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Nepal Medical College — Community Medicine (June 2019)

Complete Solutions

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SHORT ANSWER QUESTIONS (SAQ)

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Q1. Enumerate vector-borne diseases in Nepal. Discuss prevention & control of Kalaazar in Nepal. (2.5+2.5)

1. Enhanced Case Detection & Treatment
   • Quarterly active case searches ("Kala-azar Fortnight") - door-to-door by peripheral health workers
   • Use of rK39 rapid diagnostic test (RDT) - result within 5 minutes; simple, field-applicable
   • Treatment with Miltefosine (oral) or Liposomal Amphotericin B (single IV dose 10 mg/kg) - supplied free by WHO
   • PKDL (Post Kala-azar Dermal Leishmaniasis) detection and treatment to reduce human reservoir
2. Vector Control (Sandfly Control)
   • Indoor Residual Spraying (IRS) - DDT being replaced by synthetic pyrethroids (due to sandfly resistance)
   • Use of insecticide-treated bed nets
   • Environmental management - clearing of bushes near houses, plastering of mud walls
3. Surveillance & Monitoring
   • Sentinel surveillance sites
   • Regular monitoring and evaluation
4. Intersectoral Convergence & Behaviour Change Communication (BCC)
   • Community education on sandfly bite prevention
   • ASHA incentivized: Rs.300 for each detected case, Rs.100-200 for ensuring insecticide spraying rounds
5. Capacity Building
   • Training of health workers at peripheral level

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Q2. Differentiate between paucibacillary and multibacillary leprosy. Outline strategy for National Leprosy Control Program in Nepal. (2.5+2.5)

1. Early detection - passive surveillance, voluntary reporting; active surveys in high-endemic areas
2. MDT provision - free multi-drug therapy to all registered patients (ensures adherence)
3. Disability prevention - Self-care training for patients with Grade 1/2 disability; physiotherapy
4. Rehabilitation - social, economic, and physical rehabilitation of cured patients
5. IEC (Information, Education, Communication) - destigmatization campaigns
6. Integration into general health services - leprosy services embedded in primary health care
7. Elimination goal - <1 case per 10,000 population (achieved at national level; focus now on sub-district elimination)
8. BCG vaccination - provides ~50% protection against leprosy

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Q3. What is Drug dependency? Write briefly on epidemiological determinants of drug dependency. (2+3)

• Pharmacological properties: drugs with rapid onset, high euphoria potential (e.g., heroin, cocaine)
• Availability and accessibility of the drug
• Route of administration: IV route causes faster dependence than oral
• Type of drug: opioids, cannabinoids, amphetamines, sedatives, alcohol, cocaine, hallucinogens, tobacco, volatile solvents (ICD-10 classification)

• Age: adolescents and young adults are most vulnerable (peer pressure, curiosity)
• Sex: males more commonly affected
• Personality: individuals with antisocial personality, impulsiveness, low self-esteem
• Mental illness: depression, anxiety, schizophrenia - dual diagnosis
• Family history: genetic predisposition; children of addicts at higher risk
• Prior drug use: early initiation of tobacco/alcohol predisposes to harder drugs ("gateway" drugs)
• Ignorance about consequences

• Peer group pressure - the most common precipitating factor in youth
• Broken homes, family disharmony, domestic violence
• Poverty and unemployment - economic stress
• Urbanization and rapid social change - breakdown of traditional values
• Easy drug availability - proximity to drug trafficking routes (Nepal's position between India and China)
• Mass media and pop culture influence
• Weak law enforcement against drug peddling

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Q4. List the vaccines of National Immunization Program and mention dose, mode of administration and schedule of those vaccines. (5)

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Q5. What is meant by "concentrated epidemic" and "generalized epidemic" of HIV infection? Write briefly on trend of HIV infection in Nepal from year 2000 AD. (3.5+1.5)

• HIV prevalence is >5% in at least one high-risk sub-population (e.g., IDUs, sex workers, MSM, truckers)
• But remains <1% in general population (antenatal women)
• Transmission is concentrated within networks of high-risk behaviour
• Nepal's current status - concentrated epidemic pattern
• Requires targeted interventions in high-risk groups

