Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 141: Diseases caused by arboviruses include all except?

A. Yellow fever
B. Japanese encephalitis
C. Trench fever (Correct Answer)
D. Dengue

Explanation: **Explanation:** The term **Arbovirus** (Arthropod-borne virus) refers to a group of viruses that are transmitted to humans via the bite of infected arthropods, primarily mosquitoes and ticks. The virus must undergo biological multiplication within the vector (extrinsic incubation period) before transmission. **Why Trench Fever is the correct answer:** Trench fever is caused by ***Bartonella quintana***, which is a **gram-negative bacterium**, not a virus. While it is transmitted by an arthropod (the human body louse), it does not fit the definition of an arbovirus because the causative agent is bacterial. **Analysis of Incorrect Options:** * **Yellow Fever:** Caused by a Flavivirus and transmitted primarily by the *Aedes aegypti* mosquito. It is a classic example of an arboviral disease. * **Japanese Encephalitis (JE):** Caused by a Flavivirus and transmitted by *Culex* mosquitoes (mainly *Culex tritaeniorhynchus*). It is the leading cause of viral encephalitis in Asia. * **Dengue:** Caused by the Dengue virus (Flavivirus, serotypes 1-4) and transmitted by *Aedes aegypti*. It is the most common arboviral disease globally. **High-Yield Clinical Pearls for NEET-PG:** * **Key Arbovirus Families:** Flaviviridae (Dengue, JE, Yellow Fever, West Nile, Zika), Togaviridae (Chikungunya), and Bunyaviridae (KFD). * **KFD (Kyasanur Forest Disease):** A high-yield Indian arbovirus transmitted by **ticks** (*Haemaphysalis spinigera*). * **Louse-borne diseases (Non-arboviral):** Epidemic typhus (*Rickettsia prowazekii*), Relapsing fever (*Borrelia recurrentis*), and Trench fever (*Bartonella quintana*). * **Yellow Fever Vaccine:** 17D strain (Live attenuated); provides immunity for life (as per WHO IHR).

Question 142: An organism that multiplies and develops within a host is called:

A. Cyclopropagative (Correct Answer)
B. Cyclodevelopmental
C. Developmental
D. All of the above

Explanation: ### Explanation In Community Medicine and Parasitology, the classification of biological transmission depends on whether the parasite undergoes changes in form (development) or increases in number (multiplication) within the vector/host. **1. Why Cyclopropagative is correct:** The term **Cyclopropagative** is used when the organism undergoes **both** a change in form (developmental stages) and an increase in number (multiplication). * *Example:* Malaria parasite (*Plasmodium*) in the *Anopheles* mosquito. The parasite develops from a gametocyte to a sporozoite while multiplying significantly. **2. Analysis of Incorrect Options:** * **Cyclodevelopmental (Option B):** The organism undergoes a change in form/stage but **does not multiply**. * *Example:* Filarial parasite (*Wuchereria bancrofti*) in the *Culex* mosquito or Guinea worm in *Cyclops*. One microfilaria develops into one infective larva. * **Developmental (Option C):** This is a broader, less specific term. In the context of biological transmission, "Propagative" transmission is the counterpart where the organism multiplies but does **not** change in form (e.g., Plague bacilli in rat fleas). * **All of the above (Option D):** Incorrect because the three types of transmission are mutually exclusive based on the parasite's life cycle requirements. ### NEET-PG High-Yield Pearls: * **Propagative:** Multiplication only, no change in form (e.g., Plague, Yellow Fever virus in mosquitoes). * **Cyclodevelopmental:** Change in form only, no multiplication (e.g., Filariasis, Guinea worm). * **Cyclopropagative:** Both change in form and multiplication (e.g., Malaria). * **Mechanical Transmission:** The vector acts only as a carrier; no development or multiplication occurs (e.g., Housefly carrying Typhoid bacilli).

Question 143: Which of the following is NOT transmitted by arthropods?

