre (1 per 400-800 population)
- Anganwadi Worker (AWW): 1 per centre
- Calories given: 500 kcal + 12-15 g protein (children 6 months - 6 years); 600 kcal for severely malnourished
Mid-Day Meal (MDM) / PM POSHAN:
- Launched: 1995 (National Programme of Nutritional Support to Primary Education)
- Renamed PM POSHAN in 2021
- Target: Classes I-VIII in government/government-aided schools
- Also covers pre-primary (Bal Vatika)
- Calories: 450 kcal + 12g protein (Classes I-V); 700 kcal + 20g protein (Classes VI-VIII)
Anemia Mukt Bharat
- Launched: 2018 under POSHAN Abhiyan
- Target: Reduce anemia prevalence by 3 percentage points per year
- 6×6×6 strategy:
- 6 beneficiary groups: Children 6-59 months, 5-9 years, 10-19 years adolescents, pregnant women, lactating mothers, women of reproductive age
- 6 interventions: Prophylactic iron supplementation, deworming, testing, treating, behavior change communication, addressing non-nutritional causes
- 6 institutional mechanisms
SECTION 4: FAMILY PLANNING & DEMOGRAPHY
Pearl Index & Couple Protection Rate
Pearl Index = (Number of accidental pregnancies × 1200) / (Total months of exposure)
- Lower Pearl Index = more effective method
- Condom: 2-15; OCP: 0.1-3; Copper IUD: 0.6-0.8; Tubectomy: 0.5; Vasectomy: 0.1
Couple Protection Rate (CPR):
- % of eligible couples (wife 15-44 years) using any contraception
- India target: 65%+
Contraceptive Methods
OCPs (Oral Contraceptive Pills):
- Combined OCP: Estrogen + Progestin; mechanism = inhibit ovulation (primarily)
- Progestin-only pill (POP/Mini-pill): Thickens cervical mucus; used in lactating women
- Emergency contraception (I-pill): 1.5 mg levonorgestrel within 72 hours (or 2 doses 0.75 mg)
- Contraindications: DVT history, liver disease, smokers >35 years, migraine with aura, breast cancer
IUCD:
- Cu-T 380A: 10 years; Copper IUD; highest effectiveness
- Cu-T 200B: 3 years
- Multiload 375: 5 years
- Mirena (LNG-IUS): 5 years; levonorgestrel-releasing
- Mechanism: Spermicidal (copper ions), prevents implantation
- Inserted within 48 hours of delivery (interval IUCD) or within 12 minutes of placental expulsion (PPIUCD)
Depo-Provera (DMPA):
- 150 mg medroxyprogesterone acetate IM every 3 months
- Mechanism: Inhibits ovulation, thickens cervical mucus
- Return to fertility delayed 6-12 months after discontinuation
No-Scalpel Vasectomy (NSV)
- Introduced in India: 1992
- Technique: Small puncture with special forceps (no scalpel), vas deferens identified and occluded
- Advantages over conventional: Less bleeding, infection, hematoma; faster recovery
- Effective after 20 ejaculations or 3 months (semen analysis to confirm azoospermia)
- Failure rate: 0.1/100 woman-years (Pearl Index 0.1)
- Not immediately effective - not a method of emergency contraception
Demographic Cycle (Demographic Transition Theory)
| Stage | Birth Rate | Death Rate | Population Growth | Countries |
|---|---|---|---|---|
| Stage I (High stationary) | High | High | Stable/low growth | Pre-industrial, primitive |
| Stage II (Early expanding) | High | Falling | Rapid increase | Developing (early) |
| Stage III (Late expanding) | Falling | Low | Still increasing | Developing (late) |
| Stage IV (Low stationary) | Low | Low | Stable | Developed |
| Stage V (Declining) | Very low | Slightly rising | Negative growth | Japan, Germany |
