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PSM Paper I - AKU Bihar | Complete Descriptive Answers

Reference: Park's Textbook of Preventive and Social Medicine (K. Park)

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SECTION I: MAN AND MEDICINE - TOWARDS HEALTH FOR ALL

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Human Development Index (HDI)

1. Long and healthy life - measured by life expectancy at birth
2. Knowledge - measured by mean years of schooling (adults) and expected years of schooling (children)
3. Decent standard of living - measured by Gross National Income (GNI) per capita (PPP USD)

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Millennium Development Goals (MDGs)

1. Eradicate extreme poverty and hunger
2. Achieve universal primary education
3. Promote gender equality and empower women
4. Reduce child mortality (by 2/3)
5. Improve maternal health (reduce MMR by 3/4)
6. Combat HIV/AIDS, malaria and other diseases
7. Ensure environmental sustainability
8. Develop a global partnership for development

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Difference Between Monitoring and Evaluation

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DALY - Disability Adjusted Life Year

• YLL = Number of deaths x Standard life expectancy at age of death
• YLD = Number of incident cases x Duration of disease x Disability weight (0 to 1)

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Multifactorial Causation of Disease (Web of Causation)

• Host factors (age, sex, genetics, immunity, nutritional status, behaviour)
• Agent factors (biological, chemical, physical, nutritional)
• Environmental factors (physical, biological, social, economic)

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Epidemiological Triad

1. Host - the organism harboring the disease (susceptible human) - age, sex, race, immunity, nutrition, habits
2. Agent - the causative factor (biological, chemical, physical, nutritional)
3. Environment - external factors that influence host-agent interaction - physical (climate, geography), biological (insects, reservoir), socioeconomic (poverty, education)

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PQLI - Physical Quality of Life Index

1. Infant mortality rate (per 1000 live births)
2. Life expectancy at age 1
3. Basic literacy rate (%)

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Levels of Prevention

• Health promotion: education, nutrition, housing, recreation, genetic counseling
• Specific protection: immunization, chemoprophylaxis, safety measures, control of environmental hazards

• Early diagnosis: screening tests, case finding surveys
• Prompt treatment: minimize disability, prevent spread to others

• Disability limitation: prevent further complications
• Rehabilitation: restoration to optimal functioning - medical, social, vocational, psychological

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Iceberg Phenomenon of Disease

• Floating tip = Clinically apparent/diagnosed cases seen by physicians
• Submerged part = Hidden mass of disease including:
  • Sub-clinical cases (pre-symptomatic)
  • Undiagnosed cases
  • Carriers (healthy, convalescent, temporary, chronic)
  • Cases not presenting for treatment

1. These undiagnosed cases serve as reservoirs of infection and spread disease in community
2. They represent a huge disease burden not captured by hospital statistics
3. They help understand the true prevalence of disease
4. Detection requires active screening, not passive surveillance
5. Diseases like diabetes, hypertension, TB, HIV show prominent iceberg phenomena

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Social Factors in Health and Disease

1. Poverty: Most important cause of ill health. Leads to malnutrition, poor housing, unhygienic conditions, inability to access healthcare.
2. Education: Low literacy is associated with poor health awareness, less use of health services, higher fertility, poor child nutrition.
3. Occupation: Certain occupations carry specific health hazards (silicosis in miners, farmer's lung in farmers).
4. Housing: Overcrowding leads to spread of respiratory diseases (TB, meningococcal disease). Poor sanitation leads to diarrhoeal diseases.
5. Religion and customs: Dietary taboos may cause nutritional deficiencies. Religious practices may expose to infections.
6. Social class: Higher social class = better health outcomes. Kuppuswamy and Prasad scales classify socioeconomic status.
7. Migration and urbanization: Associated with breakdown of family support, stress, unhealthy lifestyles.
8. Social support systems: Families, communities provide health support and act as social safety nets.

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Dimensions of Health

1. Physical dimension: Good body functioning, absence of disease, adequate energy for daily tasks
2. Mental/Psychological dimension: Ability to think clearly, express emotions, face challenges, problem-solve
3. Social dimension: Ability to interact with others, form relationships, contribute to community
4. Spiritual dimension: Sense of purpose and meaning in life, moral values
5. Emotional dimension: Ability to recognize, accept and express emotions appropriately
6. Vocational dimension: Finding satisfaction in work and life roles

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Primordial Prevention

• Coined by: Strasser (1978), adopted by WHO
• Definition: Prevention of the emergence or development of risk factors in populations/countries where they have not yet appeared
• Examples: National food and nutrition policy, anti-smoking legislation for children, promoting physical activity from childhood
• Diseases targeted: CHD, hypertension, obesity, diabetes - "lifestyle diseases"
• Main tool: Health education and social/environmental policy
• Difference from primary prevention: Primordial acts before risk factors develop; primary prevention acts after risk factors exist but before disease develops

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Human Poverty Index (HPI)

1. Probability of not surviving to age 40 (expressed as %)
2. Adult illiteracy rate
3. Deprivation in economic provisioning = % without access to safe water + % without access to health services + % children under 5 who are underweight (average of three)

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Concept of Wellbeing/Wellness

• Subjective feeling of happiness and life satisfaction
• Ability to pursue goals and function effectively
• Freedom from distress and negative emotions
• Social connections and purpose

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Health Indicators

1. Mortality indicators: Crude Death Rate, Age-specific death rates, Infant Mortality Rate (IMR), Under-5 Mortality Rate, Maternal Mortality Rate, Life expectancy at birth
2. Morbidity indicators: Incidence rate, Prevalence rate, attack rate, notification rates
3. Disability indicators: Days of restricted activity, bed disability days
4. Nutritional status indicators: Anthropometric measures (weight, height, MUAC)
5. Healthcare delivery indicators: Doctor-population ratio, bed-population ratio, immunization coverage
6. Utilization indicators: OPD attendance rate, hospital admission rates
7. Socioeconomic indicators: Per capita GNP, literacy rate, housing conditions
8. Composite indices: IMR (single best indicator of overall community health), HDI, PQLI, DALY