• HIV prevalence is >1% among antenatal clinic (ANC) attendees (general population)
• HIV has spread beyond high-risk groups into the general population
• Heterosexual transmission dominates
• Common in sub-Saharan Africa
• Requires broad population-level interventions

• Nepal identified its first HIV case in 1988
• The epidemic grew during the 1990s-2000s, driven by IDU (Injecting Drug Users), migrants, and sex workers
• Peak prevalence was reached around 2003-2005 (estimated ~70,000 PLHIV)
• Since 2005, new infections have been declining due to targeted harm reduction programs, STI/HIV interventions
• By 2019: estimated ~32,000 people living with HIV; annual new infections ~2,200; AIDS deaths declining
• Major transmission routes: heterosexual contact (majority), IDU, mother-to-child (MTCT)
• Nepal has achieved "concentrated epidemic" status - prevalence highest among IDUs (~5-6%), FSW, migrants, MSM
• ART program scaled up; Nepal targets 90-90-90 goals (UNAIDS)
• Declining trend attributed to: condom promotion, needle-syringe exchange programs, PMTCT programs, ART access

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Q6. Write short notes on: (a) Normal Distribution Curve (b) Binomial Probability Distribution (2.5+2.5)

• Symmetrical, bell-shaped curve around the mean
• Mean = Median = Mode (all equal, located at center)
• The curve is defined by two parameters: mean (μ) and standard deviation (σ)
• Total area under the curve = 1 (or 100%)
• 68-95-99.7 Rule:
  • Mean ± 1 SD = 68.27% of observations
  • Mean ± 2 SD = 95.45% of observations
  • Mean ± 3 SD = 99.73% of observations
• Tails extend to infinity but never touch the x-axis (asymptotic)
• Skewness = 0; Kurtosis = 3

• Reference range determination (normal values)
• Z-score calculation: Z = (X - μ) / σ
• Statistical tests (t-test, ANOVA) assume normality
• Growth charts for children

1. There are a fixed number of independent trials (n)
2. Each trial has only two possible outcomes (success/failure, diseased/healthy)
3. The probability of success (p) is constant across trials
4. Trials are independent

• Mean = np
• Variance = npq
• Standard deviation = √(npq)
• When n is large and p is small → approximates Poisson distribution
• When n is large and p is not extreme → approximates Normal distribution

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PROBLEM-BASED QUESTIONS (PBQ)

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Q7. 45-year-old factory worker, cement factory, 25 years. Irritant cough, chest pain, dyspnoea on exertion. CXR: "snow storm" appearance. Sputum: no acid-fast bacilli.

1. Occupational exposure: Worked in a cement factory for 25 years - long-term inhalation of crystalline silica (SiO₂) dust
2. Classical symptoms: Insidious onset of progressive dyspnoea on exertion, cough, chest pain - typical of pneumoconiosis
3. CXR finding: "Snow storm" appearance = multiple nodular opacities in both lung fields - pathognomonic of silicosis; also described as "egg-shell" calcification of hilar lymph nodes in silicosis
4. Negative sputum for AAFB: Excludes active pulmonary tuberculosis as primary diagnosis (though silicosis greatly increases TB risk - "silicotuberculosis")
5. Duration: 25 years exposure in a dusty industry is consistent with chronic silicosis (develops after >10 years)

1. Engineering controls (Primary prevention):
   • Substitution: Replace silica with less hazardous material where possible
   • Enclosure and isolation: Enclose dusty processes
   • Wet methods: Use water sprays to suppress dust during drilling, cutting, grinding
   • Local exhaust ventilation (LEV): At source of dust generation
   • General ventilation: Adequate workshop ventilation
2. Administrative controls:
   • Job rotation: Limit individual exposure duration
   • Pre-employment medical examination: Baseline CXR, spirometry; exclude those with pre-existing lung disease
   • Periodic medical surveillance: Annual CXR and lung function tests (FEV1, FVC)
   • Dust monitoring: Regular measurement of silica dust levels; ensure below TLV (Threshold Limit Value: 0.1 mg/m³ for crystalline silica)
   • Health education: Educate workers about silicosis risk and importance of controls
3. Personal Protective Equipment (PPE):
   • Appropriate respirators (N95 minimum; P100 for high-exposure tasks)
   • Note: PPE is the last resort, not a substitute for engineering controls
4. Regulatory/Legal:
   • Enforce Factories Act / Occupational Safety and Health regulations
   • Compensation under workers' compensation laws