India: Transitioning from Stage II to Stage III
Fertility Rates
| Rate | Formula | India Value |
|---|---|---|
| GFR (General Fertility Rate) | Births per 1000 women aged 15-44/49 years | ~66 |
| TFR (Total Fertility Rate) | Average children per woman in reproductive life | ~2.0 (NFHS-5) |
| GRR (Gross Reproduction Rate) | Daughters born per woman (ignores mortality) | - |
| NRR (Net Reproduction Rate) | Daughters surviving to reproductive age per woman | NRR=1 → replacement level |
Replacement level TFR: 2.1 (to account for female deficit at birth and childhood mortality)
India NRR: Reached ~1 - indicating approaching population stabilization
Population Pyramids
- Expansive (broad base): High birth rate, high death rate, high growth - developing countries
- Constrictive (narrow base): Low birth rate, low death rate - developed countries
- Stationary (columnar): Stable population - Sweden type
SECTION 5: BIOSTATISTICS
Parametric vs Non-Parametric Tests
| Feature | Parametric | Non-Parametric |
|---|---|---|
| Assumption | Normal distribution | No distribution assumption |
| Data type | Continuous (interval/ratio) | Ordinal or non-normal |
| Examples | t-test, ANOVA, Pearson's r | Mann-Whitney U, Kruskal-Wallis, Spearman's rho, Chi-square |
| Comparison | Parametric | Non-Parametric |
|---|---|---|
| 2 independent groups | Independent t-test | Mann-Whitney U test |
| 2 paired groups | Paired t-test | Wilcoxon signed-rank |
| >2 groups | ANOVA (one-way) | Kruskal-Wallis |
| Correlation | Pearson's r | Spearman's rho |
| Categorical | - | Chi-square, Fisher's exact |
Mean / Median / Mode
- Mean: Sum/n; affected by outliers; best for symmetric distribution
- Median: Middle value; not affected by outliers; best for skewed distribution
- Mode: Most frequent value; can be used for any data type
- Positively skewed: Mean > Median > Mode (tail on right)
- Negatively skewed: Mean < Median < Mode (tail on left)
- Normal distribution: Mean = Median = Mode
Statistical Errors
| H₀ True | H₀ False | |
|---|---|---|
| Accept H₀ | Correct (1-α) | Type II error (β) |
| Reject H₀ | Type I error (α) | Correct (Power = 1-β) |
- Type I error (α): False positive; reject null when true; p-value = probability of Type I error
- Type II error (β): False negative; accept null when false
- Power (1-β): Usually set at 80% or 90%
- p-value: Probability of obtaining results as extreme as observed, assuming H₀ is true; typically p<0.05 is significant
Distribution Curves
- Normal (Gaussian): Bell-shaped, symmetric; Mean±1SD = 68.2%; ±2SD = 95.4%; ±3SD = 99.7%
- Poisson: For rare events (counts); used for disease incidence in small populations
- Binomial: For dichotomous outcomes in fixed number of trials
- Skewed distributions: Positive skew (right tail), Negative skew (left tail)
- Standard Normal (Z-distribution): Mean=0, SD=1
Graphs & Charts
| Type | Use |
|---|---|
| Bar chart | Discrete/categorical data comparison |
| Histogram | Continuous data frequency distribution |
| Frequency polygon | Same as histogram but as line |
| Pie chart | Proportions of a whole |
| Line graph | Trends over time |
| Scatter plot | Correlation between two variables |
| Box plot | Distribution summary (median, quartiles, outliers) |
| Epidemic curve | Disease cases over time in an outbreak |
| Lorenz curve | Income inequality |
Random Sampling Methods