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Measures of Morbidity

• Formula: (New cases in period / Population at risk) x 1000
• Reflects risk of getting disease; useful for acute diseases

• Point prevalence: Cases at a specific point in time / Total population at that time x 1000
• Period prevalence: All cases during a period / Average population x 1000
• Reflects disease burden; useful for chronic diseases

• Attack Rate: Cases / Population exposed x 100 (used in epidemics)
• Secondary Attack Rate (SAR): See epidemiology section
• Case Fatality Rate: Deaths from disease / Cases of disease x 100
• Bed Occupancy Rate, Hospital episode statistics

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Rehabilitation

1. Medical rehabilitation: Restoration of function - physiotherapy, occupational therapy, prosthetics
2. Vocational rehabilitation: Return to gainful employment - retraining, sheltered workshops
3. Social rehabilitation: Reintegration into family and society - social skills, independence
4. Psychological rehabilitation: Counseling, mental health support

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Health Education is NOT Health Propaganda - Justify

1. Provides accurate, scientific information
2. Develops critical thinking and informed decision-making
3. Empowers individuals to take responsibility for their own health
4. Respects autonomy and freedom of choice
5. Uses participatory methods
6. Leads to lasting behaviour change based on understanding

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SECTION II: CONCEPT OF HEALTH AND DISEASE

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Psychosocial Factors in Health and Disease

• Personality type: Type A personality (competitive, time-urgent, hostile) - associated with CHD
• Stress and coping mechanisms
• Depression, anxiety disorders
• Self-efficacy and health behaviour

• Social support networks
• Socioeconomic status
• Social isolation
• Life events (bereavement, divorce, job loss)

• Chronic stress - immunosuppression, hypertension, peptic ulcer
• Depression - poorer outcomes in all diseases
• Social isolation - increased mortality
• Low SES - poor nutrition, housing, healthcare access

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Socio-cultural Factors in Health and Disease

1. Culture and beliefs: Traditional medicine use, delay in seeking modern healthcare, taboos on certain foods
2. Religion: Female genital mutilation in some cultures; cow worship preventing beef consumption
3. Family structure: Joint family = social support; nuclear family = isolation
4. Social norms: Stigma around mental illness, TB, HIV prevents help-seeking
5. Gender roles: Women's low status, limited decision-making power affects maternal and child health
6. Language barriers: Non-communication with healthcare providers
7. Concept of disease causation: Supernatural beliefs delay rational treatment

• Protein-energy malnutrition linked to cultural food taboos in children
• Low female literacy linked to high MMR and IMR
• Stigma around leprosy causes delayed diagnosis

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SECTION III: PRINCIPLES OF EPIDEMIOLOGY AND METHODS

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Epidemiology - Definition

• Distribution: Who (person), where (place), when (time) - descriptive epidemiology
• Determinants: Why and how - risk factors, causes - analytical epidemiology
• Health-related states: Not just disease but also injuries, disabilities, health-promoting behaviours
• Specified populations: Community or defined groups

1. To describe the natural history of disease
2. To determine the extent of disease burden (magnitude)
3. To identify risk factors and causes of disease
4. To describe the health of communities
5. For evaluation of health services
6. For prediction of future disease trends
7. As a research tool in clinical medicine

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Types of Epidemiological Studies

1. Descriptive Studies: Describe distribution by person, place, time. Generate hypotheses. No comparison group. Examples: case reports, case series, ecological studies, cross-sectional surveys.
2. Analytical Studies:
   • Cross-sectional (Prevalence) study: Exposure and disease measured simultaneously. Gives prevalence. Good for chronic diseases. Cannot establish temporality.
   • Case-control study: Starts from disease (cases vs controls), looks back at exposure. Retrospective. Good for rare diseases and multiple exposures.
   • Cohort study: Starts from exposure (exposed vs unexposed), follows forward for disease. Prospective. Best for establishing causation. Gives incidence and relative risk.

1. Randomized Controlled Trial (RCT): Gold standard. Random allocation to intervention vs control. Blinding reduces bias. Evaluates efficacy of treatment/preventive measures.
2. Community Trial: Intervention applied to communities (not individuals).
3. Field Trial: Preventive agent tested in disease-free population.

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Case-Control Study

• Retrospective (looks backward)
• Starts with disease status
• Suitable for rare diseases and diseases with long latency
• Relatively quick and inexpensive
• Multiple exposures can be studied simultaneously
• Cannot calculate incidence rate directly

1. Formulate hypothesis
2. Define the disease/condition
3. Select cases (incident cases preferred; must have clear diagnostic criteria)
4. Select appropriate controls (hospital-based or community-based)
5. Match cases and controls (age, sex, etc.)
6. Collect data on exposure (interview, records)
7. Analyze data (Odds Ratio as measure of association)
8. Interpret results

• OR = (a x d) / (b x c) from a 2x2 table
• OR > 1 suggests positive association
• OR = 1 suggests no association
• OR < 1 suggests negative/protective association

• Recall bias (cases remember exposure better than controls)
• Selection bias (improper selection of cases/controls)
• Observer bias (systematic error in data collection)
• Interviewer bias

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Cohort Study

• Prospective cohort: Exposure identified first, then followed forward in time for outcomes
• Retrospective (historical) cohort: Exposure identified from past records, outcomes already known
• Ambidirectional cohort: Both prospective and retrospective components

1. Select the study population (exposed and unexposed cohorts)
2. Ensure disease-free at start
3. Measure exposure (baseline data)
4. Follow up for disease outcome
5. Calculate incidence in both groups
6. Calculate Relative Risk

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Case-Control vs Cohort Study

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Randomized Controlled Trial (RCT)

