Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 331: Which strain is used for the chickenpox vaccine?

A. Edmonston Zagreb strain
B. Oka strain (Correct Answer)
C. 'Danish' 131
D. RA 27/3 strain

Explanation: **Explanation:** The **Oka strain** is the correct answer because it is the universally used live-attenuated strain for the Varicella (Chickenpox) vaccine. It was originally isolated from a 3-year-old boy (named Oka) in Japan and subsequently attenuated through serial passage in human embryonic lung cells and guinea pig embryo cells. It is used in both the monovalent varicella vaccine and the quadrivalent MMRV vaccine. **Analysis of Incorrect Options:** * **Edmonston-Zagreb strain:** This is a live-attenuated strain used for the **Measles** vaccine. It is often preferred in developing countries because it can be administered to infants as young as 6 months. * **'Danish' 1331:** This refers to the specific strain of *Mycobacterium bovis* used in the production of the **BCG (Bacillus Calmette–Guérin)** vaccine for Tuberculosis. * **RA 27/3 strain:** This is the standard strain used for the **Rubella** vaccine. The "RA" stands for Rubella Abortus, as it was isolated from the kidney of an aborted fetus following maternal rubella infection. **High-Yield Clinical Pearls for NEET-PG:** * **Vaccine Type:** Chickenpox vaccine is a **Live Attenuated** vaccine. * **Schedule:** Usually given at 12–15 months, with a second dose at 4–6 years. * **Post-exposure Prophylaxis:** The vaccine is effective if administered within **3 to 5 days** of exposure. * **Contraindication:** Like all live vaccines, it is contraindicated in pregnancy and severely immunocompromised individuals. * **Herpes Zoster:** A higher potency version of the Oka strain is used in the Zoster vaccine (Zostavax) to prevent Shingles in the elderly.

Question 332: All of the following are true about Oral Polio Vaccine (OPV) except:

A. It is a killed vaccine. (Correct Answer)
B. It is stored at sub-zero temperatures.
C. It provides intestinal and humoral immunity.
D. The main problem associated with it is residual neuro-virulence.

Explanation: **Explanation:** The correct answer is **A (It is a killed vaccine)** because the Oral Polio Vaccine (OPV), also known as the **Sabin vaccine**, is a **live-attenuated vaccine**, not a killed one. In contrast, the Inactivated Polio Vaccine (IPV), or Salk vaccine, is the killed variant. **Analysis of Options:** * **Option A (Correct):** OPV contains live-attenuated strains of the virus (Sabin types 1, 2, and 3) that replicate in the gut to induce immunity. * **Option B (Incorrect):** OPV is highly heat-sensitive. For long-term storage at the state or regional level, it must be kept at **sub-zero temperatures (-20°C)**. At the PHC level, it is stored between +2°C to +8°C. * **Option C (Incorrect):** Because OPV is administered orally, it replicates in the Peyer’s patches of the intestine, inducing **Local/Mucosal immunity (IgA)**. It also enters the bloodstream to produce **Humoral immunity (IgG)**. IPV primarily provides only humoral immunity. * **Option D (Incorrect):** A major drawback of OPV is its genetic instability. The attenuated virus can revert to a virulent form, leading to **Vaccine-Associated Paralytic Poliomyelitis (VAPP)** or **Vaccine-Derived Polioviruses (VDPV)**, known as residual neuro-virulence. **High-Yield NEET-PG Pearls:** * **Most Heat Sensitive Vaccine:** OPV (requires Vaccine Vial Monitor - VVM). * **Most Heat Resistant Vaccine:** Hepatitis B (or TT, depending on the options). * **Herd Immunity:** OPV provides herd immunity through "secondary spread" (shedding in feces), whereas IPV does not. * **Current Strategy:** India currently uses **Bivalent OPV (bOPV)** containing types 1 and 3, alongside **Fractional IPV (fIPV)**. Type 2 was removed (switched) globally in 2016.

