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GROUP A – LAQ MODEL ANSWERS (15 Marks Each)

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Q3. Dog Bite by a Street Dog [SRIMS]

i. Immediate Action (2 marks)

1. Stay calm and move your friend away from the dog.
2. Assess the wound - identify the type, location, and severity of bite.
3. Do NOT panic-suture the wound immediately.
4. Begin local wound treatment at once (see Part iii below).
5. Note the time, circumstances, and the dog's behavior (provoked vs. unprovoked, whether the dog ran away or was captured).
6. Take the friend to the nearest health facility as soon as possible.

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ii. Wound Categorization - WHO Exposure Categories (3 marks)

• The bite was unprovoked
• The dog is a stray (unvaccinated, unknown vaccination status)
• The animal ran away and cannot be observed

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iii. Management to Prevent Rabies (10 marks)

A. Local Wound Treatment (Most Important - First Line)

1. Cleansing: Flush and wash all wound(s) with copious soap and water under running tap for at least 15 minutes. If soap is unavailable, flush with plenty of water alone as first aid. For puncture wounds, use a catheter to irrigate deeply.
2. Chemical treatment: Apply virucidal agents to inactivate residual virus:
   • Alcohol (40-70%)
   • Tincture of iodine, OR
   • 0.01% aqueous povidone-iodine
3. Suturing: Do NOT suture immediately - this can spread the virus deeper. If suturing is unavoidable, wait 24-48 hours and use minimum stitches under cover of locally infiltrated RIG.
4. Antibiotics: Give amoxicillin-clavulanate (or appropriate antibiotic) to prevent secondary infection.
5. Anti-tetanus: Give tetanus toxoid and anti-tetanic serum if not previously immunized.

B. Post-Exposure Prophylaxis (PEP) - Immunization

• Administered once only, as soon as possible after exposure (not beyond Day 7 after first vaccine dose).
• Human RIG (HRIG): 20 IU/kg body weight
• Equine RIG (ERIG): 40 IU/kg body weight (skin test before use)
• Infiltrate maximum possible volume into and around the wound site(s); remaining volume given IM at a distant site from vaccine.

• Essen Regimen (5-dose): 1 dose on Days 0, 3, 7, 14, and 28 (into deltoid; thigh for children <2 years). This is the standard schedule.
• Zagreb Regimen (4-dose): 2 doses on Day 0 (one in each deltoid), then 1 dose on Days 7 and 21.

• 2-site ID regimen (2+2+2+0+2): 0.1 ml ID at 2 sites on Days 0, 3, 7, and 28 - used where nationally endorsed.

C. Patient Counseling and Follow-Up

• Advise patient to complete the full vaccine schedule.
• Monitor the dog (if captured) for 10 days - if it remains healthy, PEP may be discontinued.
• Report the bite to local health authorities.

D. Public Health Measures

• Notify the Animal Bite Treatment Centre and local health authorities.
• Register the case for Integrated Bite Case Management under the National Rabies Control Programme.

Source: Park's Textbook of Preventive and Social Medicine, pp. 323-326

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Q4. Acute Watery Diarrhoea Outbreak in Under-5 Children [SCCGMCH]

Part 1: Steps for Investigating the Outbreak (5 marks)

• Conduct a house-to-house medical survey to find unreported cases.
• Use an epidemiological case sheet to record: name, age, sex, time of onset, symptoms, food/water intake, common exposures, contact history.
• Case definition: Child under 5 with acute watery diarrhoea (≥3 loose stools in 24 hours) ± vomiting, with onset within the past 7 days.

• Time: Construct an epidemic curve (date/time of onset vs. number of cases). A sharp peak suggests a point-source (e.g., contaminated water supply).
• Place: Draw a spot map showing case locations relative to water sources, food stalls, etc.
• Person: Calculate attack rates by age group, sex, household, water source used.

• Treat cases (oral/IV rehydration)
• Chlorinate water supply or provide safe water
• Promote hand hygiene and proper sanitation
• Isolate/treat cases

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Part 2: IMNCI Classification of Dehydration for the Five Children (2 marks)

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Part 3: Management and Fluid Resuscitation - Plan C (5 marks)

• Reassess every 1-2 hours: If dehydration not improving, increase IV drip rate.
• Once the child can drink, start ORS (5 ml/kg/hour) alongside IV fluids.
• When child is no longer severely dehydrated, switch to Plan B or Plan A.

• Continue breastfeeding if the infant is breastfed.
• Give Zinc supplementation: 10 mg/day for infants <6 months; 20 mg/day for older children, for 14 days.
• If cholera is suspected in a child ≥2 years: give appropriate antibiotic (azithromycin).
• Monitor: pulse rate, respiratory rate, urine output, skin turgor, mental status.
• Referral: If IV access not possible, refer URGENTLY to hospital with mother giving frequent sips of ORS on the way.

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Part 4: Preventive and Control Measures (3 marks)

1. Safe Water Supply: Chlorinate the village water source (0.5 ppm residual chlorine); provide ORS/boiled water. Collect water samples for bacteriological testing.
2. Food Safety: Identify any common food vehicle; stop sales from implicated sources; educate on food hygiene.
3. Hand Hygiene: Actively promote hand washing with soap after defecation and before food preparation; set up hand-washing stations.
4. Environmental Sanitation: Proper disposal of faeces; chlorinate latrines; remove garbage; prevent open defecation.
5. Case Management: Treat all cases with ORS, zinc; severe cases referred for IV fluids.
6. Health Education: Mobilize community via ASHA workers, AWWs; advise on signs of dehydration.
7. Surveillance: Maintain daily line list; report under IDSP; monitor for new cases for at least 2 incubation periods after the last case.

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Q5. Leprosy - Six Hypo-pigmented Lesions + Nerve Thickening [NBMCH]

1. Provisional Diagnosis (1 mark)

2. WHO Classification (4 marks)

• 6 hypo-pigmented lesions (on back and extremities)
• Thickening of BOTH ulnar AND median nerves (2 nerves)

• Tuberculoid (TT) - Paucibacillary end
• Borderline tuberculoid (BT) - Paucibacillary
• Mid-borderline (BB)
• Borderline lepromatous (BL) - Multibacillary
• Lepromatous (LL) - Multibacillary end

3. Treatment Regimen - WHO MDT for MB Leprosy, Adults (4 marks)

• Duration: 12 monthly supervised doses.
• If clofazimine is unacceptable (skin discoloration), replace with Ethionamide 250-375 mg daily.
• Regular treatment = at least 8 out of 12 doses received.
• Patient is declared released from treatment (RFT) after completing the regimen.

4. Complications of Leprosy (3 marks)

• Peripheral neuropathy (ulnar, median, common peroneal, radial nerves)
• Loss of sensation (touch, pain, temperature)
• Muscle weakness and paralysis

• Grade 0: No anaesthesia, no visible deformity
• Grade 1: Anaesthesia present, no visible deformity
• Grade 2: Visible deformity/damage (claw hand, foot drop, wrist drop, lagophthalmos, blindness)

• Lagophthalmos (inability to close eye) - risk of corneal ulceration and blindness

5. Management of ENL Reaction (New Inflamed Red Nodules + Fever + Malaise) (3 marks)

• New inflamed red subcutaneous nodules on limbs/trunk
• High fever and severe malaise
• Original leprosy patches remain unchanged

1. Continue MDT - do NOT stop multidrug therapy.
2. Mild ENL: Aspirin or NSAIDs (analgesics/antipyretics) for symptom relief.
3. Severe ENL (as in this case - fever + severe malaise):
   • Prednisolone is the drug of choice: Start at 40-60 mg/day, taper over weeks.
   • Monitor for steroid side effects: peptic ulcer, hyperglycaemia, hypertension, reactivation of TB.
4. Clofazimine at higher doses (100 mg three times daily for 3 months, then taper) is also effective for ENL, but takes 4-6 weeks to act - never use as sole agent in severe ENL.
5. Thalidomide (where available and in males only): 100-400 mg/day - highly effective for severe ENL; absolutely contraindicated in women of childbearing age.