| Method | Description | Example |
|---|---|---|
| Simple Random | Every individual has equal chance; lottery/random numbers | Lottery draw |
| Systematic | Every kth individual (k = N/n) | Every 10th patient in OPD |
| Stratified | Divide into strata, random sample from each | By age/sex/district |
| Cluster | Divide into clusters, randomly select clusters | Villages as clusters (EPI survey) |
| Multistage | Combination of methods over stages | NFHS methodology |
Non-probability sampling: Convenience, Purposive, Snowball, Quota - NOT representative
SECTION 6: ENVIRONMENT & VECTORS
Mosquito Differences
| Feature | Anopheles | Culex | Aedes |
|---|---|---|---|
| Resting position | 45° angle to surface | Parallel to surface | Parallel to surface |
| Eggs | Separate, with floats | Rafts (clusters) | Separate (dry/wet) |
| Breeding | Clean, stagnant/slow-moving water | Polluted water, drains | Clean, collected water (tires, pots) |
| Biting time | Dawn/dusk/night | Night | Daytime (Aedes aegypti) |
| Disease | Malaria, Filariasis (some) | Filariasis, JE, West Nile | Dengue, Chikungunya, Zika, Yellow fever |
| Larval position | Parallel to water surface | Hangs at angle | Hangs at angle |
Anopheles for malaria: A. culicifacies (main), A. stephensi (urban), A. fluviatilis, A. minimus, A. dirus (Northeast India)
Culex quinquefasciatus: Main vector of Filariasis and Japanese Encephalitis (JE also by C. tritaeniorhynchus in rural areas)
Sandfly & Rat Flea
Sandfly (Phlebotomus):
- Vector for: Leishmaniasis (Kala-azar) - P. argentipes in India; Sandfly fever; Bartonellosis
- Features: Hairy, small (1-3mm), weak flier, no hum, bites at night
- Breeding: Moist organic debris (cracks in walls, animal burrows)
- Control: DDT spraying; insect repellents
Rat Flea (Xenopsylla cheopis):
- Vector for: Plague (Yersinia pestis), Murine typhus (Rickettsia typhi)
- Transmission: Flea bite when rat dies and flea seeks new host
- "Rat flea of rat, flea seeks man when rat dies"
- Control: Rodent control + residual insecticides
Air Pollution Index
NAQI (National Air Quality Index) - India (6 pollutants monitored):
- PM2.5, PM10, NO₂, SO₂, CO, O₃ (and NH₃, Pb)
- Categories: Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400), Severe (401-500)
- PM2.5 (≤2.5 μm): Penetrates deepest into lungs; most harmful
- PM10 (≤10 μm): Reaches bronchi
- Standard: PM2.5 annual mean 40 μg/m³ (India WHO: 5 μg/m³)
Water Purification
| Method | Notes |
|---|---|
| Boiling | Most reliable household method; kills all pathogens |
| Chlorination | Most widely used for municipal supply; 0.5 mg/L residual chlorine at consumer end |
| Chlorination + Coagulation | For turbid water (alum or potash alum) |
| Slow sand filter | Schmutzdecke (biological film); 99.9% bacterial removal |
| Rapid sand filter | Faster; preceded by coagulation; requires back-washing |
| Reverse osmosis | Removes all dissolved salts; for desalination |
| UV radiation | No chemical taste; effective for clear water only |
Horrock's apparatus: Field test for chlorine demand; uses tablets
Chlorometer / Lovibond comparator: Measures residual chlorine
Del Agua kit: Field testing of water quality (portable)
Berkfeld/Chamberland filter: Candle filter; removes bacteria not viruses
Biomedical Waste Color Coding (BMW Rules 2016)
| Color | Container | Waste |
|---|---|---|