Question 333: Which of the following may not be used as candidate vaccine(s) in Leprosy?

A. BCG Vaccine
B. Killer M.leprae + BCG Vaccine
C. M.indicus pranii
D. BCG Vaccine + M.vaccae (Correct Answer)

Explanation: **Explanation:** The question asks for the combination that is **not** used as a candidate vaccine for Leprosy. While several mycobacterial strains have been studied for cross-reactivity, the combination of **BCG + M. vaccae** is not a standard or recognized candidate vaccine for leprosy prevention in major clinical trials or national programs. **Analysis of Options:** * **BCG Vaccine (Option A):** It is the most widely studied vaccine for leprosy. It provides varying degrees of protection (20% to 80%) against leprosy due to the antigenic similarity between *M. tuberculosis* and *M. leprae*. * **Killed M. leprae + BCG (Option B):** This combination was extensively studied in trials (e.g., the ICRC trial in India). It aims to enhance the cell-mediated immune response specifically against *M. leprae* antigens. * **M. indicus pranii (Option C):** Formerly known as **Mw (Mycobacterium w)**, this is an indigenous vaccine developed in India. It is an approved immunotherapeutic and immunoprophylactic agent used as an adjunct to MDT in multibacillary leprosy. * **BCG + M. vaccae (Option D):** While *M. vaccae* has been researched for immunotherapy in tuberculosis and certain cancers, it is not a standard candidate vaccine for leprosy, especially not in combination with BCG for this specific purpose. **High-Yield Clinical Pearls for NEET-PG:** 1. **M. indicus pranii (Mw):** The first vaccine in the world for leprosy, developed by G.P. Talwar in India. 2. **ICRC Vaccine:** Developed at the Indian Cancer Research Centre, it uses a cultivable strain of *M. leprae*-like mycobacteria. 3. **Protective Efficacy:** BCG provides better protection against Leprosy than it does against Tuberculosis. 4. **MDT (Multi-Drug Therapy):** Remember that vaccines are considered "immunotherapy" (adjunct to MDT) or "immunoprophylaxis" (prevention).

Question 334: All of the following are postcoital contraception methods except?

A. Mifepristone
B. IUD
C. Levonorgestrel
D. Barriers methods (Correct Answer)

Explanation: **Explanation:** The core concept of **Emergency Contraception (EC)**, also known as postcoital contraception, is to prevent pregnancy *after* unprotected intercourse has occurred but *before* implantation. **Why "Barrier Methods" is the correct answer:** Barrier methods (condoms, diaphragms, cervical caps) are **preventative** measures used *during* intercourse to prevent sperm from entering the cervix. They have no mechanism to prevent pregnancy once unprotected intercourse has already taken place. Therefore, they cannot be used as a postcoital or emergency method. **Analysis of Incorrect Options:** * **Mifepristone (Option A):** An anti-progestogen that can be used as EC. A single low dose (10–25 mg) is highly effective if taken within 72–120 hours. * **IUD (Option B):** The **Copper-T (Cu-T 380A)** is the **most effective** method of emergency contraception. It can be inserted up to 5 days (120 hours) after unprotected sex and has a failure rate of less than 0.1%. * **Levonorgestrel (Option C):** The most commonly used hormonal EC (e.g., Pill 72). It works primarily by delaying ovulation. The standard dose is 1.5 mg as a single dose within 72 hours. **High-Yield NEET-PG Pearls:** 1. **Gold Standard/Most Effective EC:** Copper-T IUD. 2. **Yuzpe Regimen:** An older method using combined oral contraceptive pills (Ethinylestradiol + Levonorgestrel) in two doses, 12 hours apart. 3. **Ulipristal Acetate:** A selective progesterone receptor modulator (SPRM) effective up to 120 hours; it is currently considered the most effective *oral* EC. 4. **Time Window:** Most hormonal ECs are licensed for use within 72 hours, but Copper-T and Ulipristal are effective up to 120 hours (5 days).