1. Randomization: Participants randomly allocated to intervention or control group - ensures comparable groups
2. Control group: Receives placebo or standard treatment for comparison
3. Blinding:
   • Single blind: Subject does not know group assignment
   • Double blind: Neither subject nor investigator knows
   • Triple blind: Subject, investigator, and analyst are all blinded
4. Outcome measurement: Pre-defined primary and secondary outcomes
5. Analysis: Intention-to-treat principle

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Incidence vs Prevalence

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Isolation vs Quarantine

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Secondary Attack Rate (SAR)

1. Measure of communicability/transmissibility of a disease
2. Measure of effectiveness of infectious agent
3. Useful for measuring herd immunity
4. Used to evaluate control measures
5. Helps predict epidemic potential

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Epidemic Investigation (Steps)

1. Confirm the diagnosis: Verify cases are real, establish case definition
2. Confirm the existence of epidemic: Compare current rates with baseline (expected) rates
3. Define the population at risk: Who is affected?
4. Rapid search for cases: Active case finding, describe cases by person, place, time
5. Construct epidemic curve: Plot number of cases vs time of onset - helps determine type and source
6. Develop hypotheses: About source, mode of transmission, population at risk
7. Test hypotheses: Analytical studies (case-control or cohort)
8. Institute control measures: Should not wait for investigation to be complete
9. Prepare a report: For record and future reference

• Common source (point source): All cases exposed at same time/place - sharp rise and fall; incubation period = interval from exposure to median case
• Propagated (person-to-person): Gradual rise, prolonged course, successive waves; interval = incubation period
• Mixed: Start as common source, then person-to-person

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Relative Risk (RR)

• RR = 1: No association
• RR > 1: Positive association (exposure increases risk)
• RR < 1: Negative association (protective effect)

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Sources of Bias

1. Selection bias: Systematic error in selection of study subjects. Example: Berkson's bias (hospital-based controls), non-response bias, prevalence-incidence bias (Neyman's bias)
2. Information (measurement) bias:
   • Recall bias: Cases remember exposure better than controls (common in case-control)
   • Observer/Interviewer bias: Observer knows hypothesis; records exposure differently
   • Reporting bias: Under/over-reporting of socially sensitive information
3. Confounding bias: Third variable associated with both exposure and outcome distorts the observed relationship. Example: Alcohol confounding the relationship between coffee and CHD.

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ICD Classification

• Uniform classification of diseases for statistical purposes
• Enables comparison of morbidity/mortality data across countries and time
• Basis for health information systems

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Infection vs Infestation

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SECTION IV: SCREENING FOR DISEASE

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Criteria for Screening (Wilson and Jungner, 1968)

1. Should be an important public health problem (high prevalence/severity)
2. Natural history should be well understood
3. There should be a recognizable latent or early symptomatic stage
4. Effective treatment must be available for the disease
5. Treatment applied at an early stage should be more beneficial than at later stages

1. Should be simple, safe, and acceptable to population
2. Sensitivity and specificity should be high
3. Should be inexpensive and easy to administer
4. Should be repeatable and reliable
5. Cut-off values should be agreed upon

1. Should be continuous (not a one-time event)
2. Benefits should outweigh physical and psychological harms
3. Cost should be balanced against expenditure on medical care as a whole

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Sensitivity and Specificity

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Validity of Screening Test

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ORS as Appropriate Technology - Justify

1. Affordable: Cost is negligible; can be made from household sugar and salt
2. Available: Ingredients universally available; ORS packets distributed through government programs
3. Simple to use: Mothers can prepare and administer at home; no medical training required
4. Effective: Proven to reduce mortality from diarrhoeal dehydration by 90%+
5. Acceptable: Oral administration, no needles
6. Applicable: Can be used in all settings - home, village, health center
7. Scalable: Can be deployed across populations without infrastructure

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SECTION V: EPIDEMIOLOGY OF INFECTIOUS DISEASES

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Intradermal Rabies Vaccination / Post-Exposure Prophylaxis (PEP)

1. Wound washing: Thorough washing with soap and water for 15 min (most important step)
2. Immunoglobulin (RIG): Rabies immunoglobulin infiltrated around wound
   • HRIG: 20 IU/kg body weight
   • ERIG: 40 IU/kg body weight
3. Vaccine: ARV (anti-rabies vaccine) as per schedule

• Category I: Touching/feeding animals, licks on intact skin - No PEP
• Category II: Nibbling of uncovered skin, minor scratches - Wound care + vaccine only
• Category III: Single/multiple transdermal bites, licks on broken skin, contamination of mucous membrane - Wound care + RIG + vaccine

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Cholera

• Source: Cases and carriers; contaminated water/food
• Transmission: Feco-oral, mainly waterborne; also foodborne
• Incubation period: Few hours to 5 days (usually 1-2 days)
• Infectious period: During illness (5-7 days); carriers may shed for months

1. Safe water supply and sanitation
2. Case isolation and treatment (ORS, IV fluids for severe; doxycycline)
3. Contact tracing and surveillance
4. Vaccination (Shanchol - oral killed vaccine; 2 doses; WHO pre-qualified)
5. Health education - personal hygiene, boiling water

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Dengue Fever - Epidemiology and Control

• Undifferentiated fever
• Dengue fever (DF): High fever, severe headache, retroorbital pain, myalgia, arthralgia ("breakbone fever"), rash
• Dengue Hemorrhagic Fever (DHF): Thrombocytopenia, hemorrhagic manifestations, plasma leakage
• Dengue Shock Syndrome (DSS): Rapid pulse, narrow pulse pressure, hypotension

1. Vector control (most important - no vaccine/specific antiviral):
   • Source reduction: Eliminate breeding sites (empty containers, cover water storage)
   • Larval control: Temephos (abate) in water containers; Bacillus thuringiensis israelensis (Bti)
   • Adult mosquito control: Space spraying (malathion, pyrethroid)
   • Biological control: Gambusia fish, copepods
2. Personal protection: Repellents, mosquito nets, full-sleeve clothing, screens on windows
3. Community education: "Search and destroy" campaigns
4. Surveillance: Integrated disease surveillance
5. Case management: Supportive (IV fluids, monitor platelets); no aspirin/NSAIDs