| Yellow | Plastic bag/container | Human anatomical waste, animal waste, soiled waste (dressing, plaster), liquid waste |
| Red | Plastic bag/container | Contaminated waste (tubing, gloves, catheters, disposable items excluding sharps) |
| White (Translucent) | Puncture-proof, leak-proof container | Sharps waste (needles, syringes with fixed needles, blades) |
| Blue | Cardboard boxes with blue marking | Glassware, metallic implants |
Treatment:
- Yellow: Incineration or deep burial
- Red: Autoclaving/microwaving then shredding → recycling
- White (sharps): Autoclaving/chemical treatment + shredding/encapsulation
- Blue: Disinfection + disposal in authorized recycler
SECTION 7: NATIONAL HEALTH PROGRAMMES
NTEP (National TB Elimination Programme) / DOTS
- Previously RNTCP (Revised National TB Control Programme)
- Renamed NTEP in 2020; target: TB elimination by 2025 (End TB by 2030 globally)
- DOTS (Directly Observed Treatment Short-course): Cornerstone of NTEP
Treatment regimens (NTEP):
- New cases (DS-TB): 2HRZE/4HR (2 months intensive: Isoniazid+Rifampicin+Pyrazinamide+Ethambutol; 4 months continuation: Isoniazid+Rifampicin)
- Previously treated: DST-guided; empirically 2HRZES/1HRZE/5HRE
- MDR-TB: Longer regimen (Bedaquiline-based)
- Nikshay: IT platform for TB notification; mandatory for all providers
- Nikshay Poshan Yojana: Rs. 500/month to TB patient during treatment
DOTS Plus: For MDR-TB management
Bedaquiline, Delamanid: New drugs for MDR/XDR-TB
NACP (National AIDS Control Programme)
- NACP I: 1992-1999; awareness
- NACP II: 1999-2006; prevention
- NACP III: 2007-2012; halt & reverse epidemic
- NACP IV: 2012-2017
- NACP V: 2021-2025; target 95-95-95 by 2025
- 95% of PLHIV know status
- 95% of those diagnosed on ART
- 95% of those on ART virally suppressed
ICTC (Integrated Counselling and Testing Centre): HIV testing
ART centres: Free ART for all PLHIV
PPTCT (Prevention of Parent-to-Child Transmission): Option B+ (all pregnant HIV+ women on lifelong ART)
Targeted Interventions: For high-risk groups (FSW, MSM, IDU, truckers)
Other National Programmes
| Programme | Key Points |
|---|---|
| NVBDCP (National Vector Borne Disease Control) | Covers malaria, dengue, chikungunya, JE, filariasis, kala-azar, scrub typhus |
| NLEP (National Leprosy Eradication Programme) | MDT (Multidrug therapy); paucibacillary (6 months), multibacillary (12 months); declared elimination (<1/10,000) in 2005 |
| IDSP (Integrated Disease Surveillance Programme) | S (Syndromic), P (Presumptive), L (Laboratory) reporting; weekly epidemiological situation report |
| PMJAY (Pradhan Mantri Jan Arogya Yojana) | Ayushman Bharat; 5 lakh/year health cover per family; secondary + tertiary care; ~50 crore beneficiaries |
| NHM (National Health Mission) | NRHM + NUHM; umbrella programme; 2013 |
| JSSK (Janani Shishu Suraksha Karyakram) | Free services for pregnant women and sick newborns at public facilities |
| JSY (Janani Suraksha Yojana) | Cash incentive for institutional delivery |
SECTION 8: HEALTH SYSTEM & COMMITTEES
SC / PHC / CHC Structure
| Level | Population Norm | Staff | Services |
|---|---|---|---|
| Sub-Centre (SC) | Plains: 5000; Hilly/tribal: 3000 | 1 ANM + 1 Male Health Worker; 1 additional ANM | Basic MCH, first contact care |
| PHC (Primary Health Centre) | Plains: 30,000; Hilly: 20,000 | 1 MO + 14 paramedical staff | OPD, MCH, Immunization, 6 beds |