Question 335: A 7-month-old child presents with chest indrawing and a respiratory rate of 65 breaths per minute. There are no danger signs. How is this condition classified?

A. Very severe pneumonia
B. Severe pneumonia (Correct Answer)
C. Pneumonia
D. Moderate pneumonia

Explanation: This question is based on the **Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines for the classification of cough and cold in children aged 2 months to 5 years. ### **Explanation of the Correct Answer** According to IMNCI criteria, a child is classified as having **Severe Pneumonia** if they present with: 1. **Chest indrawing** (subcostal retraction), OR 2. **Stridor** in a calm child. In this case, the 7-month-old child has chest indrawing. Even though the respiratory rate is elevated (65 bpm), the presence of chest indrawing automatically upgrades the classification from "Pneumonia" to "Severe Pneumonia." These cases require urgent referral and injectable antibiotics. ### **Analysis of Incorrect Options** * **A. Very Severe Pneumonia:** This classification is used when **General Danger Signs** are present (e.g., inability to drink/breastfeed, lethargy/unconsciousness, persistent vomiting, or convulsions). Since the question states there are "no danger signs," this is incorrect. * **C. Pneumonia:** This is classified by **Fast Breathing** alone (RR ≥50 in 2–12 months; RR ≥40 in 1–5 years) *without* chest indrawing or danger signs. * **D. Moderate Pneumonia:** This is not a standard category in the IMNCI classification system for respiratory infections. ### **High-Yield Clinical Pearls for NEET-PG** * **Fast Breathing Cut-offs:** * <2 months: ≥60 bpm (Classified as "Severe Disease") * 2–12 months: ≥50 bpm * 12 months–5 years: ≥40 bpm * **Treatment:** Severe Pneumonia requires the first dose of an appropriate antibiotic (e.g., Ampicillin/Gentamicin) and immediate referral. * **No Pneumonia:** If there is no fast breathing and no chest indrawing, it is classified as "Cough or Cold," managed with home care.

Question 336: Which of the following best estimates the burden of malaria?

A. Mosquito rate
B. Annual Parasite Incidence (API) (Correct Answer)
C. Parasite rate
D. Spleen Rate (SPR)

Explanation: ### Explanation **Correct Option: B. Annual Parasite Incidence (API)** **Why it is correct:** The **Annual Parasite Incidence (API)** is the most sensitive and reliable index used to estimate the burden of malaria in a community. It measures the number of confirmed malaria cases (positive for parasites) per 1,000 population per year. Under the National Vector Borne Disease Control Programme (NVBDCP), API is the primary criterion used to categorize areas for intervention strategies. An API of **2 or more** is the threshold used to define high-risk areas requiring intensified control measures like Indoor Residual Spraying (IRS). **Analysis of Incorrect Options:** * **A. Mosquito rate:** This measures vector density (e.g., Man-Hour Energy or House Index) rather than the actual disease burden in the human population. * **C. Parasite rate:** This is a point-prevalence measure (percentage of people with parasites in their blood at a specific time). While useful for mapping endemicity, it does not capture the annual incidence or total burden as accurately as API. * **D. Spleen Rate (SPR):** Historically used to measure malaria endemicity in children (ages 2–9), it is now considered less reliable due to other causes of splenomegaly and the impact of rapid treatment. **High-Yield NEET-PG Pearls:** * **API Formula:** (Confirmed cases during the year / Total population under surveillance) × 1000. * **Annual Blood Examination Rate (ABER):** Measures the efficiency of the surveillance system. For a malaria program to be effective, the ABER should be at least **10%**. * **Slide Positivity Rate (SPR):** (Total positive slides / Total slides examined) × 100. * **Slide Falciparum Rate (SFR):** (Total P. falciparum positive slides / Total slides examined) × 100. * **Elimination Target:** India aims to be malaria-free by **2030**.