1. Economic consequences:
   • Loss of income: Patient was the sole earner; inability to work means complete loss of family income
   • Medical expenses: Costly investigations, long-term treatment, oxygen therapy - can push family into debt/poverty
   • Loss of assets: Family may sell assets to meet treatment costs
   • Child's education: Children (2 children) may have to drop out of school due to financial hardship
2. Social consequences:
   • Dependency: Entire family becomes dependent on others (relatives, social welfare)
   • Psychosocial stress: Anxiety, depression in patient and family members; marital strain
   • Stigma: Social stigma associated with occupational disease/disability
   • Role reversal: Wife may need to take up labour/domestic work to earn income
   • Isolation: Reduced social participation due to disease and poverty
3. Health consequences on family:
   • Malnutrition: Inadequate food security affects children's nutrition
   • Reduced healthcare access: Inability to afford healthcare for other family members
   • Psychological trauma in children

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Q8. 30-year-old male, Province 5 (Terai), fever, chills, rigors. Blood smear: Plasmodium parasite.

• Most likely Plasmodium vivax malaria (most common in Nepal Terai)
• Possible P. falciparum (must be ruled out as medical emergency)

1. Geographic: Province 5, Terai region - malaria-endemic zone of Nepal (low-altitude, warm, humid, abundant Anopheles breeding sites)
2. Classical presentation: Fever + chills + rigors = malarial paroxysm - caused by rupture of RBCs releasing merozoites
3. Blood smear positive: Demonstrates Plasmodium parasites - confirmatory finding
4. Season: Malaria is most common during/after monsoon (June-November) in Nepal Terai

1. API (Annual Parasite Incidence) = (Confirmed malaria cases per year / Total population at risk) × 1,000
   • Most important indicator for malaria burden; used to classify endemic levels
2. SPR (Slide Positivity Rate) = (Positive slides / Total slides examined) × 100
3. ABER (Annual Blood Examination Rate) = (Blood slides examined / Population) × 100 (target: >10%)
4. AMR (Annual Malaria Rate) = (Total malaria cases / Population) × 1,000
5. Parasite Index (PI) = (% of population with parasitaemia) - determined by survey
6. Proportional case fatality rate: Deaths / Confirmed cases
7. Spleen rate: % of children 2-9 years with palpable spleen (historical indicator, used in surveys)

• Insecticide-treated bed nets (ITNs/LLINs) - most effective personal protection
• Repellents (DEET), protective clothing (long sleeves/pants), especially at dusk and dawn
• Chemoprophylaxis for travelers entering endemic areas (Chloroquine in sensitive zones)

• Indoor Residual Spraying (IRS) with insecticides (DDT, Malathion, Synthetic pyrethroids)
• Larval source management: drainage of stagnant water, larviciding (Temephos, Bacillus thuringiensis israelensis)
• Biological control: introduction of larvivorous fish (Gambusia, Guppy)
• Environmental management: filling of burrow pits, improving drainage

• Universal access to diagnosis and treatment (slide microscopy + RDT)
• ASHA/health worker training for early case detection
• Nepal Malaria Strategic Plan (targets elimination by 2026)

• Chloroquine 25 mg/kg over 3 days (10 mg/kg Day 1 & 2, 5 mg/kg Day 3)
• Plus Primaquine 0.25 mg/kg/day × 14 days (for radical cure - eliminates hypnozoites; check G6PD status first)

• Artemisinin-based Combination Therapy (ACT): Artemether-Lumefantrine (first line in Nepal) × 3 days
• Plus Primaquine single dose (0.75 mg/kg) on Day 1 as gametocytocide

• IV Artesunate (first choice) or IV Quinine
• Supportive care: IV fluids, anti-pyretics, blood transfusion if severe anaemia
• Management of complications: cerebral malaria (mannitol for ICP), severe anaemia, acute renal failure, hypoglycaemia

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