| CHC (Community Health Centre) | 120,000 (4 PHCs) | 4 specialists (physician, surgeon, gynaecologist, paediatrician) + 21 staff | 30 beds, referral |
| Sub-District/Taluk Hospital | 500,000 - 1 million | - | 100 beds |
| District Hospital | 1-3 million | - | 200-500 beds |
IPHS (Indian Public Health Standards): Standards for each level
3 Tier system: SC → PHC → CHC
Important Committees
| Committee | Year | Key Recommendations |
|---|---|---|
| Bhore Committee | 1946 | "Health Survey & Development Committee"; 3-tier health system; PHC concept; "Social physician"; 1 doctor per 2000 population |
| Mudaliar Committee | 1962 | "Health Survey & Planning Committee"; Strengthening PHCs; quality over quantity; recommended upgradation of PHCs |
| Srivastava Committee | 1975 | "Group on Medical Education & Support Manpower"; Introduced Community Health Worker (CHW); basis for ASHA |
| Kartar Singh Committee | 1974 | Multipurpose Health Workers; merged male/female workers under MPW scheme; basis of sub-centre structure |
| Chadha Committee | 1963 | Malaria eradication |
| Bajaj Committee | 1986 | Health manpower; doctor-patient ratio |
| Shrivastava (HLEG) | 2011 | Universal Health Coverage recommendations |
SECTION 9: COMMUNICABLE DISEASES
Incubation Periods (High-Yield)
| Disease | Incubation Period |
|---|---|
| Cholera | 6 hours - 5 days (usually 2-3 days) |
| Typhoid | 1-3 weeks (usually 14 days) |
| Hepatitis A | 15-50 days (mean 28-30 days) |
| Hepatitis B | 45-180 days (mean 60-90 days) |
| Hepatitis E | 15-60 days (mean 40 days) |
| Measles | 10-14 days |
| Chickenpox | 10-21 days (mean 14-16) |
| Mumps | 14-21 days (mean 18 days) |
| Rubella | 14-21 days (mean 16-18 days) |
| Diphtheria | 2-5 days |
| Pertussis | 7-10 days |
| Plague (bubonic) | 2-7 days |
| Rabies | 2-8 weeks (can be 1 year+) |
| Malaria (P. falciparum) | 9-14 days |
| Malaria (P. vivax) | 12-17 days (or longer - relapse) |
| Dengue | 3-14 days (usually 4-7) |
| COVID-19 | 2-14 days (mean 5-6 days) |
| Leprosy | 2-5 years (range 6 months-20 years) |
ORS (Oral Rehydration Solution)
WHO-ORS (Reduced osmolarity, 2002):
- NaCl: 2.6 g/L
- Sodium citrate: 2.9 g/L
- KCl: 1.5 g/L
- Glucose (anhydrous): 13.5 g/L
- Total osmolarity: 245 mOsm/L (reduced from old 311 mOsm/L)
- Na: 75 mEq/L; K: 20 mEq/L; Cl: 65 mEq/L; Citrate: 10 mEq/L; Glucose: 75 mmol/L
Home-made ORS: 1 litre water + 6 tsp sugar + ½ tsp salt
TB Protocols
- Mantoux test: 5 TU of PPD; read at 48-72 hours; ≥10 mm induration = positive (≥5 mm in HIV/immunocompromised)
- CBNAAT/GeneXpert: Rapid molecular test; detects MTB + rifampicin resistance in 2 hours; preferred initial test
- TrueNat: Indigenous rapid molecular test; equivalent to GeneXpert
- LPA (Line Probe Assay): Detects INH + RIF resistance; for MDR-TB diagnosis
- Sputum smear AFB: ZN staining; rapid but less sensitive (needs 10,000 bacilli/mL)
Leprosy Protocols
Classification:
- PB (Paucibacillary): 1-5 skin lesions; smear negative; tuberculoid/BT
- MB (Multibacillary): >5 skin lesions; smear positive; lepromatous/BL/LL
MDT Regimens (WHO):
- PB: Dapsone 100 mg daily (self-administered) + Rifampicin 600 mg monthly (supervised) - 6 months
- MB: Dapsone 100 mg daily + Clofazimine 50 mg daily (self-administered) + Rifampicin 600 mg + Clofazimine 300 mg monthly (supervised) - 12 months