Question 337: Which of the following statements is FALSE regarding antigenic drift?

A. Occurs under pressure for immunity
B. Is responsible for epidemics of influenza
C. Occurs only in influenza A (Correct Answer)
D. Occurs every 10-12 years

Explanation: **Explanation:** The core concept in Influenza epidemiology is the distinction between **Antigenic Drift** and **Antigenic Shift**. **Why Option C is the correct (False) statement:** Antigenic drift refers to minor, gradual changes in the surface glycoproteins (Hemagglutinin and Neuraminidase) due to point mutations. This process occurs in **both Influenza A and Influenza B**. In contrast, Antigenic Shift (major genetic reassortment) occurs **only in Influenza A**, as it involves the exchange of gene segments between different strains (often involving animal reservoirs), which Influenza B lacks. **Analysis of other options:** * **Option A (True):** Drift occurs under "immunological pressure." As the population develops antibodies to a specific strain, the virus undergoes minor mutations to evade this pre-existing immunity. * **Option B (True):** Because drift results in new variants that the population is only partially immune to, it is responsible for **annual/periodic epidemics**. (Shift, conversely, causes pandemics). * **Option D (True):** While minor mutations happen frequently, significant drift that necessitates a change in the vaccine composition typically occurs every few years (classically cited as 10–12 years in epidemiological patterns for major epidemic cycles). **High-Yield Clinical Pearls for NEET-PG:** * **Antigenic Drift:** Minor change, point mutations, occurs in A & B, causes **Epidemics**. * **Antigenic Shift:** Major change, genetic reassortment, occurs **only in A**, causes **Pandemics**. * **Vaccine Implications:** Antigenic drift is the reason why the WHO updates the Influenza vaccine composition annually. * **Influenza C:** Usually causes mild respiratory illness and does not cause epidemics.

Question 338: The amount of sewage flowing in a system in 24 hours is called?

A. Sewage rate
B. Dry weather flow (Correct Answer)
C. RCA index
D. Sewage index

Explanation: ### Explanation **Correct Answer: B. Dry weather flow** **Why it is correct:** In environmental sanitation and public health engineering, **Dry Weather Flow (DWF)** is defined as the total quantity of sewage (domestic waste and industrial effluents) flowing through a sewerage system in a 24-hour period during dry weather. It excludes rainwater or surface runoff. DWF is a critical parameter for designing sewage treatment plants (STPs) and sewer pipes, as it represents the baseline load the system must handle daily. **Analysis of Incorrect Options:** * **A. Sewage rate:** This is a non-standard term in community medicine. While "rate" usually implies volume per unit of time, it is not the formal technical term used to describe the 24-hour flow. * **C. RCA index:** The Research-cum-Action (RCA) project is associated with the design of the **RCA latrine** (a hand-flush, water-seal pit privy) suitable for rural India. It is not a measure of sewage volume. * **D. Sewage index:** This is a distractor. While "indices" exist for water quality (like the BOD or COD), there is no standard "Sewage Index" used to measure 24-hour flow volume. **High-Yield Facts for NEET-PG:** * **Sullage:** Wastewater from kitchens and bathrooms that does **not** contain human excreta. * **Sewage:** Wastewater that **contains** human excreta (sullage + excreta). * **BOD (Biochemical Oxygen Demand):** The most important indicator of organic pollution in sewage. A high BOD indicates high pollution. Standard BOD is measured at **20°C for 5 days**. * **Modern Sewage Treatment:** Involves Primary (Physical), Secondary (Biological), and Tertiary (Chemical) treatment. The **Secondary treatment** (e.g., Trickling filter or Activated Sludge Process) is where the BOD is significantly reduced.

Question 339: Which of the following serogroups is NOT covered by the meningococcal quadrivalent vaccine?