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Measles Vaccine

• 1st dose: 9 completed months (or at first contact if not given)
• 2nd dose: 15 months (MR vaccine)
• Also given at 5 years as MMR booster

• Measles depletes Vitamin A stores causing immunosuppression
• Vitamin A reduces measles mortality by 50% and prevents complications
• WHO recommends Vitamin A supplementation for all children with measles in developing countries
• 2 doses: 200,000 IU on two consecutive days (50,000 IU for infants under 6 months; 100,000 IU for infants 6-11 months)

• Live attenuated vaccines produce active infection that closely mimics natural infection
• Stimulate both humoral (antibody) and cellular (T-cell) immunity
• Longer duration of protection, often lifelong
• Fewer doses needed
• Spread through community (herd immunity bonus with oral polio vaccine)
• Killed vaccines primarily stimulate humoral immunity; require booster doses; adjuvants needed
• However, live vaccines have risks in immunocompromised persons; killed vaccines are safer

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Foodborne Diseases and Intoxications

1. Food Infections: Ingestion of living organisms that multiply in gut
   • Salmonella (poultry, eggs, meat) - IP 12-36 hours
   • Campylobacter (poultry, unpasteurized milk)
   • Listeria (ready-to-eat meats, soft cheese)
   • Vibrio cholerae
2. Food Intoxications (Toxinoses): Preformed toxin in food; no need for live organisms
   • Staphylococcal: IP 1-6 hours; vomiting, cramps; toxin in cream-based foods; heat-stable toxin
   • Botulism: IP 12-36 hours; descending flaccid paralysis; home-canned foods; C. botulinum toxin
   • Bacillus cereus: 2 types - emetic (1-6 hr, rice) and diarrheal (8-16 hr)
   • Clostridium perfringens: IP 8-12 hours; meat dishes; diarrheal illness
3. Chemical food poisoning: Pesticide residues, heavy metals, aflatoxins

1. Confirm diagnosis and existence of outbreak
2. Identify food vehicle (food-specific attack rates)
3. Collect food/stool/vomit samples
4. Identify pathogen and control source

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NTEP (National Tuberculosis Elimination Programme)

• Intensive phase: 2 months HRZE (Isoniazid, Rifampicin, Pyrazinamide, Ethambutol)
• Continuation phase: 4 months HR

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Prevention of Parent-to-Child Transmission (PPTCT) of HIV

1. Option B+ (India's policy): All HIV+ pregnant women started on lifelong ART (TDF + 3TC + EFV) regardless of CD4 count, from diagnosis
2. For baby: Nevirapine (NVP) syrup for 6 weeks after birth
3. Infant feeding counseling: Exclusive breastfeeding for 6 months if safe replacement unavailable; otherwise infant formula
4. Cotrimoxazole prophylaxis: For exposed infant from 6 weeks
5. Early Infant Diagnosis: PCR test at 6 weeks to diagnose HIV in infant
6. Voluntary counseling and testing (VCTC): All pregnant women offered HIV test at antenatal care

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Yellow Fever

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DEC in Filariasis

• Mass Drug Administration (MDA): Annual MDA programme using DEC + Albendazole to entire at-risk population (except children <2 years, pregnant women, severely ill)
• In Aedes islands (endemic areas): Triple drug therapy - DEC + Albendazole + Ivermectin (IDA)

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SECTION VI: NUTRITION AND HEALTH

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Epidemic Dropsy

• Pitting edema of lower extremities (main feature - "dropsy")
• Erythema, vesiculation of skin
• Glaucoma (20%)
• Anemia
• Diarrhea, nausea
• Breathlessness (cardiac failure)
• Tender hepatomegaly

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Pasteurization of Milk

1. HTST (High Temperature Short Time / "Flash" pasteurization): 72°C for 15 seconds - most widely used
2. LTLT (Low Temperature Long Time / Holder method): 63°C for 30 minutes
3. Ultra High Temperature (UHT): 135°C for 1-2 seconds - long shelf life; no refrigeration needed
4. Sterilization: 100°C for 20-30 min - kills all organisms including spores

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Herd Immunity

1. Protects vulnerable individuals (immunocompromised, infants) who cannot be vaccinated
2. Basis for mass vaccination programs and UIP targets
3. Can lead to disease elimination when sustained

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Marasmus (Protein-Energy Malnutrition)

• Marasmus: Predominantly energy deficiency; early weaning; ages 6 months to 2 years
• Kwashiorkor: Predominantly protein deficiency; late weaning; 1-3 years
• Marasmic-Kwashiorkor: Mixed

• Severe wasting of muscle and fat (Weight for age < 60% of standard)
• "Wizened old man" appearance
• Gross emaciation, "skin and bones"
• No edema (differentiates from kwashiorkor)
• Preserved hair color and skin
• Sunken eyes, loose skin, prominent ribs
• Apathetic but alert
• Severe stunting of growth

• Edema (pitting), especially feet and legs
• Growth failure
• Psychomotor changes, apathy, irritability
• "Flag sign" (alternating bands of depigmented/normal hair)
• "Flaky paint" dermatosis
• Fatty liver

• F-75 then F-100 therapeutic milk feeds (WHO protocol)
• RUTF (Ready-to-Use Therapeutic Food) - Plumpy'Nut
• Micronutrient supplementation
• Treat infections

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Lathyrism and Neurolathyrism

• Sudden onset spastic paraplegia
• Scissor gait ("cross-legged" walk)
• "Tin tap" sound while walking (due to spasticity)
• Upper motor neuron signs: hyperreflexia, clonus, extensor plantar
• Sensory function preserved
• No cognitive impairment

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Vitamin A Deficiency and Xerophthalmia