Lepromin test (Mitsuda reaction): Read at 28 days; not diagnostic but indicates immune response
Important Vectors in India
| Disease | Vector |
|---|---|
| Malaria | Anopheles mosquito (A. culicifacies main) |
| Dengue, Chikungunya, Zika | Aedes aegypti (primary), A. albopictus |
| Filariasis (lymphatic) | Culex quinquefasciatus |
| Japanese Encephalitis | Culex tritaeniorhynchus (rural), C. vishnui complex |
| Kala-azar (Leishmaniasis) | Phlebotomus argentipes (sandfly) |
| Plague | Xenopsylla cheopis (rat flea) |
| Scrub typhus | Leptotrombidium mite (chigger) |
| Murine typhus | Xenopsylla cheopis (rat flea) |
| Epidemic typhus | Pediculus humanus corporis (body louse) |
| Relapsing fever | Borrelia - louse-borne (Pediculus) or tick-borne (Ornithodoros) |
| Lyme disease | Ixodes tick |
| RMSF | Dermacentor tick (Rickettsia rickettsii) |
| Kyasanur Forest Disease (KFD) | Haemaphysalis spinigera tick |
SECTION 10: EXTRA HIGH-YIELD TOPICS
Disaster Management & Triage
PICE cycle: Preparedness → Incident → Crisis → Emergency (or P-R-R-R: Preparedness, Response, Relief, Recovery)
START Triage (Simple Triage and Rapid Treatment):
- Black (Expectant): Deceased or non-survivable injuries
- Red (Immediate): Life-threatening, survivable with immediate treatment
- Yellow (Delayed): Serious but not immediately life-threatening
- Green (Minimal): "Walking wounded"; minor injuries
SALT Triage: Sort → Assess → Lifesaving interventions → Treatment/Transport
Occupational Diseases
| Occupation/Exposure | Disease |
|---|---|
| Silica dust (miners, quarry) | Silicosis (most common pneumoconiosis) |
| Coal dust (coal miners) | Coal worker's pneumoconiosis (CWP) |
| Asbestos (shipbuilding, insulation) | Asbestosis + mesothelioma + lung cancer |
| Cotton dust (textile) | Byssinosis ("Monday fever") |
| Bagasse (sugarcane fiber) | Bagassosis |
| Mushroom growing | Mushroom worker's lung |
| Bird feathers | Bird fancier's lung |
| Benzene | Aplastic anemia, leukemia |
| Vinyl chloride | Angiosarcoma of liver |
| Isocyanates (TDI) | Occupational asthma |
| Lead | Lead poisoning (Burton's line, anemia) |
| Mercury | Minamata disease |
| Cadmium | Itai-itai disease |
| Fluoride (endemic) | Fluorosis (dental + skeletal) |
| Noise (>85 dB, 8 hrs/day) | NIHL (Noise-induced hearing loss) |
Family Cycle (Family Life Cycle)
Stages by Duvall:
- Couple (married, no children)
- Childbearing (oldest child 0-30 months)
- Pre-school age family
- School-age family
- Family with teenagers
- Launching family (first to last child leaving)
- Middle-age family (empty nest)
- Aging family (retirement to death)
Bioterrorism Categories (CDC)
Category A (Highest priority - easily disseminated, high mortality):
- Anthrax (Bacillus anthracis)
- Smallpox (Variola virus)
- Plague (Yersinia pestis)
- Tularemia (Francisella tularensis)
- Botulism (Clostridium botulinum toxin)
- Viral hemorrhagic fevers (Ebola, Marburg)
Category B: Moderate dissemination (Brucellosis, Typhus fever, Ricin toxin, Q fever)
Category C: Emerging pathogens (Nipah, Hantavirus)
Mental Health & Suicide Indicators
- NMHP (National Mental Health Programme): Launched 1982
- DMHP (District Mental Health Programme): Started 1996, Bellary
- Mental Healthcare Act 2017: Right to mental healthcare; advance directive; right to confidentiality
- Suicide rate (India): ~12/100,000 (NCRB data)