A. A
B. Y
C. W135
D. G23 (Correct Answer)

Explanation: **Explanation:** The correct answer is **D (G23)**. Meningococcal disease is caused by the bacterium *Neisseria meningitidis*. While there are 13 known serogroups based on the composition of the capsular polysaccharide, only six (**A, B, C, W-135, X, and Y**) are responsible for the majority of invasive diseases (meningitis and septicemia) worldwide. The **Quadrivalent Meningococcal Vaccine** (available as both polysaccharide and conjugate forms, e.g., Menactra, Menveo) is specifically designed to provide protection against the four most common pathogenic serogroups: **A, C, W-135, and Y**. Serogroup **G23** is not a recognized pathogenic serogroup of *N. meningitidis* and is not included in any standard vaccine formulation. **Analysis of Options:** * **Option A (A):** One of the primary causes of epidemics in the "African Meningitis Belt." It is a core component of the quadrivalent vaccine. * **Option B (Y):** Frequently associated with meningococcal pneumonia and is covered by the quadrivalent vaccine. * **Option C (W135):** Associated with Hajj-related outbreaks and international travel; it is a standard component of the quadrivalent vaccine. **High-Yield Clinical Pearls for NEET-PG:** * **Vaccine Composition:** Quadrivalent vaccines cover **A, C, Y, W-135**. * **Serogroup B:** Not included in the quadrivalent vaccine because its capsular polysaccharide is poorly immunogenic (resembles human neural cell adhesion molecules). A separate protein-based vaccine (Bexsero/Trumenba) is used for Serogroup B. * **Hajj Requirements:** Vaccination with the quadrivalent (ACYW135) vaccine is mandatory for pilgrims traveling to Hajj/Umrah. * **Chemoprophylaxis:** **Rifampicin** is the drug of choice for close contacts; Ciprofloxacin or Ceftriaxone are alternatives.

Question 340: Which of the following statements is NOT true regarding Japanese encephalitis?

A. Approximately 80% of patients are children below 5 years of age.
B. During epidemics, cases are scattered, with no more than 1-2 cases per village.
C. The ratio of asymptomatic to apparent cases is approximately 1:100.
D. A bite from an infected mosquito always leads to the disease. (Correct Answer)

Explanation: **Explanation:** Japanese Encephalitis (JE) is a viral zoonosis caused by a Group B Arbovirus (Flavivirus). Understanding its epidemiological pattern is crucial for NEET-PG. **1. Why Option D is the Correct Answer (The False Statement):** A bite from an infected mosquito does **not** always lead to clinical disease. In fact, JE is characterized by a high rate of subclinical infection. Most individuals bitten by an infected *Culex* mosquito develop an inapparent infection and subsequent immunity without ever showing neurological symptoms. **2. Analysis of Other Options:** * **Option A:** JE is primarily a disease of children. In endemic areas, repeated exposure leads to natural immunity in adults, leaving children (especially those under 5–15 years) as the most vulnerable group. * **Option B:** JE exhibits a "scattered" or "sporadic" distribution. Unlike many other outbreaks, it is rare to see multiple cases in a single household or village because the primary cycle is between mosquitoes, pigs, and birds; humans are merely "dead-end" hosts. * **Option C:** The ratio of overt disease to asymptomatic infection is estimated to range from **1:250 to 1:1000** (though 1:100 is often cited in older texts as a baseline for "iceberg" visualization). This confirms that clinical cases represent only the "tip of the iceberg." **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** *Culex tritaeniorhynchus* (breeds in stagnant water/rice fields). * **Reservoir/Amplifier Host:** Pigs (the most important amplifier host) and Ardeid birds (herons/egrets). * **Dead-end Hosts:** Humans and Horses (viremia is insufficient to infect more mosquitoes). * **Vaccination:** The **SA-14-14-2** (Live attenuated) vaccine is used under the Universal Immunization Programme (UIP) in India, given at 9 months and 16–24 months.

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