Source: Park's Textbook of Preventive and Social Medicine, pp. 369-377

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Q6. Leprosy - Hypopigmented Patches + Right Ulnar Nerve [JMNMCH]

a. Provisional Diagnosis with Justification (2 marks)

1. Hypopigmented/erythematous skin patch with loss of sensation - PRESENT (hypopigmented, well-defined patches with loss of sensation to touch and temperature)
2. Thickened peripheral nerve - PRESENT (right ulnar nerve thickened and tender)
3. Acid-fast bacilli on skin smear - not tested

• Tingling and numbness in hands (ulnar nerve involvement)
• No fever or weight loss (distinguishes from TB/lymphoma)
• 6-month history (chronic, indolent course)

b. Classification as per National Guidelines (2 marks)

• Skin lesions: hypopigmented patches over right arm and back - likely ≤5 lesions (not clearly stated as ≥6)
• Nerve: Right ulnar nerve only (single nerve involvement)

c. Treatment Regimen - PB Leprosy, National Programme (NLEP) (5 marks)

• Duration: 6 monthly supervised doses
• Patient is released from treatment (RFT) after 6 doses
• Surveillance period: 2 years for PB leprosy after RFT (patient monitored for relapse)
• Drugs are provided free of cost through the NLEP under ASHA/PHC network

• Rifampicin 450 mg monthly; Dapsone 50 mg daily

d. Preventive and Control Strategies (6 marks)

1. Early diagnosis and complete treatment - prevents progression and transmission
2. Self-examination for new skin lesions and nerve tenderness
3. Care of anesthetic limbs: use of protective footwear, gloves; daily inspection
4. Prevention of disability: Eye care (protective glasses, lubricating drops), physiotherapy
5. Adherence to MDT to avoid relapse and drug resistance

1. Active case detection: Survey of household contacts of leprosy patients; school surveys; population surveys in endemic areas
2. BCG vaccination: Provides 20-80% protection against leprosy
3. Chemoprophylaxis: Single-dose rifampicin (SDR) to close contacts of newly diagnosed PB leprosy cases (WHO recommendation - contact tracing programme)
4. Health education: Reduce stigma; spread awareness that leprosy is curable; early presentation campaigns
5. NLEP (National Leprosy Eradication Programme): Provision of free MDT at PHC level; training of health workers; Leprosy Case Detection Campaign (LCDC)
6. Disability prevention and rehabilitation: Reconstructive surgery camps; self-care groups; socioeconomic rehabilitation
7. Surveillance: Monitor elimination targets (<1 case per 10,000 population at district level)

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Q7. Cerebral Malaria - Forest Area Resident [JHARGRAM]

1. Probable Diagnosis (1 mark)

2. National Programme Covering Malaria (1 mark)

3. Other Diseases Under NVBDCP (2 marks)

1. Malaria
2. Filariasis (Lymphatic filariasis)
3. Kala-azar (Visceral Leishmaniasis)
4. Japanese Encephalitis (JE)
5. Dengue
6. Chikungunya

4. Management Protocol (5 marks)

• Admit to ICU/ward with close monitoring
• IV access - secure two large-bore IV lines
• Correct hypoglycaemia (check blood glucose urgently - IV 50% dextrose if needed)
• Airway management: Position patient in recovery position; intubate if GCS ≤8
• Manage convulsions: IV diazepam 0.15 mg/kg slow IV; prevent aspiration
• Treat hyperpyrexia: Paracetamol, tepid sponging (avoid aspirin)
• Correct severe anaemia (Hb <5 g/dL): Blood transfusion
• Manage renal failure: IV fluids carefully; dialysis if needed

• 2.4 mg/kg IV at 0, 12, 24 hours, then once daily
• Continue until patient can take oral medication, then switch to ACT oral therapy

• IV Quinine: Loading dose 20 mg/kg diluted in 5% dextrose over 4 hours, then 10 mg/kg every 8 hours
• Monitor for cinchonism (tinnitus, deafness) and hypoglycaemia during quinine therapy

• Complete course of oral Artemisinin Combination Therapy (ACT) - Artemether-Lumefantrine or AS+SP (artesunate + sulfadoxine-pyrimethamine) as per national guidelines
• Primaquine 0.75 mg/kg single dose as gametocytocidal (to prevent transmission)

5. Preventive Aspects Under NVBDCP (4 marks)

• Early case detection using Rapid Diagnostic Tests (RDT) or microscopy
• Complete treatment with ACT; directly observed treatment where needed
• Epidemic preparedness and rapid response

• Indoor Residual Spraying (IRS): DDT/malathion/synthetic pyrethroids in high-risk areas
• Insecticide Treated Bed Nets (ITBNs)/Long-Lasting Insecticidal Nets (LLINs)
• Anti-larval measures: Larvivorous fish (Gambusia, Guppy) in water bodies; temephos larvicide
• Source reduction: Elimination of mosquito breeding sites
• Minor environmental engineering (drainage, filling of stagnant water)

• Behaviour Change Communication (BCC)
• JE vaccination in endemic areas
• Mass Drug Administration (MDA) for filariasis
• Human resource capacity building

6. Surveillance Measures for Malaria (2 marks)

1. Passive Surveillance: Cases reported by health facilities; blood slides/RDTs from fever cases
2. Active Surveillance: House-to-house fever surveys by MPW/ASHAs in high-transmission areas; Mass Blood Survey (MBS)
3. Slide Positivity Rate (SPR) and Annual Parasite Incidence (API) calculated at PHC level
4. Epidemic preparedness: Sentinel sites; weekly reporting under IDSP (P and L forms)
5. Web-based MIS: Reporting to NVBDCP portal
6. District Malaria Officers (DMO) supervise surveillance; respond to outbreaks

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Q8. Dog Bite - District Hospital OPD, 2 Hours Post-Bite [DMGMCH]

1. WHO Exposure Category Classification (4 marks)

• Puncture wounds (2 punctured wounds = transdermal bites) on left leg
• The stray dog was unprovoked and ran away (cannot be observed)
• Mild bleeding present (implies skin breach)

• Stray dog (unvaccinated, unknown status)
• Unprovoked attack
• Dog ran away (cannot monitor for 10 days)
• Patient is a manual labourer (forest/outdoor exposure possible)

2. Immediate Local Wound Management (4 marks)

1. Flush and wash all wounds with soap and water under running tap for at least 15 minutes (use catheter for deep puncture wounds)
2. Apply virucidal agent - povidone-iodine solution or 70% alcohol or tincture of iodine
3. Do NOT suture immediately; if necessary, suture only after 24-48 hours with minimum stitches under RIG cover
4. Antibiotics: Amoxicillin-clavulanate 625 mg TDS x 5-7 days (prophylactic)
5. Tetanus prophylaxis: Tetanus toxoid 0.5 ml IM; tetanus immunoglobulin if not previously immunized
6. Document wound site, size, and depth

3. Post-Exposure Prophylaxis Schedule (5 marks)

• HRIG: 20 IU/kg, OR ERIG: 40 IU/kg
• Infiltrate into and around wound; remainder IM (distant from vaccine site)
• Give on Day 0 only

• Doses on Days 0, 3, 7, 14, and 28 (1 dose each day = 5 doses total)
• Inject into deltoid muscle (1 ml or 0.5 ml depending on vaccine type)
• Do NOT inject into gluteal region (poor antibody response)

4. Public Health Measures for Rabies Prevention at Community Level (2 marks)

1. Dog population management: Mass vaccination of dogs (target ≥70% vaccination coverage to achieve herd immunity in dog population); responsible pet ownership; stray dog management.
2. Public awareness: Educate communities on immediate wound washing after bites; know the nearest Anti-Rabies Centre (ARC); discourage abandonment of pets.

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Q9. Dog Bite - 14-Year-Old Boy [DHGMCH]

1. WHO Exposure Category and Justification (2 marks)

• Three bleeding puncture wounds (transdermal bites) - skin completely breached
• Scratch marks present (licks on broken skin = Category III)
• Stray dog, unprovoked, ran away
• Child has not washed the wound - no immediate decontamination

2. Immediate Wound Management (2 marks)

1. Flush wounds immediately with soap and water under running tap for at least 15 minutes (use syringe/catheter for puncture wounds - they are deep)
2. Apply povidone-iodine or 70% alcohol to wound
3. Do NOT suture immediately
4. Give tetanus toxoid (child's age/immunization status unknown; assume needed)
5. Give antibiotics (amoxicillin-clavulanate)

3. Post-Exposure Prophylaxis Indicated (2 marks)

• HRIG 20 IU/kg (or ERIG 40 IU/kg) - infiltrate into and around wounds on Day 0
• Cell culture vaccine: Essen regimen - Days 0, 3, 7, 14, 28 (IM deltoid)
• No prior vaccination history = full 5-dose course mandatory

4. Anti-Rabies Vaccination Schedules Under National Rabies Control Programme (2 marks)

1. Essen Regimen (IM, 5-dose): Days 0, 3, 7, 14, 28 (1 full dose IM deltoid each visit)
2. Zagreb Regimen (IM, 4-dose): Day 0 (2 doses - one each deltoid), Day 7, Day 21
3. 2-site Intradermal (ID) Regimen: 0.1 ml at 2 sites on Days 0, 3, 7, 28 (endorsement-dependent)
4. Previously vaccinated: Only Days 0 and 3 (2 doses IM/ID); no RIG

5. Four Fatal Clinical Features of Human Rabies (2 marks)

1. Hydrophobia - severe spasms of the throat muscles on attempting to drink water (pathognomonic)
2. Aerophobia - spasms triggered by a puff of air
3. Ascending paralysis (Paralytic/Dumb rabies form) - progressing to respiratory failure
4. Brainstem encephalitis - autonomic dysfunction, cardiac arrhythmias, respiratory arrest, coma