• XN: Night blindness (Nyctalopia) - earliest symptom
• X1A: Conjunctival xerosis (dry, rough conjunctiva)
• X1B: Bitot's spots (foamy, triangular white plaques on conjunctiva)
• X2: Corneal xerosis
• X3A: Corneal ulceration < 1/3 cornea
• X3B: Keratomalacia (corneal softening - causes blindness)
• XS: Corneal scar
• XF: Xerophthalmic fundus (retinal changes)

• 6-11 months: 1 lakh IU oral Vitamin A (with measles vaccine at 9 months)
• 12-23 months: 2 lakh IU every 6 months
• 24-59 months: 2 lakh IU every 6 months

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Nutritional Anaemia

1. Iron deficiency (most common)
2. Folate deficiency
3. Vitamin B12 deficiency
4. Vitamin A deficiency (secondary)

• Children 6m-5yr: Hb < 11 g/dL
• Children 5-11yr: Hb < 11.5 g/dL
• Children 12-14yr: Hb < 12 g/dL
• Non-pregnant women: Hb < 12 g/dL
• Pregnant women: Hb < 11 g/dL
• Men: Hb < 13 g/dL

1. Iron-folic acid supplementation (IFA):
   • Children 6-59 months: 25 mg elemental iron + 100 mcg folic acid 3x/week
   • Children 5-9 yr: 45 mg Fe + 400 mcg folic acid weekly
   • Adolescents 10-19 yr: 60 mg Fe + 500 mcg folic acid weekly
   • Pregnant women: 180 mg elemental iron + 5 mg folic acid (daily for 180 days)
   • Lactating women: 180 mg iron + 5 mg folic acid (daily x 180 days)
2. Deworming: Albendazole every 6 months (reduces hookworm-related blood loss)
3. Food fortification: Double-fortified salt (Fe + iodine), fortified rice, wheat flour
4. WASH interventions: Safe water, sanitation reduces helminthic infection
5. Dietary diversification: Iron-rich foods (meat, green leafy vegetables), ascorbic acid to enhance absorption; avoid tea/coffee with meals

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Food Fortification

• Mass/Universal fortification: Staple foods fortified without individual testing (salt, wheat flour, rice, edible oil)
• Targeted fortification: For specific vulnerable groups (complementary foods for young children)
• Market-driven/voluntary fortification: Food industry adds nutrients based on market demand

• Iodized salt (universal salt iodization - USI)
• Double-fortified salt (iodine + iron)
• Fortified rice (Fe, Folic acid, B12) - distributed through PDS
• Fortified wheat flour/maida
• Fortified edible oil (Vitamin A and D)

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"Breast Milk is Ideal for Infants till 6 Months" - Justify

1. Complete nutrition: Contains all nutrients in right proportions (fat, protein, carbohydrates, vitamins, minerals) for optimal infant growth
2. Immunological protection:
   • Secretory IgA - protects gut mucosa from pathogens
   • Lactoferrin - antimicrobial
   • Lysozyme, macrophages, lymphocytes
   • Colostrum (first milk) - rich in antibodies and immune cells
3. Prevents infections: Reduces risk of diarrhoea by 6-10x, acute respiratory infections by 2-3x, meningitis
4. Prevents allergies: Reduces risk of eczema, asthma, food allergies
5. Bioavailability: Nutrients (especially iron, zinc, calcium) are more bioavailable from breast milk than formula
6. Bonding and brain development: Promotes mother-child bonding; DHA and ARA in breast milk support brain development
7. Benefits for mother: Reduces risk of breast and ovarian cancer, natural contraception (LAM), helps uterine involution
8. Economic: Free, always available at right temperature
9. WHO recommends: Exclusive breastfeeding for 6 months, then continue with complementary feeding till 2 years

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Global Hunger Index (GHI)

1. Undernourishment: % of population with insufficient caloric intake
2. Child wasting: % of children <5 with low weight-for-height
3. Child stunting: % of children <5 with low height-for-age
4. Child mortality: Under-5 mortality rate

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SECTION VII: MEDICINE AND SOCIAL SCIENCES

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Doctor-Patient Relationship

1. Activity-Passivity model: Doctor active, patient passive; used in emergency/coma. Like parent-infant.
2. Guidance-Cooperation model: Doctor guides, patient cooperates; used in acute illness. Like parent-child.
3. Mutual Participation model: Both contribute equally; used in chronic diseases. Like adult-adult.
4. Consumerism model: Patient as customer with right to choose.

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Interviewing Techniques

1. Structured interview: Pre-set questionnaire with fixed responses; standardized; used in surveys
2. Semi-structured interview: Core questions but allows exploration of responses
3. Unstructured (open-ended) interview: Free-flowing; in-depth; qualitative research

• Open-ended questions first, then closed
• Silence as a tool
• Reflection: repeating patient's words
• Clarification and summarizing
• Empathic statements
• Non-verbal communication (eye contact, posture)
• Active listening
• Avoid leading questions, medical jargon

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Types of Family

1. Nuclear family: Husband, wife, and unmarried children. Most common in urban India.
2. Joint family: Multiple generations or related families living together and sharing resources. Traditional Indian family.
3. Extended family: Nuclear family + other relatives (grandparents, aunts, uncles)
4. Single-parent family: One parent (due to death, divorce, separation)
5. Reconstituted (Blended) family: Remarriage - step-children
6. Matriarchal family: Female as head; common in Kerala (Nair community)
7. Patriarchal family: Male as head - most common

• Family is the basic unit of health care delivery
• Primary locus of health behaviour formation
• Social support system for illness management
• Genetic pool
• Family dysfunction associated with mental illness, substance abuse, child abuse

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Emotions in Health and Disease

• Peptic ulcer (stress, hostility)
• Hypertension (anxiety, repressed anger)
• Bronchial asthma (emotional triggers)
• Irritable bowel syndrome
• Eczema, psoriasis
• Migraine
• Diabetes (stress worsens control)