- Most common method in India: Hanging; then self-poisoning (pesticides)
- Durkheim's classification: Egoistic, Altruistic, Anomic, Fatalistic
- Prevention: ASSIST tool (Alcohol, Smoking and Substance Involvement Screening Test); SAFE-T protocol
WHO, UNICEF, SDGs
WHO:
- Headquarters: Geneva, Switzerland
- Founded: April 7, 1948 (World Health Day)
- "Health is a state of complete physical, mental and social well-being, not merely absence of disease or infirmity" - WHO 1948
UNICEF:
- United Nations Children's Emergency Fund; NY headquarters
- Works on child survival, development, protection
SDGs (Sustainable Development Goals):
- 17 goals adopted 2015, target year 2030 (replaced MDGs)
- SDG 3: "Good Health and Well-being" - most directly health-related
- 3.1: Reduce MMR to <70/100,000
- 3.2: End preventable deaths of U5 and neonates
- 3.3: End AIDS, TB, malaria, NTDs
- 3.4: Reduce NCDs by 1/3
- 3.8: Universal Health Coverage (UHC)
- SDG 1: No poverty; SDG 2: Zero hunger; SDG 6: Clean water
NHSRC, NIHFW, NCDC: National institutes under MoHFW India
QUICK REVISION: MOST TESTED ONE-LINERS
- Gold standard for studying rare diseases: Case-control study
- Gold standard for causation: RCT
- Measure in cohort study: Relative Risk (RR)
- Measure in case-control: Odds Ratio (OR)
- Sensitivity test: Rule OUT disease (SnNout)
- Specificity test: Rule IN disease (SpPin)
- P = I × D: Prevalence = Incidence × Duration
- Live vaccines: BCG, OPV, MMR, Varicella, Yellow fever
- Don't freeze: DPT, TT, Hepatitis B, Hib, IPV, PCV
- VVM: Inner square lighter than outer = usable; same/darker = discard
- ICDS launched: 1975, Oct 2
- Exclusive breastfeeding: 6 months
- Pearl index - best method: Vasectomy (0.1)
- NRR = 1: Replacement level fertility
- John Snow: Father of Epidemiology; Broad Street pump cholera 1854
- Bhore Committee: PHC concept introduced
- Kartar Singh Committee: MPW scheme, basis of sub-centre
- Srivastava Committee: Community Health Worker → basis of ASHA
- CHC serves: 120,000 population; 30 beds; 4 specialists
- Kala-azar vector: Phlebotomus argentipes (sandfly)
- Plague vector: Xenopsylla cheopis (rat flea)
- ORS osmolarity (reduced): 245 mOsm/L
- Leprosy elimination year in India: 2005 (<1/10,000 population)
- NTEP target: TB elimination by 2025
- NACP V target: 95-95-95 by 2025
- HPV 16+18: 70% cervical cancers
- HPV 6+11: Genital warts
- No-scalpel vasectomy in India: 1992
- Silicosis: Most common pneumoconiosis
- World Health Day: April 7 (WHO founding day 1948)
Source: Park's Textbook of Preventive and Social Medicine (23rd Ed.) - available in medical library
This covers every topic in your syllabus. A few notes for exam prep:
- Most heavily tested areas in NEET-PG/INI-CET/FMGE: Sensitivity/Specificity calculations, Study designs (can you compute RR/OR from a 2×2 table?), Vaccine types (live vs killed), National Immunization Schedule, Health indices (formulas + current India values), and Committee recommendations.
- Numerical questions typically come from: Pearl Index formula, Sensitivity/Specificity/PPV/NPV from a 2×2 table, NRR/TFR calculations, and Normal distribution SD ranges.
- Recent updates (2023-2026): HPV vaccine in UIP, NACP V goals, Nikshay Poshan Yojana, PM POSHAN (renamed MDM), IMI 3.0, Ayushman Bharat PMJAY expansion.
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