6. Four Community-Level Prevention and Control Measures (2 marks)

1. Mass vaccination of dogs - ≥70% dog population vaccinated to interrupt transmission
2. Stray dog management - humane control of stray dog population; responsible pet ownership legislation
3. Public health education - awareness campaigns on immediate wound washing, seeking care at ARCs; school-based education
4. Strengthening Anti-Rabies Centres (ARCs) - ensure free PEP availability at PHC/CHC level under National Rabies Control Programme; adequate stock of vaccine and RIG

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Q10. High Fever + Retroorbital Pain + Body Ache in 10-Year-Old [SMCH]

1. Probable Diagnosis (2 marks)

2. Laboratory Tests for Confirmation (3 marks)

3. Management (5 marks)

• Rest and adequate oral hydration (ORS, coconut water, fruit juices - 2-3 litres/day)
• Paracetamol for fever and pain (10-15 mg/kg/dose, 4-hourly; max 5 doses/day)
• Avoid: Aspirin, NSAIDs (ibuprofen), steroids (increase risk of bleeding and gastritis)
• Monitor platelet count daily once fever starts
• Warning signs requiring immediate hospitalization: severe abdominal pain, persistent vomiting, bleeding manifestations, rapid breathing, lethargy, restlessness, drop in platelet <50,000

• IV Fluid therapy: Start with Ringer's lactate 10 ml/kg/hour; titrate based on haematocrit and clinical response
• Monitor haematocrit every 4-6 hours; if rising despite fluids, suspect plasma leakage
• Platelet transfusion: Only if platelet <10,000 AND active bleeding (not routine for low platelet alone)
• Treat dengue shock syndrome (DSS): Colloids (dextran/starch) + aggressive IV fluids for shock; vasopressors if refractory
• Monitor urine output (target >0.5 ml/kg/hr)

4. Prevention of Dengue in the Locality (5 marks)

1. Source reduction (most important):
   • Empty, clean, and cover all water storage containers weekly
   • Drain flower vases, coolers, old tyres, overhead tanks
   • Introduce larvivorous fish (Gambusia) in ornamental ponds
   • Enforce civic bye-laws for mosquito breeding prevention
2. Larviciding: Apply temephos (Abate) to water containers that cannot be emptied
3. Biological control: Bacillus thuringiensis israelensis (BTi) as biological larvicide
4. Personal protection:
   • Use mosquito repellents (DEET-based)
   • Wear full-sleeved clothing (Aedes bites during day)
   • Use mosquito nets; window/door screens
5. Community mobilization:
   • Weekly "Dry Day" campaign - search and destroy all water-collecting containers
   • School/Anganwadi-based awareness programmes
   • ASHA/ANM surveillance for fever clusters
6. Health system measures:
   • Rapid dengue diagnosis at PHC level (NS1 RDT)
   • Sentinel surveillance sites under NVBDCP
   • Reporting of clusters to District Health Officer for rapid response

Source: Park's Textbook of Preventive and Social Medicine, pp. 291-300; NVBDCP dengue guidelines

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Q11. Malaria Epidemic - Rural Block, Monsoon Season [ESIC JOKA]

a. Definition of Epidemic (2 marks)

• The excess is usually determined statistically as more than two standard deviations above the mean endemic occurrence.
• For rare diseases (e.g., smallpox), even a single case may constitute an epidemic.
• An epidemic may be caused by a single agent or may be of complex aetiology, and may occur in a geographically confined area or spread widely.

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b. Steps in Investigation of This Malaria Epidemic (8 marks)

• Examine a sample of fever cases clinically
• Perform peripheral blood smear (thick and thin films) for malaria parasites - identify species
• Use Rapid Diagnostic Tests (RDT) for Plasmodium falciparum (HRP-2 antigen)
• Collect samples for lab confirmation; do not delay investigation

• Calculate the Annual Parasite Incidence (API) and compare with previous years for the same block/season
• If current case count clearly exceeds the expected baseline (epidemic threshold), confirm epidemic
• In the case of malaria in an endemic region during monsoon, a sudden surge >2 SD above mean confirms epidemic

• Map the entire affected rural block; identify all villages
• Determine total population by age, sex; enumerate families by their water exposure, occupation (farm workers), proximity to breeding sites

• Active case detection: House-to-house survey for fever cases in the past 14 days
• Prepare an epidemiological case sheet/line list for each case: name, age, sex, village, date of onset, travel history, occupation, ITN use, type of housing
• Review hospitalization records; contact private practitioners
• Case definition: Person residing in the affected block with fever (axillary temp ≥37.5°C) AND blood smear/RDT positive for malaria parasites, within the past 4 weeks

• Time: Plot an epidemic curve (date of onset vs. case count). A progressive rise during monsoon suggests propagated/seasonal epidemic. If sudden spike, consider point-source (water contamination unusual for malaria; more likely linked to breeding site development after rains)
• Place: Draw a spot map marking case homes relative to vector breeding sites (stagnant water, ponds, rice fields, construction sites). Identify high-risk villages.
• Person: Calculate attack rates by age, sex, occupation, use of ITBNs. Identify if any specific group (farm workers, migrants) is disproportionately affected

• The monsoon creates ideal breeding conditions for Anopheles mosquitoes
• Hypotheses: Increased vector density due to waterlogging/rice fields; seasonal migration of infected workers from high-endemic forest zones; lapse in vector control activities
• Test by: Entomological investigation - larval survey (larval density per 10 dips); adult mosquito collection (man-hour density); malaria parasite rate (MPR) calculation

• Early treatment of all confirmed cases with ACT
• Conduct emergency IRS (indoor residual spraying) in affected villages
• Distribute LLINs to households
• Anti-larval operations (temephos, BTi, Gambusia)
• Health education - seek early treatment for fever

• Report epidemic via IDSP (P-form daily; L-form for lab confirmed; S-form for weekly summary)
• Notify District CMO/DVBDC Officer/NVBDCP; seek additional resources if needed
• Maintain daily situation report

• Monitor weekly case counts to assess if epidemic curve is declining
• Reassess IRS coverage; check if LLIN distribution was adequate

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c. Vector Control Measures for Malaria (5 marks)

• Application of residual insecticide to interior walls and ceilings where mosquitoes rest
• Insecticides used: DDT (1 g/m²), Malathion, Synthetic pyrethroids (alphacypermethrin, deltamethrin)
• Schedule: Twice yearly in high-transmission areas (pre-monsoon and post-monsoon)
• Covers 80% of households in targeted areas

• Nets impregnated with pyrethroid insecticide (deltamethrin, permethrin)
• Dual action: Physical barrier + insecticidal kill of Anopheles mosquitoes
• Particularly effective for children and pregnant women; free distribution under NVBDCP

• Biological: Larvivorous fish (Gambusia affinis, Poecilia reticulata/Guppy) in permanent water bodies
• Chemical: Temephos (Abate) 50% EC in non-potable water; Paris green in rice fields
• Bacterial: Bacillus thuringiensis israelensis (BTi) - safe for drinking water sources
• Microbial: Bacillus sphaericus for polluted water

• Drainage of stagnant water, waterlogged areas, marshes
• Filling of borrow pits and low-lying areas
• Proper management of rice fields (intermittent irrigation); lining of irrigation canals
• Construction of properly sealed water storage facilities

• Use of mosquito repellents (DEET, pyrethroid coils)
• Full-sleeved clothing during evening hours (peak Anopheles biting time - dusk to dawn)
• Window and door screens
• Behaviour change communication on consistent bed net use

• Use of Bacillus strains
• Introduction of larvivorous fish in water bodies unsuitable for drainage

All answers sourced from: Park's Textbook of Preventive and Social Medicine (NVBDCP, Rabies, Leprosy, Epidemic Investigation, Dengue, IMNCI chapters); Harrison's Principles of Internal Medicine 22E; WHO Guidelines on Rabies PEP (2018).

