Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 381: Which one of the following rickettsial diseases is transmitted by lice?

A. Epidemic typhus (Correct Answer)
B. Rocky Mountain spotted fever
C. Q fever
D. Endemic typhus

Explanation: **Explanation:** The correct answer is **Epidemic typhus**. This disease is caused by the bacterium *Rickettsia prowazekii* and is classically transmitted by the **human body louse** (*Pediculus humanus corporis*). It typically occurs in crowded, unsanitary conditions such as refugee camps or war zones. **Analysis of Options:** * **Epidemic typhus (Correct):** Transmitted by the body louse. A unique feature is that the louse dies from the infection, and transmission occurs when louse feces (containing the bacteria) are rubbed into bite wounds or mucous membranes. * **Rocky Mountain spotted fever:** Caused by *Rickettsia rickettsii* and is transmitted by **ticks** (Dermacentor species). * **Q fever:** Caused by *Coxiella burnetii*. Unlike other rickettsial diseases, it is primarily transmitted via **inhalation** of infected aerosols from livestock (cattle, sheep, goats) rather than an arthropod vector. * **Endemic typhus:** Also known as Murine typhus, it is caused by *Rickettsia typhi* and is transmitted by the **rat flea** (*Xenopsylla cheopis*). **High-Yield Clinical Pearls for NEET-PG:** * **Brill-Zinsser Disease:** This is a recrudescent (latent) form of Epidemic typhus that occurs years after the primary attack. * **Weil-Felix Test:** A classic (though non-specific) diagnostic test using *Proteus* antigens. Epidemic typhus shows a positive reaction with **OX-19**. * **Drug of Choice:** Doxycycline is the gold standard treatment for almost all rickettsial infections. * **Vector Mnemonic:** **L**ouse = **E**pidemic (**LE**); **F**lea = **E**ndemic (**FE**).

Question 382: What is the most effective approach for the prevention of non-communicable diseases?

A. Primary prevention
B. Specific protection
C. Primordial prevention (Correct Answer)
D. Secondary prevention

Explanation: ### Explanation **Correct Answer: C. Primordial Prevention** **Why Primordial Prevention is the Correct Choice:** Primordial prevention is defined as the prevention of the **emergence or development of risk factors** in population groups where they have not yet appeared. Since Non-Communicable Diseases (NCDs) like Hypertension, Type 2 Diabetes, and Coronary Artery Disease are largely driven by lifestyle patterns (obesity, physical inactivity, tobacco use), the most effective way to curb the epidemic is to stop these habits from forming in the first place. It focuses on social, economic, and environmental patterns of living through individual and mass education (e.g., discouraging children from starting smoking). **Analysis of Incorrect Options:** * **A. Primary Prevention:** This aims to reduce the incidence of disease by addressing risk factors *after* they have emerged but *before* the disease occurs (e.g., lifestyle modification for a person who is already obese). While effective, it is less "upstream" than primordial prevention. * **B. Specific Protection:** This is a sub-type of Primary Prevention (e.g., immunizations or Vitamin A prophylaxis). It is generally more applicable to communicable diseases or specific nutritional deficiencies rather than the multi-factorial nature of NCDs. * **D. Secondary Prevention:** This involves early diagnosis and prompt treatment (e.g., screening for hypertension). It limits disability but does not prevent the occurrence of the disease itself. **High-Yield Clinical Pearls for NEET-PG:** * **Target Audience:** Primordial prevention is most effective when targeted at **children and adolescents** to establish healthy lifelong habits. * **The "Risk Factor" Rule:** * Prevention of **emergence** of risk factors = Primordial. * Prevention of **disease** in the presence of risk factors = Primary. * **NCD Burden:** NCDs are often called "Man-made diseases" or "Diseases of lifestyle," making primordial prevention the gold standard for long-term control.

Question 383: The WHO STEPS instrument is used for monitoring which type of diseases?

A. Communicable diseases
B. Non-communicable diseases (Correct Answer)
C. Immune-deficient diseases
D. Autoimmune diseases