• Denial, anger, bargaining, depression, acceptance (Kubler-Ross stages)
• Anxiety about diagnosis
• Fear of death, disability, disfigurement

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Overcrowding

1. Respiratory diseases: TB, influenza, meningococcal meningitis, pertussis, streptococcal pharyngitis
2. Skin and eye infections: Trachoma, scabies, conjunctivitis
3. Gastrointestinal: Typhoid, dysentery (crowded conditions promote poor sanitation)
4. Mental health: Increased stress, domestic violence, poor sleep
5. Child development: Poor academic performance, reduced play space
6. Social problems: Incest, promiscuity

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SECTION VIII: ENVIRONMENT AND HEALTH

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Air Pollution - Indicators and Effects

• Primary: Directly emitted (SO₂, NO₂, CO, particulates, hydrocarbons)
• Secondary: Formed by chemical reactions in atmosphere (ozone, PAN, acid rain)

1. SPM (Suspended Particulate Matter): Dust, soot; PM₁₀ and PM₂.₅ most harmful
2. SO₂: Combustion of fossil fuels; acid rain; irritates respiratory mucosa
3. NO₂: Motor vehicles; brownish haze; acid rain
4. CO: Incomplete combustion; binds hemoglobin (COHb); hypoxia
5. Lead: Petrol additives (now reduced); neurotoxic
6. Ozone (O₃): Photochemical smog; respiratory irritant; also protective in stratosphere

• Respiratory: Increased COPD, asthma, bronchitis, lung cancer (PM₂.₅, SO₂)
• Cardiovascular: Ischemic heart disease, stroke (PM₂.₅)
• CO poisoning: Headache, dizziness, death at high concentrations
• Lead: Neurodevelopmental effects in children
• Indoor air pollution: Biomass fuel combustion (cooking) - major cause of respiratory disease in India; 4% of global DALYs

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Sand Filtration of Water

• Sand grain size: 0.2-0.4 mm; depth 90-120 cm; rate: 0.1-0.4 m/hr
• Vital layer (Schmutzdecke): Biological layer on top of sand - key to filtration; removes 98-99% bacteria
• Mechanism: Biological action (vital layer) + mechanical straining + adsorption
• Cleaning: Scraping top 2 cm sand layer (reverse flow washing impractical)
• Turbidity of raw water must be <10 NTU; preceded by plain sedimentation
• Efficiency: 98-99% bacterial removal; can handle low turbidity water; no chemicals needed

• Sand grain size: 0.4-0.7 mm; depth 60-75 cm; rate: 5 m/hr (50x faster)
• No vital layer; mechanism: mechanical filtration + coagulation (preceded by coagulation/flocculation with alum)
• Cleaned by backwashing (upward flow of water through sand)
• Can handle high turbidity water
• Requires coagulation + sedimentation before filtering
• Must be followed by chlorination (unlike slow sand filter - less effective bactericidal)

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Chlorination of Water

• Free available chlorine (FAC) = Chlorine + Hypochlorous acid (HOCl) + Hypochlorite ion (OCl⁻)
• HOCl is the most effective form; present at lower pH
• Residual chlorine after 30 min contact time: 0.2 mg/L (free residual chlorine in drinking water)

• When chlorine is added to water, it first reacts with organic matter and ammonia, forming chloramines (combined chlorine) with poor disinfecting power
• As more chlorine is added, chloramines are destroyed
• The "breakpoint" = point at which all chloramines are destroyed; further addition produces free residual chlorine
• Beyond breakpoint, chlorine residual rises again - this is FREE residual chlorine, which has excellent bactericidal activity
• Breakpoint chlorination = adding enough chlorine to exceed the breakpoint so that free residual chlorine is available

• pH (lower pH = more HOCl = better disinfection)
• Temperature (higher = faster reaction)
• Contact time (at least 30 minutes)
• Turbidity (high turbidity = less effective)
• Organic matter content

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Ventilation

1. Natural ventilation: Wind and thermal (buoyancy) effects; windows, doors, skylights; no energy required
2. Artificial/Mechanical ventilation: Fans, air conditioning; provides controlled airflow
3. Plenum system: Fresh air pumped in at slight positive pressure
4. Vacuum system: Vitiated air extracted, negative pressure
5. Combined system: Both supply and extract

• Window space: At least 1/10 of floor space = adequate ventilation
• CO₂ concentration: Pettenkofer's standard: CO₂ should not exceed 0.1% (1000 ppm); indicator of vitiation
• Air change per hour: Number of times indoor air is replaced; minimum 2-4 air changes/hour for habitable rooms; 10-15 for hospitals
• Ventilation rate: Volume of fresh air per person per minute; minimum 30 cu ft/min/person

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Coliform Organisms as Indicators of Faecal Pollution - Justify

1. Present in large numbers in feces of warm-blooded animals
2. Survive in water for similar or longer duration than pathogens
3. Easy and economical to detect (MPN test, membrane filtration)
4. Non-pathogenic themselves (mostly) - safe to handle
5. Not normally present in unpolluted water

• MPN (Most Probable Number): MacConkey broth; 3-tube/5-tube test; < 2 coliforms/100 mL (WHO standard for drinking water)
• Membrane filtration: Filter 100 mL water; incubate on nutrient agar; count coliform colonies

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Mosquito Control Measures

1. Environmental (source) control:
   • Drainage of stagnant water (Culex breeding)
   • Intermittent irrigation in rice fields
   • Filling of low-lying areas
   • Covering water storage containers (Aedes control)
   • Removal of unwanted containers, tyres
   • This is the best long-term method
2. Biological control:
   • Larvivorous fish: Gambusia affinis, Guppy (Lebistes reticulatus) - released in ponds, wells
   • Bacillus thuringiensis israelensis (Bti) - biological larvicide
   • Copepod crustaceans (against Aedes)
3. Chemical control:
   • Larvicides: Temephos (abate), Malathion, Paris green (copper acetoarsenite) - for Anopheles larvae
   • Adulticides: DDT (residual spray), Malathion (space spray), Pyrethroids
   • Fumigants: used in aircraft, containers
4. Personal protection:
   • Repellents: DEET, Picaridin
   • Insecticide-Treated Nets (ITNs) / LLINs
   • Protective clothing
   • Wire mesh on windows
5. Biological agents: Sterile insect technique (SIT), Wolbachia-infected Aedes