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GROUP B - SAQ MODEL ANSWERS (10 Marks Each)

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Q1. Dengue Fever - Epidemiology, DHF Management, Integrated Vector Control [JNM] (2+4+4)

Epidemiological Determinants of Dengue Fever (2 marks)

• Causative agent: Dengue virus (Flavivirus) - 4 serotypes: DEN-1, DEN-2, DEN-3, DEN-4
• All four serotypes can cause dengue fever and DHF
• Secondary infection with a different serotype greatly increases DHF risk (antibody-dependent enhancement)
• No cross-protective immunity between serotypes; hyperendemicity (co-circulation of all 4 serotypes) is associated with DHF outbreaks

• All ages susceptible; children <5 years most severely affected in DHF
• Primary (first-time) infection = classic dengue fever
• Secondary (second-time, different serotype) = higher DHF/DSS risk
• Genetic susceptibility factors play a role
• India is in Category A - major public health problem with all 4 serotypes circulating

• Vector: Aedes aegypti (primary); Aedes albopictus (secondary)
• Aedes is a day-biting mosquito (peak biting: early morning and late afternoon)
• Breeds in clean, stagnant water in peridomestic containers (flower vases, tyres, coolers, water tanks)
• Favoured by tropical/subtropical climate, monsoon season, urbanization
• Season: peak during and after monsoon (July-November in India)
• Transmission: no animal reservoir; virus transmitted human-mosquito-human

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Clinical Management of Dengue Haemorrhagic Fever (4 marks)

1. Fever lasting 2-7 days
2. Haemorrhagic manifestations (positive tourniquet test, petechiae, ecchymoses, or bleeding)
3. Thrombocytopenia (platelet ≤100,000/mm³)
4. Plasma leakage evidence (haematocrit rise ≥20%, or pleural effusion/ascites)

• Strict monitoring: vital signs, urine output, haematocrit every 4-6 hours
• Paracetamol for fever; avoid aspirin and NSAIDs (risk of bleeding and gastritis)
• Adequate oral hydration: ORS/coconut water 2-3 litres/day if tolerating orally

• Start with Ringer's Lactate (RL) or Normal Saline 10 ml/kg/hour
• Titrate based on haematocrit and clinical response
• If haematocrit rising despite IV fluids: switch to colloids (dextran 40 or starch)
• Reduce IV fluids as patient improves (recovery phase - risk of fluid overload)
• Monitor for pleural effusion, ascites (chest X-ray/ultrasound)

• Aggressive IV fluid resuscitation: 20 ml/kg over 15-30 minutes
• Repeat if shock persists; switch to colloids if haematocrit not improving
• Vasopressors if refractory shock
• Correct metabolic acidosis; monitor lactate

• Only indicated if platelet <10,000/mm³ AND active significant bleeding
• NOT given prophylactically for low platelet counts alone

• Severe abdominal pain, persistent vomiting, rapid breathing, cold/clammy extremities, rapid deterioration at defervescence

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Integrated Vector Management (IVM) under NVBDCP (4 marks)

• Eliminate or modify mosquito breeding sites
• Empty and clean water containers (buckets, tanks, flower vases, coolers) weekly
• "Dry Day" campaign - community-level search and destroy
• Cover all water storage containers; dispose of old tyres, containers

• Introduce larvivorous fish (Gambusia affinis, Poecilia reticulata/Guppy) in ornamental ponds and water bodies
• Bacillus thuringiensis israelensis (BTi) - biological larvicide, safe for drinking water

• Larviciding: Temephos (Abate) 50% EC applied to water containers that cannot be emptied
• Adulticiding/Space spraying: Pyrethroid-based fogging/misting for rapid knockdown during outbreaks (emergency measure only)

• Insecticide-treated mosquito nets (though Aedes bites during day, nets help for sleeping infants)
• Repellents (DEET-based); full-sleeved clothing during peak biting hours
• Window and door screens

• Civic bye-laws enforced to prevent water stagnation
• Proper urban drainage; construction site management
• Enforcement of anti-mosquito regulations under Mosquito Breeding Act

• Behaviour Change Communication (BCC) campaigns
• Intersectoral convergence (municipalities + health departments)
• Surveillance: entomological indices (House Index, Breteau Index, Container Index)

Source: Park's Textbook of Preventive and Social Medicine, NVBDCP Chapter; pp. 291-303

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Q2. Emerging and Re-emerging Diseases [MMC] (2+2+6)

Definitions with Examples (2+2 marks)

1. HIV/AIDS - first recognized in 1981 among homosexual men in the USA
2. COVID-19 (SARS-CoV-2) - first recognized in Wuhan, China in 2019
3. Nipah virus - first recognized in Malaysia, 1998
4. SARS - first emerged in China, 2002-2003

1. Drug-resistant Falciparum malaria - reappearing in resistant phenotype
2. Cholera - reappeared in Haiti (2010) after disasters and mass migrations
3. Dengue - re-emerging with explosive outbreaks in new geographic areas
4. Tuberculosis - re-emergence particularly as multi-drug resistant (MDR-TB) and HIV-associated TB

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Factors Responsible for Resurgence (6 marks)

• Deforestation, land-use changes bring humans into contact with new animal reservoirs (zoonotic spillover)
• Climate change expands vector habitats (e.g., Aedes mosquitoes spreading to temperate zones)
• Floods, droughts create new breeding environments

• Urbanization with poor sanitation and overcrowding
• Population growth and migration (migrant workers carrying infections to new areas)
• Ageing populations (more immunocompromised individuals)

• Rapid jet-age travel can spread a pathogen globally before it is even recognized
• Global trade of food and animals (e.g., contaminated food, exotic pets)

• Genetic mutations enabling pathogens to evade immunity or resist drugs
• Acquisition of antibiotic/antiviral resistance (MDR-TB, drug-resistant malaria)
• Animal-to-human host switching (influenza pandemics, HIV from primates)

• Deterioration of surveillance and reporting systems
• Political instability, wars, and mass migrations disrupting health infrastructure
• Failure to maintain vaccination coverage (polio resurgence in parts of Africa)

• Intravenous drug use (HIV, hepatitis C)
• Sexual behaviour changes
• Consumption of bushmeat or exotic animals

• Blood transfusion and organ transplantation (HIV, hepatitis C historically)
• Use of immunosuppressive therapies (CMV, Pneumocystis)
• Food processing and distribution networks enabling foodborne outbreaks

• Deliberate release of anthrax spores (2001 USA attacks)

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Q3. Prolonged Fever + Splenomegaly + Anaemia + Leucopenia + Skin Darkening [MsdMCH] (2+4+5+4)

Provisional Diagnosis (2 marks)

• Prolonged fever >2 weeks (often with double daily spikes)
• Splenomegaly (massive, firm; most striking sign)
• Weight loss (significant, progressive)
• Skin darkening (kala-azar literally means "black fever" in Hindi/Bengali - due to hyperpigmentation)
• Anaemia (normocytic normochromic; due to hypersplenism and bone marrow infiltration)
• Leucopenia (leukocyte count progressively falls)
• Associated: hepatomegaly, hypoalbuminaemia, hypergammaglobulinaemia

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Laboratory Investigations for Confirmation (4 marks)

1. Splenic aspiration - Gold standard; sensitivity 93-99%; amastigotes (Leishman-Donovan bodies) seen on Giemsa-stained smear. Risk: bleeding (do only if platelets >40,000 and PT normal)
2. Bone marrow aspiration (sternal/iliac crest) - Sensitivity 54-86%; safer than splenic aspiration; Giemsa stain for amastigotes
3. Liver biopsy - Sensitivity ~86% but rarely done
4. Lymph node aspiration - Less sensitive but useful if nodes enlarged

• CBC: anaemia (Hb often <8 g/dL), leucopenia, thrombocytopenia
• LFT: raised bilirubin, low albumin, raised globulin
• Bone marrow biopsy: plasma cell infiltration

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Epidemiological Determinants of Kala-azar (5 marks)

• Causative organism: Leishmania donovani (obligate intracellular protozoan)
• Infective form: promastigotes (in sandfly); amastigotes/Leishman-Donovan bodies (in human macrophages)
• Primarily infects reticuloendothelial cells (macrophages in spleen, liver, bone marrow, lymph nodes)
• Incubation period: 2-6 months (range 10 days to 2 years)

• Sandfly - Phlebotomus argentipes (primary vector in India/South Asia)
• Small (2-3 mm), hairy, short-range flier (usually <200 metres)
• Breeds in cracks of walls, damp soil, animal burrows, leaf litter
• Bites at night (nocturnal feeder); females only bite
• Cannot survive above ground floor; affects ground-floor inhabitants

• Age: All ages affected; children 1-9 years and adults most affected
• Sex: Males slightly more affected
• Nutritional status: Malnutrition (particularly vitamin A and iron deficiency) increases susceptibility
• HIV co-infection: Dramatic increase in susceptibility to Kala-azar; AIDS-defining illness
• Occupational exposure: Agricultural and forestry workers who sleep outdoors

• Endemic in India: Bihar (70-80% of cases), Jharkhand, West Bengal, Uttar Pradesh
• Favoured environment: Humid, alluvial soil; dense vegetation; poor housing with mud walls
• Post-monsoon season: peak transmission September-January
• Annual rainfall and flooding favour sandfly breeding
• Socioeconomic: poverty, poor housing, lack of electricity (no fans to deter sandflies)

• In India: Man is the only reservoir (anthroponotic transmission - human to sandfly to human)
• In other regions (Brazil, China): dogs and rodents may be reservoirs

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Measures to Control the Vector (Sandfly) (4 marks)