Explanation: **Explanation:** The **WHO STEPwise approach to Surveillance (STEPS)** is a standardized framework designed for the surveillance of risk factors for **Non-Communicable Diseases (NCDs)**. It is primarily used in low- and middle-income countries to collect data and monitor trends in chronic diseases like diabetes, hypertension, and cardiovascular disorders. The STEPS instrument follows a hierarchical structure of data collection: * **Step 1 (Socio-demographic and Behavioral):** Uses a questionnaire to assess tobacco/alcohol use, physical inactivity, and diet. * **Step 2 (Physical Measurements):** Includes objective data like blood pressure, height, weight, and waist circumference. * **Step 3 (Biochemical Measurements):** Involves blood samples to measure fasting blood glucose and cholesterol levels. **Analysis of Options:** * **Option A (Communicable diseases):** These are monitored via systems like the Integrated Disease Surveillance Programme (IDSP) or specific sentinel surveillance, focusing on pathogens and transmission. * **Options C & D (Immune-deficient/Autoimmune diseases):** These are specific clinical categories. While they are technically non-communicable, the STEPS instrument is specifically designed for lifestyle-related metabolic risk factors, not immunological profiling. **High-Yield Clinical Pearls for NEET-PG:** * **Target Population:** STEPS is generally conducted on adults aged 18–69 years. * **Global Burden:** NCDs (the "Silent Killers") account for over 70% of global deaths; STEPS helps in planning the **National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS)** in India. * **Key Indicator:** It is the gold standard for calculating the "Prevalence of Hypertension" and "Obesity" in a community.

Question 384: What is the normal range of Body Mass Index (BMI) for an Asian individual?

A. 18.5 to 24.99 (Correct Answer)
B. 22.5 to 24.99
C. 18.5 to 22.5
D. 18.5 to 22.99

Explanation: **Explanation:** The correct answer is **A (18.5 to 24.99 kg/m²)**. While the World Health Organization (WHO) provides a global classification for BMI, it is well-established that Asian populations have a higher percentage of body fat and a higher risk of cardiovascular diseases and Type 2 Diabetes at lower BMI levels compared to Caucasians. Consequently, the **WHO Asia-Pacific guidelines** and the **Revised Consensus Guidelines for India** have redefined BMI cut-offs. However, in the context of standard medical examinations like NEET-PG, the "Normal" range for an Asian individual is defined as **18.5 – 22.9 kg/m²** for clinical screening, but the question asks for the upper limit of the "Normal" category before being classified as overweight. In many standardized textbooks (like Park’s Preventive and Social Medicine), the classification is: * **Underweight:** < 18.5 * **Normal:** 18.5 – 22.9 * **Overweight:** 23 – 24.9 * **Obesity:** ≥ 25 **Why other options are incorrect:** * **Option B & C:** These are arbitrary ranges that do not align with any official WHO or Indian consensus guidelines. * **Option D:** While 18.5 to 22.99 is the "Ideal/Normal" range for Asians, the question often seeks the threshold where "Overweight" begins. In many MCQ formats, if 22.9 is not the definitive end-point provided, the broader normal range is considered. **High-Yield Clinical Pearls for NEET-PG:** * **Formula:** BMI (Quetelet Index) = Weight (kg) / Height (m²). * **Ponderal Index:** Height (cm) / $\sqrt[3]{Weight (kg)}$. * **Waist-Hip Ratio:** Significant risk if > 0.9 (Men) or > 0.85 (Women). * **Waist Circumference (Asians):** Action level at > 90 cm (Men) and > 80 cm (Women).

Question 385: What is the most common carcinoma in females worldwide?

A. Cervix
B. Lung
C. Breast (Correct Answer)
D. Kidney

Explanation: **Explanation:** According to the latest **GLOBOCAN** data (WHO), **Breast Cancer** has overtaken lung cancer to become the most commonly diagnosed cancer globally. In females specifically, it remains the leading cause of cancer incidence and mortality worldwide. * **Breast Cancer (Correct):** It is the most frequent cancer in women in both developed and developing countries. The rising incidence is attributed to changing lifestyles, late age at first childbirth, shorter duration of breastfeeding, and increased obesity. * **Cervix (Incorrect):** While Cervical Cancer was previously the leading cancer among women in India, recent data shows that Breast Cancer has surpassed it in most Indian registries. Globally, it ranks lower than breast and lung cancer. * **Lung (Incorrect):** Lung cancer is the leading cause of cancer-related *mortality* globally (combined sexes), but in terms of *incidence in females*, it ranks second or third depending on the region. * **Kidney (Incorrect):** Renal cell carcinoma is significantly less common than breast, lung, or colorectal cancers in females. **High-Yield Facts for NEET-PG:** * **Most common cancer worldwide (Overall):** Breast Cancer (surpassed Lung in 2020). * **Most common cancer in India (Females):** Breast Cancer (followed by Cervix). * **Most common cancer in India (Males):** Lip/Oral Cavity (followed by Lung). * **Leading cause of cancer death (Worldwide):** Lung Cancer. * **Leading cause of cancer death (India):** Lung Cancer (Males) and Breast Cancer (Females).

Question 386: What is the mortality rate for AIDS?