• Destroys breeding habitats permanently
• No development of resistance (unlike insecticides)
• Safe for environment; no chemical residues
• Cost-effective long-term
• Sustainable; community participation possible
• Insecticides have drawbacks: resistance, toxicity, ecological damage

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SECTION IX: HOSPITAL WASTE MANAGEMENT

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Health Hazards of Biomedical Waste (BMW)

1. Infectious waste: Contaminated with blood, body fluids, pathogens; wound dressings, culture media
2. Pathological waste: Human tissues, organs, body parts
3. Sharps: Needles, scalpels, blades - puncture hazard + infection risk (HIV, HBV, HCV)
4. Pharmaceutical waste: Expired/unused drugs
5. Genotoxic waste: Cytotoxics, chemotherapy agents
6. Chemical waste: Laboratory reagents, disinfectants
7. Radioactive waste: Used isotopes from nuclear medicine

• Healthcare workers: Needlestick injuries (HIV, HBV, HCV)
• Waste handlers: Infections, injuries, toxic exposure
• Community: Illegal reuse of syringes/needles from unprocessed waste; environmental contamination of water/soil; rag pickers' exposure
• Children: Playing with discarded medical items

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Segregation of Biomedical Waste (Colour-Coded Bags)

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Incineration

1. Multiple chamber incinerator (most common for BMW)
2. Rotary kiln
3. Plasma pyrolysis

• Reduces waste volume by 90%
• Destroys pathogens completely
• Handles wide range of waste categories
• Products: ash, flue gas

• Produces air pollution (dioxins, furans, heavy metals from flue gas)
• High capital and operating cost
• Requires trained operators
• Not suitable for sharps alone, recyclable plastics, or radioactive waste

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SECTION X: OCCUPATIONAL HEALTH

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Pneumoconioses

• Cause: Inhalation of free crystalline silica (SiO₂) - mining (gold, coal), quarrying, sandblasting, stone cutting
• Pathology: Silicotic nodules in upper lobes; progressive massive fibrosis (PMF)
• Types: Acute (high exposure, <5 yr), Accelerated, Chronic (>10 yr)
• Features: Progressive exertional dyspnea, cough; "eggshell calcification" of hilar lymph nodes on X-ray
• Complications: TB (silicosis increases TB risk 3x - "silicotuberculosis"), cor pulmonale, lung cancer
• Prevention: Dust suppression (wet drilling, water sprays), PPE (respirators), pre-employment and periodic medicals, engineering controls

• Cause: Amphibole and serpentine asbestos fibers (shipbuilding, insulation, asbestos cement)
• Pathology: Diffuse interstitial fibrosis; asbestos bodies (ferruginous bodies); pleural plaques
• Features: Dyspnea, clubbing, bilateral basal crepitations, restrictive pattern on PFT
• Complications: Mesothelioma (hallmark cancer - pleural/peritoneal), lung cancer (synergistic with smoking), pleural effusion

• Cause: Coal dust (carbon particles)
• Pathology: Coal macules, nodules; PMF in advanced cases (Caplan's syndrome if associated with rheumatoid arthritis)
• Features: Simple CWP (mostly asymptomatic) to PMF (massive fibrosis, cor pulmonale)
• Pathological finding: Black pigment deposits (anthracotic pigment) in lymph nodes and lung

• Cause: Hypersensitivity reaction to thermophilic actinomycetes in moldy sugarcane bagasse (sugar industry waste)
• Type: Extrinsic allergic alveolitis (hypersensitivity pneumonitis) - Type III + IV hypersensitivity
• Features: Fever, chills, dyspnea 4-8 hours after exposure; recurs with re-exposure
• Prevention: Dry the bagasse properly; PPE; engineering controls

• Cause: Hypersensitivity to Micropolyspora faeni (thermophilic actinomycetes) in moldy hay
• Similar mechanism and features to bagassosis

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Silicosis

• "The dust that injures is the dust that you cannot see" (particle size 0.5-5 μm is most dangerous - respirable fraction)
• X-ray findings: multiple small rounded opacities in upper zones; large opacities in PMF; eggshell calcification of hilar nodes
• No curative treatment; only preventive and symptomatic management

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ESI Act (Employees' State Insurance Act)

1. Sickness benefit: 70% of average daily wages for 91 days/year
2. Extended sickness benefit: For certain long-term diseases (TB, malignancy, mental illness) - 80% wages for 2 years
3. Enhanced sickness benefit: 100% wages for family planning operations
4. Maternity benefit: 100% wages for 26 weeks
5. Disablement benefit:
   • Temporary: 90% wages till recovery
   • Permanent: % of wages based on degree of disablement
6. Dependents' benefit: 90% of wages to dependants in case of death due to occupational injury
7. Medical benefit: Full medical care for self and family (ESI hospitals, dispensaries)
8. Funeral expenses: Rs 15,000 lump sum

• Employer: 3.25% of wages
• Employee: 0.75% of wages
• Below Rs 137/day wages: exempt from employee contribution

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Ergotism

1. Gangrenous ergotism (Ignis Sacer / St. Anthony's Fire): Vasoconstriction leading to dry gangrene of extremities; burning pain; blackening and loss of limbs
2. Convulsive (Nervous) ergotism: Convulsions, hallucinations, mental disturbances

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PEP for HIV (Post-Exposure Prophylaxis)

• Percutaneous exposure with hollow needle from HIV+ patient - highest risk (0.3%)
• Mucous membrane/intact skin - lower risk (0.09%)
• Intact skin - no risk