1. Indoor Residual Spraying (IRS):
   • DDT 50% WP (1 g/m²) is most commonly used - two rounds per year (pre-monsoon + post-monsoon) in endemic areas
   • Alternative: Synthetic pyrethroids (deltamethrin, alphacypermethrin) where DDT resistance exists
   • Spray all interior walls, especially ground floor; ceilings; animal sheds
   • Phlebotomus argentipes rests on walls after feeding - highly susceptible to IRS
2. Long-Lasting Insecticidal Nets (LLINs):
   • Distribution to all eligible households in endemic districts
   • Fine-mesh nets required (sandflies smaller than mosquitoes)
3. Environmental Management:
   • Repair cracks and holes in mud walls and floors (eliminate breeding/resting sites)
   • Plaster walls; improve housing construction
   • Clear vegetation, leaf litter, debris near houses
   • Proper disposal of animal waste
4. Personal Protection:
   • Repellents (DEET); full-body clothing at night
   • Fans/air conditioning (sandflies avoid moving air)
   • Avoid sleeping on ground floor in endemic areas
5. Biological Control:
   • Limited options; some studies on neem-based repellents
6. Mass Drug Administration: Not used for Kala-azar specifically, but elimination target under NVBDCP: <1 case per 10,000 population at sub-district level

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Q4. NVBDCP Diseases + Dengue Epidemiology + Dengue Outbreak Control [MldMCH] (2+4+4)

Diseases Under NVBDCP (2 marks)

1. Malaria (Anopheles mosquito)
2. Filariasis - Lymphatic (Culex mosquito)
3. Kala-azar (Phlebotomus sandfly)
4. Japanese Encephalitis (Culex mosquito)
5. Dengue (Aedes mosquito)
6. Chikungunya (Aedes mosquito)

Epidemiology and Clinical Presentation of Dengue Fever (4 marks)

• Agent: Dengue virus (Flavivirus), 4 serotypes (DEN 1-4); all can cause DHF
• Vector: Aedes aegypti (day-biting); breeds in clean stagnant water in peridomestic containers
• Distribution: India is Category A (major problem; all 4 serotypes; urban + spreading to rural)
• Season: July-November (post-monsoon); incubation period 3-10 days
• Transmission: Human - Aedes - Human (no animal reservoir); transovarial transmission possible in mosquito

• Sudden onset high fever (39-40°C), intense headache
• Severe retro-orbital pain (on eye movement/pressure) - near pathognomonic
• Myalgia and arthralgia ("breakbone fever")
• Biphasic fever (brief remission followed by second febrile phase)
• Rash: maculopapular or scarlatiniform, on trunk spreading to extremities (80% cases); "islands of white in a sea of red"
• Nausea, vomiting, anorexia, altered taste

• Positive tourniquet test (≥20 petechiae per 1 inch²)
• Thrombocytopenia (≤100,000/mm³), rising haematocrit (≥20%)
• Plasma leakage: pleural effusion, ascites
• Progression to dengue shock syndrome (DSS) with circulatory failure

Measures to Control a Dengue Outbreak in a Town (4 marks)

1. Epidemiological investigation: Confirm outbreak; case definition; line listing; spot mapping
2. Emergency fogging/space spraying with pyrethroid insecticides for adult mosquito knockdown (emergency adulticiding)
3. Rapid case management: Set up dengue treatment corners at PHCs; ensure NS1 RDT availability; train staff

1. House-to-house survey: Entomological survey; destroy/empty all water-collecting containers
2. Targeted larviciding: Apply temephos (Abate) to containers that cannot be emptied
3. BTi application in overhead tanks and water bodies

1. "Dry Day" campaign weekly - community members empty/clean/cover all containers
2. School education: Students as change agents for source reduction at home
3. Awareness campaign: ASHA/ANMs + radio + megaphones on recognizing symptoms and seeking care

1. Intersectoral convergence: Engage municipalities, sanitation departments to improve drainage and remove garbage
2. Enforce Mosquito Breeding Prohibition Act: Issue notices to defaulters
3. Daily situation reporting to District Health Officer; report under IDSP
4. Strengthen entomological surveillance: Calculate House Index, Container Index, Breteau Index; set targets

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Q5. Single Face Bite by a Dog [KPC] (2+5+3)

Category of Bite (2 marks)

• It is a transdermal bite (skin is breached)
• Face is a high-risk location - highly vascularised, near CNS
• Short distance from face to brain means faster virus travel along nerve fibres
• Unprovoked bite by a street dog (unvaccinated, unknown status)

• Shorter incubation period (virus reaches CNS faster)
• Rich nerve supply to face
• PEP must be started immediately

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Management of This Case (5 marks)

1. Flush and wash wound immediately with soap and water under running tap for ≥15 minutes
2. Apply virucidal agent: povidone-iodine, tincture of iodine, or 70% alcohol
3. Do NOT suture immediately (if unavoidable, delay 24-48 hrs with RIG cover; minimum stitches)
4. Tetanus prophylaxis: Tetanus toxoid IM; TIG if not previously immunized
5. Antibiotics: Amoxicillin-clavulanate (prophylactic, given the site)

• Human RIG (HRIG): 20 IU/kg body weight, OR Equine RIG (ERIG): 40 IU/kg (skin test first)
• Infiltrate into and around the wound as much as anatomically possible
• Remaining RIG injected IM at a distant site from vaccine
• Given on Day 0 only (beyond Day 7 after first vaccine dose, RIG is not effective)
• Note for face bites: Infiltrate RIG meticulously around the entire wound; may need to dilute with saline to cover the wound

• Essen regimen (5-dose IM): Days 0, 3, 7, 14, 28 - deltoid muscle (1 ml or 0.5 ml per dose)
• OR Zagreb regimen: Day 0 (2 doses, one each deltoid), Day 7, Day 21
• Cell culture vaccine (PCECV/PVRV/HDCV) - do NOT use Semple's vaccine (nervous tissue)

• Observe the biting dog (if caught) for 10 days; if healthy throughout, PEP may be stopped
• Report to Anti-Rabies Centre and animal control authorities
• Given the face bite, consider hospitalization for monitoring

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Pre-Exposure Prophylaxis (PrEP) for Rabies (3 marks)

• Veterinarians, animal handlers, laboratory workers with rabies virus
• Wildlife officers, forest workers
• Long-term travellers to endemic areas (>30 days stay)
• Cave explorers (bat exposure risk)

• IM route: 1 dose (1 ml or 0.5 ml) on Days 0, 7, and 21 or 28 - 3 doses
• ID route: 0.1 ml at one site on Days 0, 7, and 21 or 28

• Routine boosters NOT required for general PrEP recipients
• For high-risk occupations: serological monitoring every 2 years (for laboratory workers, every 6 months); booster only if neutralizing antibody titre falls <0.5 IU/ml

• In the event of subsequent Category III exposure: only 2 booster doses (Days 0 and 3); NO RIG needed (already immune)

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Q6. Dengue Outbreak in a Town - Diagnosis, Investigation, NCVBDC Strategies [KPC] (1+5+4)

Most Likely Diagnosis (1 mark)

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How to Investigate This Outbreak (5 marks)

• Clinically examine the index case and a sample of reported cases
• Confirm with laboratory tests: NS1 antigen (Days 1-5), IgM antibody (from Day 5), RT-PCR for dengue RNA, and CBC (thrombocytopenia + leucopenia)
• Establish case definition: "Person in the locality with acute febrile illness (≥38°C) with ≥2 of: headache, retro-orbital pain, myalgia, rash, thrombocytopenia - onset within 3 weeks"

• Compare current case count with baseline for same locality and season
• With multiple similar cases in 2 weeks in one locality plus confirmed Aedes breeding, this confirms an outbreak

• Enumerate total population of the locality
• Obtain a map; mark case locations (spot map)

• House-to-house survey for fever cases in past 14 days
• Prepare line list: name, age, sex, address, date of onset, severity
• Contact hospitals, private practitioners for case counts

• Calculate House Index (% houses with Aedes larvae), Container Index, Breteau Index
• Identify the types of containers breeding Aedes (as already found)
• House Index >5% = high transmission risk; confirms vector link

• Epidemic curve: dates of onset - likely a progressive/propagated pattern
• Spot map: cluster around specific water sources or construction sites?
• Attack rate by house, age, sex

• Emergency adulticiding (fogging); source reduction campaign; larviciding

• Report outbreak under IDSP; notify District Health Officer; activate rapid response team

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Strategies under NCVBDC (formerly NVBDCP) for Dengue Prevention and Control (4 marks)

• Early case detection through sentinel hospitals and reporting under IDSP
• Free diagnosis (NS1 RDT) at government facilities
• Dengue treatment corners in government hospitals; training of physicians
• Referral systems for severe dengue

• Source reduction campaigns; "Dry Day" campaigns
• Larviciding with temephos; BTi
• Emergency space spraying during outbreaks
• Enforcement of civic bye-laws for water container management

• Regular calculation of Aedes indices (HI, CI, BI)
• Ovitrap surveillance for early warning
• Mapping of high-risk areas

• Community awareness: clean and cover containers weekly; wear protective clothing
• School-based education; media campaigns
• Health worker training (ASHA, ANM) on dengue recognition and vector breeding