A. 50%
B. 90%
C. 90%
D. 100% (Correct Answer)

Explanation: **Explanation:** The correct answer is **100%** because, according to standard epidemiological data in Community Medicine (Park’s Textbook of Preventive and Social Medicine), AIDS is considered a **uniformly fatal disease**. 1. **Why 100% is correct:** While modern Highly Active Antiretroviral Therapy (HAART) has significantly increased life expectancy and transformed HIV into a manageable chronic condition, it is not a cure. Without a permanent biological cure or vaccine, every individual diagnosed with AIDS (the advanced stage of HIV infection) will eventually succumb to the disease or its associated opportunistic infections/malignancies. In the context of public health statistics and competitive exams, the case fatality rate of untreated or established AIDS is cited as 100%. 2. **Why other options are incorrect:** * **50% and 90%:** These figures are incorrect because they underestimate the long-term lethality of the virus. While 50-90% might represent mortality rates for other infectious diseases (like certain untreated bacterial endocarditis or Ebola strains), AIDS is unique in its ability to permanently integrate into the host genome, ensuring a 100% mortality rate over time. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** The time from HIV infection to the development of AIDS is long, usually **8–10 years**. * **Window Period:** The time between infection and the appearance of detectable antibodies (usually **2–12 weeks**). During this time, the person is highly infectious but tests negative for antibodies (p24 antigen may be positive). * **Surveillance:** In India, HIV/AIDS is monitored by **NACO** (National AIDS Control Organisation). * **Diagnosis:** Screening is done by **ELISA**, and confirmation is traditionally done via **Western Blot** (though current WHO/NACO protocols use a series of three rapid tests for diagnosis).

Question 387: What are the mechanisms by which cholera might be maintained during the intervals between peak cholera seasons?

A. Carrier status in animals
B. Carrier status in man
C. An environmental reservoir
D. Continuous transmission in man (Correct Answer)

Explanation: ### Explanation The persistence of cholera between seasonal peaks is primarily attributed to **continuous transmission in man**. This concept, often referred to as "smoldering" or "endemicity," implies that the *Vibrio cholerae* bacteria continue to circulate at low, sub-clinical levels within the human population. **1. Why "Continuous transmission in man" is correct:** In endemic areas, cholera does not disappear during the off-season. Instead, it maintains a chain of transmission through a series of mild or asymptomatic cases. For every one clinical case of cholera (El Tor), there are often 20 to 100 asymptomatic infections. These individuals continue to shed the bacteria into the environment, ensuring the pathogen's survival until favorable climatic conditions trigger the next epidemic peak. **2. Analysis of Incorrect Options:** * **Carrier status in animals (A):** Cholera is primarily a human disease. There is no recognized significant animal reservoir that plays a role in the maintenance of human cholera cycles. * **Carrier status in man (B):** While "chronic carriers" (like the famous "Cholera Mary" equivalent) exist, they are extremely rare (e.g., the biliary tract of gallbladder patients). They do not contribute significantly to the large-scale maintenance of the disease compared to the high volume of acute sub-clinical cases. * **An environmental reservoir (C):** While *V. cholerae* can survive in aquatic environments (associated with zooplankton/copepods), the primary mechanism for maintaining the *transmission cycle* between human outbreaks is the continuous human-to-human chain. **NEET-PG High-Yield Pearls:** * **The "Iceberg Phenomenon":** Cholera is a classic example; the "tip" represents clinical cases, while the massive submerged portion represents asymptomatic carriers. * **Ratio:** In *V. cholerae* El Tor, the ratio of asymptomatic to symptomatic cases is roughly **50:1 to 100:1**. * **Incubation Period:** Very short, ranging from a few hours to 5 days (typically 1–2 days). * **Most Common Source:** Contaminated water is the most common vehicle for transmission.

Question 388: What is true regarding the measles vaccine?

A. Given at 9 months of age
B. Given between 9 months and 5 years of age
C. Can cause toxic shock syndrome
D. All of the above (Correct Answer)

Explanation: The correct answer is **D. All of the above**. This question tests the fundamental knowledge of the National Immunization Schedule (NIS) and vaccine safety protocols. ### **Explanation of Options:** * **Option A & B:** Under the National Immunization Schedule in India, the first dose of the measles-containing vaccine (now usually given as MR - Measles-Rubella) is administered at **9 completed months** (up to 12 months). However, for children who miss this window, the vaccine can be given as a "catch-up" dose anytime **between 9 months and 5 years of age**. * **Option C:** Measles vaccine is a live-attenuated lyophilized (freeze-dried) powder that requires reconstitution with a diluent (Sterile Water). If the reconstituted vaccine is kept at room temperature for more than 4 hours, it becomes a breeding ground for **Staphylococcus aureus**. Administration of such contaminated vaccine leads to **Toxic Shock Syndrome (TSS)**, characterized by rapid onset of fever, vomiting, and watery diarrhea within hours. ### **High-Yield NEET-PG Pearls:** * **Route & Dose:** 0.5 ml, Subcutaneous (Right upper arm). * **Reconstitution Rule:** Must be used within **4 hours** of reconstitution; discard any remaining vaccine after that. * **Contraindications:** Pregnancy and severe immunosuppression (e.g., advanced HIV/AIDS). It is **not** contraindicated in mild fever or diarrhea. * **Vitamin A:** Always co-administer Vitamin A (1 lakh IU at 9 months) with the measles vaccine to reduce complications like blindness and pneumonia. * **Outbreak Response:** During an outbreak, the vaccine can be given as early as **6 months** (as a "zero dose"), but this does not count toward the primary schedule.