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SAFE Strategy for Trachoma

• S = Surgery for trichiasis (inturned lashes that scratch cornea)
• A = Antibiotics (mass administration of Azithromycin 1g single dose, or tetracycline eye ointment) to eliminate infection
• F = Facial cleanliness (regular face washing - especially children) - reduces transmission
• E = Environmental improvement (clean water, sanitation, fly control) - reduces transmission

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SECTION XI: ELEMENTS OF BIOSTATISTICS

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Sampling

1. Simple Random Sampling (SRS): Each individual has equal chance of selection; using random number tables or lottery. Gold standard but impractical for large scattered populations.
2. Systematic Random Sampling: Select every k-th individual (k = N/n); first individual chosen randomly. Simple and practical.
3. Stratified Random Sampling: Divide population into strata (subgroups, e.g., age groups), then randomly sample from each stratum. Ensures representation of all subgroups.
4. Cluster (Area) Sampling: Divide into clusters (villages, wards); randomly select clusters; survey all individuals in selected clusters. Most practical for field surveys. EPI survey uses 30 cluster x 7 = 210 subjects.
5. Multistage Sampling: Combination of sampling methods at different stages (state -> district -> village -> household)

• Purposive/judgmental, Convenience, Snowball, Quota sampling

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Normal Distribution and Normal Curve

1. Symmetrical about the mean
2. Mean = Median = Mode (all coincide at center)
3. Total area under curve = 1 (100%)
4. Defined by two parameters: Mean (μ) and Standard Deviation (σ)
5. Extends from -∞ to +∞

• Mean ± 1 SD includes 68.27% of observations
• Mean ± 2 SD includes 95.45% of observations
• Mean ± 3 SD includes 99.73% of observations

• Setting reference ranges (normal values) for clinical tests
• Calculating confidence intervals
• Basis for many statistical tests (t-test, z-test)

• In skewed distribution, mean is pulled toward the long tail (extreme values)
• Median is the middle value and is not affected by outliers/extreme values
• Mean = Median = Mode only in normal distribution
• In positively skewed data: Mean > Median > Mode; in negatively skewed: Mode > Median > Mean
• Therefore, for income distribution (positively skewed), disease outbreak data with outliers, or any asymmetric data - median is a better representative measure of central tendency

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Measures of Central Tendency

• Sum of all values / Number of values
• Most commonly used; uses all data; affected by extreme values (outliers)
• Suitable for normally distributed quantitative data

• Middle value when data arranged in ascending order
• If even number of values: average of two middle values
• Not affected by outliers; suitable for skewed data
• Used when there are extreme values or non-normal distribution

• Most frequently occurring value in a dataset
• Can be used for qualitative (nominal) data
• A dataset may be unimodal, bimodal, or multimodal
• Least affected by extreme values; least useful statistically

• Normal distribution: Mean preferred
• Skewed distribution: Median preferred
• Nominal/Categorical data: Mode used

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Measures of Dispersion

• SD = √[Σ(X-X̄)²/n]
• Small SD = data clustered around mean; Large SD = data spread out
• Uses all values; most efficient statistic

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Standard Deviation

• 95% CI = Mean ± 1.96 SE
• 99% CI = Mean ± 2.58 SE
• p < 0.05 is considered statistically significant (probability that results are due to chance is < 5%)

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Census

• Conducted every 10 years
• Last census: 2011 (2021 census delayed due to COVID)
• Conducted by: Registrar General and Census Commissioner of India
• Decennial (every 10 years)

1. Basis for all planning and policy making
2. Denominators for health statistics (rates and ratios)
3. Assess growth and distribution of population
4. Resource allocation to states/regions
5. Electoral constituency delimitation

• De facto census: Count people where they are found on census night
• De jure census: Count people at their usual place of residence (India uses this)

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Sources of Health Information

1. Census: Population data, demographic characteristics
2. Vital Statistics Registration System: Births (Civil Registration System), Deaths, Marriages - under Civil Registration System (CRS); only 75-80% complete in India
3. Sample Registration System (SRS): Continuous demographic survey providing birth rates, death rates, IMR; most reliable source of vital statistics in India
4. National Family Health Survey (NFHS): Household survey; fertility, mortality, family planning, nutrition data
5. Disease Surveillance Systems: IDSP (Integrated Disease Surveillance Programme), NVBDCP data
6. Hospital Records / Medical Records: Morbidity data but biased toward treated cases
7. Notification of diseases: Weekly/monthly notification of notifiable diseases
8. Insurance data: ESI, LIC claim records
9. School health records: Child health data
10. Social Security Records: ESIC data
11. Special surveys: NFHS, DLHS, Annual Health Survey (AHS)

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Exam Tips:

• Topics appearing 4+ times: Iceberg phenomenon, SAR, Chlorination, Nutritional anaemia - write detailed answers
• "Justify" questions: Write one paragraph establishing why the statement is correct with 4-5 logical points
• Long questions (marked): Levels of prevention, Cohort study, Dengue, Epidemic investigation - write 4-6 pages with diagrams
• Most repeated single topics: Levels of prevention, Iceberg, Cohort study, Case-control study, SAR, Nutritional anaemia, Chlorination, Ventilation

1. Scroll up to the big answer block that starts with "# PSM Paper I - AKU Bihar | Complete Descriptive Answers"
2. Click just before the first # character at the very beginning
3. Scroll all the way down to the last line ("...Most repeated single topics...")
4. Hold Shift + Click at the very end of the last line — this selects all text in between
5. Press Ctrl + C (Windows) or Cmd + C (Mac) to copy
6. Open Microsoft Word → Ctrl + V to paste

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• Use Ctrl + A then set font to Calibri 11pt or Times New Roman 12pt
• The # headings won't auto-format — you can use Find & Replace or manually apply Heading styles
• Tables should paste correctly as plain text tables

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• Proper heading levels (H1, H2, H3)
• Formatted tables
• Bold key terms
• Page numbers and a title page
• Print-ready margins