• Insecticide resistance monitoring
• Dengue Vaccine (Dengvaxia is approved in some countries but with restrictions; India still evaluating)
• Strengthening diagnostic laboratory capacity

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Q7. Migrant Worker from Bihar - Prolonged Fever + Anaemia + Massive Splenomegaly [SSKM] (1+3+3+3)

Clinical Provisional Diagnosis (1 mark)

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Laboratory Diagnostic Methods (3 marks)

1. rK39 RDT (immunochromatographic strip test) - Point-of-care; sensitivity ~93%, specificity ~90%; recommended by NVBDCP as first-line; result in 10 minutes

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Clinical Management and Treatment (3 marks)

• Nutritional support (high protein diet; treat malnutrition)
• Blood transfusion if Hb <7 g/dL or symptomatic anaemia
• Treat any secondary infections (common due to immune suppression)
• Monitor renal, hepatic function

1. Liposomal Amphotericin B (AmBisome) - Drug of choice in India
   • Single dose: 10 mg/kg IV infusion OR
   • Multiple-dose regimen: 3-5 mg/kg/day for 5 days
   • Cure rate >97%; low nephrotoxicity; preferred in Bihar due to miltefosine resistance
2. Miltefosine (oral) - First oral drug for Kala-azar
   • 2.5 mg/kg/day orally for 28 days
   • Contraindicated in pregnancy; teratogenic
   • Cure rate 94-95% (declining due to resistance in Bihar)
3. Combination therapy (recommended to prevent resistance):
   • Liposomal AmBisome (single dose 5 mg/kg) + Miltefosine (28 days)
   • OR AmBisome + Paromomycin
4. Conventional Amphotericin B Deoxycholate (if liposomal not available):
   • 0.75-1 mg/kg IV every other day for 15-20 doses

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Public Health and Vector Control Measures (3 marks)

1. IRS with DDT (1 g/m²) - Two rounds annually in endemic blocks of Bihar/Jharkhand/WB
2. LLINs/fine-mesh nets distribution to all households in endemic districts
3. Active case detection - house-to-house surveys; rK39 testing; line listing
4. Case notification - mandatory reporting under NVBDCP elimination programme
5. PKDL management - PKDL cases are major reservoir; treat promptly
6. Improve housing: plaster mud walls; repair cracks (sandfly resting sites)
7. Environmental management: clear leaf litter, debris; improve drainage
8. Target: NVBDCP Kala-azar Elimination target = <1 case per 10,000 at sub-district (PHC) level

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Q8. Incubation Period + Cat II vs III + Cat III Management [NRS] (1+3+6)

Incubation Period Range for Human Rabies (1 mark)

• Site of bite: Shorter incubation for head, face, neck bites (closer to CNS); longer for lower extremities
• Severity of bite: Deep, multiple bites = shorter incubation
• Amount of virus inoculated: More virus = shorter incubation
• Host immunity: Prior vaccination extends incubation

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Differentiation: Category II vs Category III (3 marks)

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Complete Management of Category III Bite (6 marks)

• Wash with soap and water for ≥15 minutes under running tap; catheter for puncture wounds
• Apply virucidal: povidone-iodine or 70% alcohol
• No immediate suturing; tetanus prophylaxis; antibiotics

• HRIG: 20 IU/kg or ERIG: 40 IU/kg
• Infiltrate into/around wound on Day 0 only; remainder IM distant from vaccine
• Do not give beyond Day 7 after first vaccine

• Days 0, 3, 7, 14, 28 - IM deltoid
• Cell-culture vaccine (PCECV/PVRV); do not use Semple's/neural tissue vaccine

• If dog captured: observe for 10 days; if healthy, PEP may be discontinued

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Q9. Bridge Population + HIV Transmission + Prevention Strategies [RPHGMCH] (2+2+6)

Bridge Population (2 marks)

• Truck drivers (NACO categorizes truck drivers as bridge population - they have unprotected sex with female sex workers on highways AND with their regular spouses/partners at home)
• Migrant workers (move between urban areas with sex worker contact and rural homes)
• Clients of female sex workers
• Male partners of female sex workers

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Modes of Transmission of HIV (2 marks)

• Vaginal, anal, or oral sex with an infected partner
• Anal intercourse carries highest per-act risk
• Risk amplified by presence of STDs (8-10 times higher)
• Female-to-male less likely than male-to-female; anal more than vaginal

• Sharing of contaminated needles/syringes (IV drug users)
• Transfusion of infected blood or blood products (now rare with screening)
• Use of unsterilized surgical/dental equipment
• Needlestick injuries in healthcare workers

• During pregnancy (transplacental)
• During delivery (intrapartum - most common)
• Breastfeeding (postnatal)
• Without intervention: ~30-45% transmission rate

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Strategies for Prevention of HIV (6 marks)

1. ABC strategy: Abstinence; Be faithful (reduce partners); use Condoms
2. Free condom distribution - National AIDS Control Programme (NACP) via vending machines, health posts
3. Targeted interventions (TI) for high-risk groups (HRGs): sex workers, MSM, injecting drug users - through Targeted Intervention Projects (TIPs)
4. STI treatment - Treat STDs promptly (reduces HIV transmission 8-10 fold)
5. Behaviour Change Communication (BCC) - IEC campaigns; school health education; mass media
6. Pre-Exposure Prophylaxis (PrEP) - Tenofovir-based oral PrEP for high-risk uninfected individuals (now part of NACP)

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Q10. Migrant Worker + Low-grade Fever + Cough 4 Weeks + Weight Loss + Oral Thrush + Cervical Lymphadenopathy [RGKar] (5+2+3)

Screening and Diagnostic Algorithms (5 marks)

• National HIV testing algorithm (NACP): Three sequential ELISA/rapid tests using different antigens/formats
  • Test 1 (high sensitivity): If negative = HIV negative; if positive proceed to Test 2
  • Test 2 (high specificity): If positive proceed to Test 3; if negative = indeterminate
  • Test 3 (tiebreaker): If positive = HIV positive; if negative = indeterminate (repeat in 14 days)
• Western Blot (confirmation in indeterminate cases)
• HIV RNA PCR (for early diagnosis/window period; also for infant diagnosis <18 months)
• CD4 count - to stage the disease (WHO staging) and guide OI prophylaxis
• Viral load - baseline before ART initiation

• Sputum CBNAAT (GeneXpert MTB/RIF) - First-line; detects MTB and rifampicin resistance simultaneously; essential in HIV patients (higher sensitivity than smear)
• Sputum AFB smear (3 samples: spot-morning-spot) - Less sensitive in HIV (often smear-negative TB)
• Chest X-ray - May show atypical patterns in HIV-TB (lower lobe, military, no cavitation)
• Induced sputum or BAL if sputum not produced
• FNAC of lymph nodes if cervical lymphadenopathy prominent - caseous granulomas
• Sputum culture (MGIT/LJ medium) - Gold standard; 6-8 weeks result
• Mantoux test (TST) - Often falsely negative in HIV; not recommended alone

• Oral swab/culture for Candida (confirm oral thrush; determine species)
• Cryptococcal antigen (CrAg) serum test - if CD4 <100/mm³ (before starting ART)
• CMV retinitis screen - if CD4 <50
• LFT, RFT, CBC - Baseline before ART

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Why Traditional Diagnostic Approach Has Lower Sensitivity (2 marks)

1. Impaired cellular immunity (low CD4) means granuloma formation is defective - fewer AFB in sputum lesions (paucibacillary disease). Smear positivity falls as CD4 drops.
2. Mantoux/TST is anergy-based test - requires intact T-cell function; HIV destroys T-helper cells, so the test is frequently falsely negative even in active TB (energy to tuberculin antigen is lost).
3. Atypical radiological patterns in HIV-TB (no classic upper lobe cavitation); diagnosis missed on CXR alone.
4. Extrapulmonary/disseminated TB is more common in HIV (lymph node, pleural, miliary) - cannot be detected by standard sputum smear.