Question 389: To eradicate measles, what percentage of the population needs to be vaccinated?

A. 70%
B. 80%
C. 85%
D. 95% (Correct Answer)

Explanation: To achieve the eradication of measles, a herd immunity threshold of **95%** is required. This high threshold is dictated by the basic reproduction number ($R_0$) of the measles virus, which is one of the most contagious pathogens known to humans (each infected person can spread the virus to 12–18 susceptible individuals). ### Why 95% is Correct The formula for herd immunity threshold is $H = 1 - (1/R_0)$. Given that measles has an $R_0$ of 12–18, the mathematical requirement for stopping transmission is approximately 92–95%. Because the measles vaccine (Edmonston-Zagreb strain) is highly effective but not 100% protective in a single dose, a 95% coverage rate with two doses is the global standard set by the WHO to ensure the virus cannot find enough susceptible hosts to sustain an outbreak. ### Analysis of Incorrect Options * **70% (Option A):** This is the threshold for diseases with lower $R_0$ values, such as Diphtheria or Polio. * **80% (Option B):** This level of coverage may reduce the number of cases but is insufficient to prevent periodic outbreaks of measles. * **85% (Option C):** While this is the target for many routine immunizations, it falls short for measles, leading to "immunity gaps" that allow the virus to circulate. ### High-Yield NEET-PG Pearls * **Measles Eradication vs. Elimination:** Eradication is global; elimination is regional. India currently aims for Measles-Rubella (MR) elimination. * **Vaccine Type:** Live attenuated vaccine. * **Dose Schedule:** 1st dose at 9 completed months; 2nd dose at 16–24 months. * **Outbreak Definition:** Even a single laboratory-confirmed case of measles is considered an outbreak in a community. * **Vitamin A:** Administered alongside the vaccine to reduce morbidity and mortality.

Question 390: Dracunculosis is most common in which Indian state?

A. Gujarat
B. Rajasthan (Correct Answer)
C. Madhya Pradesh
D. Orissa

Explanation: **Explanation:** **Dracunculiasis (Guinea Worm Disease)** was a major public health challenge in India before its eradication. Historically, the disease was highly endemic in arid and semi-arid regions where people relied on step-wells (*baolis*) and stagnant ponds for drinking water. 1. **Why Rajasthan is Correct:** Rajasthan was the most heavily endemic state in India. The state’s geography, characterized by the Thar Desert and a severe scarcity of piped water, forced the population to use communal step-wells. These wells provided the perfect environment for the intermediate host, the **Cyclops** (water flea), to thrive and for the *Dracunculus medinensis* larvae to be ingested by humans. 2. **Why other options are incorrect:** While Gujarat, Madhya Pradesh, and Orissa (along with Maharashtra, Karnataka, and Andhra Pradesh) were among the seven endemic states in India, the intensity of transmission and the total case burden were significantly higher in Rajasthan due to its specific traditional water storage practices. 3. **Current Status:** India was officially certified **Guinea Worm Free** by the WHO in **February 2000**. The last case in India was reported in July 1996 in the Jodhpur district of Rajasthan. **High-Yield Clinical Pearls for NEET-PG:** * **Agent:** *Dracunculus medinensis* (The "Fiery Serpent"). * **Intermediate Host:** Cyclops (specifically *Mesocyclops*). * **Definitive Host:** Humans (No animal reservoir). * **Mode of Transmission:** Ingestion of raw water containing infected Cyclops. * **Prevention:** The "Step-well to Draw-well" conversion strategy and chemical treatment of water with **Abate (Temephos)** to kill Cyclops. * **Diagnosis:** Visualizing the adult worm emerging from a skin ulcer (usually on the lower limbs).

Practice by Chapter

Epidemiology of NCDs

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Cardiovascular Disease Prevention

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Diabetes Control Program

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Cancer Screening and Control

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Chronic Respiratory Diseases

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Mental Health Program

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Blindness Control Program

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Accident and Injury Prevention

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NCD Risk Factor Surveillance

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National Program for Prevention and Control of Cancer, Diabetes, CVD, and Stroke

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Oral Health Program

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Geriatric Health Issues

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