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Strategies for Treatment Adherence and Preventing Drug Resistance (3 marks)

1. Directly Observed Treatment (DOT) - Core strategy of RNTCP/NTEP; health worker or trained community observer watches patient swallow every dose; prevents irregular treatment
2. Fixed-Dose Combinations (FDCs) - Reduces pill burden; simplifies regimen; patient-friendly
3. Patient counselling at every visit: explain duration, side effects, and consequences of non-adherence (drug resistance, treatment failure, mortality)
4. Pill boxes and electronic medication reminders - Weekly pill boxes; mobile SMS reminders
5. Nikshay Poshan Yojana - Financial incentive (₹500/month) to TB patients for nutrition and adherence support under NTEP
6. Adherence supporters: Trained community volunteers; family members
7. Minimum wait times and patient-friendly services at treatment centres to reduce dropout
8. ART adherence: Enhanced adherence counselling (EAC) sessions before ART initiation; treatment literacy; peer support groups
9. Treat opportunistic infections promptly (poorly controlled OIs = reason for ART non-adherence)
10. Drug Susceptibility Testing (DST) at baseline to detect pre-existing resistance (especially RIF resistance by GeneXpert)

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Q11. Study Design - Alcohol and Dyslipidemia in Cooch Behar + Limitations + Nested Case-Control [MJNMCH] (8+2+2+3)

Study Design to Find Association Between Alcohol Consumption and Dyslipidemia (8 marks)

• Sampling frame: Household list from block health records / electoral rolls
• Sampling method: Multi-stage stratified random sampling
  • Stage 1: Select subcentres (strata = rural + urban/peri-urban areas)
  • Stage 2: Select households from each subcentre area by systematic random sampling
  • Stage 3: Select one eligible adult per household by Kish grid method

• Using formula: n = Z²pq/d²
• Estimate of dyslipidemia prevalence in alcohol users from literature (~40-50%)
• At 95% CI, 80% power, 5% absolute precision
• Add 10-20% non-response correction
• Estimated n ≈ 400-500 subjects

1. Interviewer-administered structured questionnaire - Sociodemographic details (age, sex, education, income, occupation); dietary habits; physical activity; comorbidities; drug history
2. Alcohol Assessment:
   • CAGE questionnaire (4-item screening)
   • AUDIT (Alcohol Use Disorders Identification Test) - gold standard for quantifying alcohol use
   • Assess: type of alcohol, frequency, quantity (units/week), duration of consumption
   • Categorize: Never drinker / Moderate drinker (<2 units/day men, <1 unit/day women) / Heavy drinker (>2 units/day)
3. Anthropometry: BMI, waist circumference (confounders)
4. Blood Pressure measurement
5. Fasting Lipid Profile (after 12-hr fast):
   • Total cholesterol (TC)
   • Triglycerides (TG)
   • HDL-cholesterol
   • LDL-cholesterol (Friedewald formula)
   • Dyslipidemia definition (NCEP ATP III):
     • TC ≥200 mg/dL, or LDL ≥130 mg/dL, or HDL <40 mg/dL (men)/<50 mg/dL (women), or TG ≥150 mg/dL, or being on lipid-lowering drugs

• Alcohol consumer: Anyone who has consumed any alcoholic beverage at least once in past 12 months
• Current drinker / Ex-drinker / Never drinker - clearly defined

• Descriptive: Prevalence of dyslipidemia overall and by alcohol category
• Analytical:
  • Chi-square test for proportions
  • Odds Ratio (OR) with 95% CI to measure association
  • Logistic regression to adjust for confounders (age, sex, BMI, diet, smoking, exercise, diabetes, medications)
• Ethical: Informed consent; IEC approval; confidentiality

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Limitations and Bias (2 marks)

1. Cross-sectional design cannot establish temporal relationship (cause-effect); cannot prove alcohol caused dyslipidemia
2. Recall bias - self-reported alcohol consumption may be under-reported due to social desirability (people under-report alcohol use)
3. Selection bias - voluntary participation may exclude heavy drinkers (who avoid health checkups)
4. Confounding - diet, exercise, BMI, diabetes, smoking all affect lipid levels; must be controlled in regression
5. Measurement bias - single fasting lipid profile may not represent usual values (day-to-day variation)
6. Seasonal variation - lipid levels vary with season; cross-sectional study captures one point in time

• Information bias/Recall bias - alcohol under-reporting
• Selection bias - non-response bias if heavy drinkers refuse to participate
• Observer bias - interviewers may probe differently based on perceived alcohol status

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Nested Case-Control Study (3 marks)

1. A cohort of disease-free individuals is assembled and followed over time (with baseline data and often stored biospecimens)
2. Over follow-up, some develop the disease of interest (cases)
3. For each case, a set of matched controls are selected from the same cohort (individuals who have not yet developed the disease at the time the matched case developed it)
4. The exposure status (and stored samples) of cases and matched controls are compared

• Exposure data collected before disease onset (prospective) - avoids recall bias
• Stored biospecimens can be tested selectively (cost-efficient compared to testing all cohort members)
• Cases and controls are from the same cohort - comparable baseline characteristics
• Efficient: does not require data collection from the entire cohort, only cases + selected controls
• Maintains temporal sequence (unlike cross-sectional studies)
• Compared to a traditional case-control: eliminates incidence-prevalence (Neyman) bias

• Biomarker studies within large cohort studies
• Exposure-disease studies where laboratory testing is expensive (e.g., stored blood for biomarker analysis)

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Q12. Infective Hepatitis Classification + Chronic Hepatitis B Management Algorithm [CNMCH] (2+8)

Classification of Infective Hepatitis (2 marks)

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Algorithm for Management of Chronic Hepatitis B (8 marks)

• HBsAg positive for ≥6 months
• Check: HBeAg, anti-HBe, HBV DNA (viral load), HBsAg quantification
• LFT (ALT, AST, bilirubin, albumin, PT), CBC, creatinine

• Liver biopsy (Metavir score) OR non-invasive tests:
  • FibroScan (transient elastography) - most widely used
  • APRI score (AST-to-Platelet Ratio Index)
  • FIB-4 score
• Significant fibrosis (F2 or above) or cirrhosis = treat regardless of ALT

• HBV DNA >2000 IU/mL + elevated ALT (>ULN) + significant fibrosis
• HBV DNA >20,000 IU/mL + elevated ALT (HBeAg+ active)
• Compensated cirrhosis with any detectable HBV DNA
• Decompensated cirrhosis (regardless of HBV DNA level)
• Special groups: Pregnancy (if HBV DNA >200,000 IU/mL, to prevent MTCT); immunosuppression; co-infection with HIV or HCV

• Lamivudine, Adefovir (high resistance rates; use only if above unavailable)

• 180 μg/week SC for 48 weeks
• Suitable for selected patients (young, HBeAg+, low viral load, high ALT, non-cirrhotic)
• Advantage: finite duration; may achieve HBsAg seroconversion
• Contraindicated: decompensated cirrhosis, pregnancy, autoimmune disease

1. HBV DNA suppression (undetectable) - primary goal with NA therapy
2. HBeAg seroconversion (HBeAg loss + anti-HBe development)
3. ALT normalization
4. HBsAg loss (functional cure) - occurs in <5% on NA therapy; 10-15% with IFN
5. Prevention of cirrhosis, decompensation, HCC

• HBV DNA every 3-6 months until undetectable, then every 6-12 months
• ALT every 3-6 months
• Annual AFP + ultrasound for HCC surveillance (all patients with cirrhosis; HBeAg+ males >40 years; others per guidelines)
• Renal function (TDF): creatinine, phosphate every 6-12 months

• NAs: Long-term (often lifelong) for HBeAg-negative CHB and cirrhosis
• HBeAg+ CHB on NA: Can stop 12 months after confirmed HBeAg seroconversion + HBV DNA undetectable (consolidation therapy)
• PEG-IFN: Fixed 48 weeks

• Pregnancy: TDF preferred (safe in pregnancy; reduces MTCT)
• HIV co-infection: TDF+3TC or TDF+FTC is backbone of ART (treats both)
• Prophylaxis for immunosuppression: Reactivation risk - screen all HBsAg/anti-HBc positive patients before chemotherapy; prophylactic ETV or TDF if high risk

Source: AASLD 2018 HBV Guidelines; EASL 2017; Harrison's Principles 22E

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Q13. 15-Month-Old Infant + ARI + RR 46/min + No Chest Indrawing + No Danger Signs [BGMCH] (5+5)

IMNCI Classification of ARI with Justification (5 marks)

• Convulsions? NO
• Lethargic/unconscious? NO
• Unable to drink/breastfeed? NO
• Vomits everything? NO
• → No General Danger Signs

• Respiratory rate: 46/minute (elevated?)

• Age 2-11 months: Fast breathing = RR ≥50/min
• Age 12 months - 5 years: Fast breathing = RR ≥40/min ← This child is 15 months
• RR 46/min in a 15-month child = FAST BREATHING (≥40/min)

• No chest indrawing present

• Not mentioned = absent

• Fast breathing (RR 46 ≥ 40 for age 12m-5y): YES
• Chest indrawing: NO
• General danger signs: NO

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Management According to IMNCI (5 marks)

• Amoxicillin (first-line): 40 mg/kg/day in 2 divided doses for 5 days
  • For 15-month child (~10-12 kg): approx 200-240 mg twice daily
• Alternative if penicillin allergy: Co-trimoxazole (though resistance is high - Amoxicillin preferred)

• Paracetamol for fever: 10-15 mg/kg/dose 4-6 hourly if temperature ≥38.5°C
• Encourage continued breastfeeding/oral fluids - do NOT restrict food or fluids
• Soothe the throat with a safe remedy (honey in older children; not <1 year)
• Do NOT give cough suppressants, antihistamines, or expectorants

• Give antibiotics as prescribed (complete the 5-day course even if child improves)
• Feed the child more frequently; give extra fluids
• Clear blocked nose if it interferes with feeding

• Child is breathing faster or more difficultly
• Chest indrawing develops (upgrade to Severe Pneumonia - refer urgently)
• Child cannot drink or is getting worse
• Convulsions occur
• Fever persists or child looks very sick

• Reassess in 2 days to check if improving
• At follow-up: count respiratory rate again, assess feeding and temperature
• If improving: complete 5 days of antibiotics
• If worse or no improvement → refer to hospital (possible antibiotic failure or Severe Pneumonia)

• Refer urgently to hospital
• Give first dose of oral amoxicillin before referral
• IV Ampicillin + Gentamicin in hospital

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Q14. Dengue Cases in a Block - Diagnosis and Control [BGMCH] (4+6)

Measures for Diagnosis (4 marks)

• Suspect dengue in: acute febrile illness (2-7 days) with ≥2 of: headache, retro-orbital pain, myalgia, arthralgia, rash, haemorrhagic manifestations, leucopenia
• Positive Tourniquet Test (≥20 petechiae/in²) supports diagnosis

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Control and Prevention Measures (6 marks)

1. Confirm outbreak via laboratory testing; establish case definition; prepare line list
2. Emergency space spraying/fogging - pyrethroid adulticiding throughout the block (rapid knockdown)
3. Set up dengue care corners at block PHC; train staff on dengue management; ensure availability of NS1 RDT, IV fluids, platelet monitoring
4. Report to District Health Officer; activate rapid response team; submit IDSP reports

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Q15. Signs, Symptoms, Diagnosis, and Management of Scrub Typhus [MCK] (2+2+2+4)

Signs and Symptoms (2 marks)

1. Eschar (pathognomonic) - painless, punched-out ulcer with black, necrotic centre + erythematous halo at the mite bite site (most commonly found in hidden moist areas: axilla, groin, genitals, behind ear)
2. Fever - high-grade, abrupt onset; lasts 2-3 weeks if untreated
3. Rash - maculopapular, starts on trunk, spreads to extremities (appears Day 5-7)

• Severe headache (constant, frontal)
• Generalized lymphadenopathy (regional + generalized)
• Myalgia, malaise
• Relative bradycardia
• Splenomegaly and hepatomegaly
• In severe disease: encephalitis, myocarditis, ARDS, acute renal failure

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Diagnosis (2 marks)

1. Weil-Felix reaction (OXK agglutination) - Screening test; titre ≥1:160 positive; not specific but widely available at peripheral labs; cross-reacts with Proteus mirabilis OXK
2. Indirect Immunofluorescence Assay (IFA) - Gold standard; fourfold rise in titre between acute and convalescent sera (2-4 weeks apart) confirms diagnosis
3. ELISA (IgM/IgG) - Sensitive; IgM positive from Day 5-10
4. PCR (eschar swab or blood) - Most sensitive in early disease; identifies species and genotype
5. Blood culture (microbiological isolation) - Reference standard but slow, specialized lab required
6. CBC: Leucopenia early; thrombocytopenia; elevated transaminases

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Management (4 marks)

• Doxycycline 100 mg twice daily orally for 7-15 days
• Defervescence occurs within 24-48 hours of starting treatment (dramatic response - diagnostic too)
• Continue for at least 3 days after fever subsides (minimum 7 days total)
• In children <8 years and pregnant women: Doxycycline is relatively contraindicated; use Azithromycin (500 mg on Day 1, then 250 mg Days 2-5)

• Chloramphenicol 500 mg QID for 7-10 days (where doxycycline unavailable; more side effects)
• Azithromycin (increasingly first-line especially in children and pregnancy)

• Antipyretics (paracetamol) for fever
• IV fluids for hydration
• Treat complications: mechanical ventilation for ARDS; dialysis for ARF; cardiac monitoring for myocarditis
• Secondary bacterial infection: appropriate antibiotics

• Avoid tall grass, scrubland (chigger habitat); wear protective clothing; DEET repellents
• Prophylaxis: Doxycycline 200 mg weekly for travelers to endemic areas (not routinely recommended for general population)

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Q16. Natural History of Disease with HIV/AIDS + Two Opportunistic Infections [ESIC JOKA] (7+3)

Natural History of Disease with HIV/AIDS as Example (7 marks)

• No disease yet; risk factors present (e.g., unprotected sex with HIV+ partner, sharing needles)
• Opportunity for Primary Prevention (BCC, condom use, PrEP, harm reduction)

• HIV exposure and infection - virus enters body and starts replicating
• Window period (2-12 weeks): HIV RNA detectable by PCR; antibodies NOT yet formed; standard antibody tests NEGATIVE; person is highly infectious
• Primary HIV infection (Acute Retroviral Syndrome): ~70% develop a mononucleosis-like illness: fever, sore throat, rash, lymphadenopathy, myalgia - resolves in 2-4 weeks
• Detection: 4th generation Ag/Ab combo assays detect p24 antigen during window period
• Opportunity for Secondary Prevention (early diagnosis by HIV testing)

• Most common and longest stage - lasts 5-10 years on average (2-15 years)
• Person is antibody positive (seropositive); appears healthy
• Persistent Generalized Lymphadenopathy (PGL) may be the only sign
• CD4 count gradually declining (normal 800-1200; starts declining toward <500)
• Highly infectious to others throughout this stage
• Viral load: Low to moderate; CD4 count determines stage

• Symptomatic HIV infection below the threshold of AIDS-defining illness
• CD4 typically 200-500/mm³
• Manifestations: unexplained fever >1 month, night sweats, chronic diarrhoea, weight loss (>10%), fatigue, oral thrush, herpes zoster, seborrheic dermatitis

• CD4 count <200 cells/mm³ (or AIDS-defining illness, regardless of CD4)
• CDC 1993 definition: HIV positive + CD4 <200 OR AIDS-defining condition
• Major AIDS-defining illnesses appear:
  • CD4 200-500: TB (most common in India), recurrent bacterial pneumonia, herpes zoster
  • CD4 100-200: Pneumocystis jirovecii pneumonia (PCP), cerebral toxoplasmosis
  • CD4 <100: Cryptococcal meningitis, CMV retinitis, Mycobacterium avium complex (MAC), Candida oesophagitis
• Natural history without treatment: Death from OI or AIDS-related cancer within 1-2 years of AIDS diagnosis

• ART dramatically alters natural history; CD4 recovers; viral load becomes undetectable
• Life expectancy approaches near-normal; AIDS-defining illnesses prevented
• U=U (Undetectable = Untransmittable): Person on effective ART with undetectable viral load cannot transmit HIV

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Two Opportunistic Infections (3 marks - 1.5 marks each)

• Causative organism: Pneumocystis jirovecii (previously P. carinii) - an atypical fungus
• CD4 threshold: Occurs at CD4 <200/mm³
• Presentation: Progressive exertional dyspnoea, non-productive dry cough, low-grade fever, hypoxia disproportionate to chest findings; onset insidious over weeks
• CXR: Classic "bilateral butterfly/bat wing" interstitial infiltrates; may be normal early
• Diagnosis: Bronchoalveolar lavage (BAL) with Giemsa/methenamine silver stain shows cysts; serum LDH elevated (non-specific); 1,3-β-D-glucan positive
• Treatment: Co-trimoxazole (TMP-SMX) IV 15-20 mg/kg/day (TMP component) for 21 days; add Prednisolone if PaO₂ <70 mmHg (reduces inflammation)
• Prophylaxis: TMP-SMX 1 DS tablet daily when CD4 <200/mm³

• Causative organism: Cryptococcus neoformans - an encapsulated yeast
• CD4 threshold: Occurs at CD4 <100/mm³ (usually <50)
• Presentation: Sub-acute onset meningitis: headache (often severe), fever, neck stiffness (may be absent in HIV), photophobia; altered sensorium in severe cases; papilloedema if raised ICP
• CSF findings: Elevated opening pressure (>200 mmH₂O), lymphocytic pleocytosis, elevated protein, low glucose; India ink stain shows "halo" encapsulated yeast; CSF CrAg positive
• Serum CrAg: Positive in >95% of cases; useful screening test (done when CD4 <100/mm³ before starting ART - IRIS prevention)
• Treatment:
  • Induction (2 weeks): Liposomal Amphotericin B 3-4 mg/kg/day IV + Flucytosine (5FC) 100 mg/kg/day orally
  • Consolidation (8 weeks): Fluconazole 400 mg/day
  • Maintenance: Fluconazole 200 mg/day (until CD4 >100 for 6 months on ART)
• Monitor ICP: Serial lumbar punctures to normalize opening pressure (a major cause of death is raised ICP)

All answers sourced from: Park's Textbook of Preventive and Social Medicine; Harrison's Principles of Internal Medicine 22E; Goldman-Cecil Medicine; WHO/NACP/NVBDCP guidelines