A. Q fever (Correct Answer)
B. Rickettsial pox
C. Rocky mountain spotted fever
D. Relapsing fever

Explanation: **Explanation:** The correct answer is **Q fever**. While most rickettsial and related diseases are transmitted via arthropod vectors, Q fever is a notable exception. **1. Why Q Fever is the Correct Answer:** Q fever is caused by *Coxiella burnetii*. Unlike other rickettsial diseases, it is primarily a **zoonosis** transmitted to humans via **inhalation** of contaminated aerosols or dust from the birth products, feces, or urine of infected livestock (sheep, goats, cattle). It can also be transmitted through the consumption of unpasteurized milk. Although ticks can carry the organism in nature, they play a negligible role in human transmission. **2. Analysis of Incorrect Options:** * **Rickettsial pox:** Caused by *Rickettsia akari*, it is transmitted by the **mite** (*Liponyssoides sanguineus*). * **Rocky Mountain Spotted Fever (RMSF):** Caused by *Rickettsia rickettsii*, it is transmitted by **ticks** (e.g., *Dermacentor variabilis*). * **Relapsing fever:** This can be **Louse-borne** (Epidemic relapsing fever caused by *Borrelia recurrentis*) or **Tick-borne** (Endemic relapsing fever caused by *Borrelia duttoni*). **3. NEET-PG High-Yield Clinical Pearls:** * **Q Fever:** It is the most heat-resistant pathogen found in milk; hence, it is used as the indicator organism for the efficiency of **pasteurization**. * **Weil-Felix Test:** This is a classic diagnostic test for rickettsial diseases, but it is **negative** in Q fever. * **Occupational Hazard:** Q fever is common among veterinarians, abattoir workers, and farmers. * **Morphology:** *Coxiella burnetii* is an obligate intracellular organism that forms spore-like structures, allowing it to survive harsh environmental conditions.

Question 144: Which of the following is an epidemiological marker of Hepatitis B?

A. HBs Ag (Correct Answer)
B. Anti - HBs
C. Anti HBc
D. HBe Ag

Explanation: **Explanation:** **Hepatitis B Surface Antigen (HBsAg)** is the correct answer because it is the first serological marker to appear in the blood after infection (appearing even before biochemical evidence like elevated ALT). In community medicine and epidemiology, it serves as the primary **marker of infection** and is used to identify both acute cases and chronic carriers. Its presence for more than 6 months defines a chronic carrier state, making it the fundamental tool for prevalence studies. **Analysis of Incorrect Options:** * **Anti-HBs:** This is a marker of **immunity**. It appears after a successful vaccination or recovery from a natural infection. It indicates that the individual is no longer infectious and is protected against future attacks. * **Anti-HBc:** This is a marker of **exposure**. Total Anti-HBc (IgG + IgM) persists for life after natural infection. It is not produced by vaccination, making it useful to distinguish between vaccine-induced immunity and natural recovery. * **HBeAg:** This is a marker of **high infectivity** and active viral replication. While it indicates the person is highly contagious, it is not the general epidemiological marker used to screen for the presence of the disease in a population. **High-Yield Clinical Pearls for NEET-PG:** * **Window Period:** The interval when HBsAg has disappeared but Anti-HBs has not yet appeared. During this time, **IgM Anti-HBc** is the only diagnostic marker present. * **Carrier State:** Defined as HBsAg persisting in the blood for **>6 months**. * **Screening:** HBsAg is the mandatory screening test for blood donors to prevent transfusion-transmitted Hepatitis B. * **Infectivity:** The presence of **HBeAg** and **HBV-DNA** correlates with the highest risk of transmission (e.g., vertical transmission from mother to child).

Question 145: All of the following statements regarding filariasis are true EXCEPT:

A. Man serves as an intermediate host. (Correct Answer)
B. It is caused by Wuchereria bancrofti.
C. It primarily involves the lymphatic system.
D. Diethylcarbamazine (DEC) is a treatment option.

Explanation: In Lymphatic Filariasis, the classification of hosts is a high-yield concept in parasitology. By definition, a **Definitive Host** is one where the parasite reaches maturity and undergoes sexual reproduction, while an **Intermediate Host** is one where the parasite undergoes asexual development or larval stages. **Explanation of the Correct Answer:** * **Option A is FALSE (Correct Answer):** In the life cycle of *Wuchereria bancrofti*, **Man is the Definitive Host** because the adult worms live, mate, and produce microfilariae within the human lymphatic system. The **Mosquito (Culex/Aedes/Anopheles) is the Intermediate Host**, as it carries the larval stages (L1 to L3). **Analysis of Other Options:** * **Option B is True:** *Wuchereria bancrofti* is responsible for approximately 90% of lymphatic filariasis cases globally, followed by *Brugia malayi*. * **Option C is True:** The adult worms reside in the afferent lymphatic vessels and lymph nodes, leading to mechanical obstruction and inflammatory changes (lymphangitis and lymphedema). * **Option D is True:** Diethylcarbamazine (DEC) is the drug of choice. It is both microfilaricidal and partially macrofilaricidal. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** The most common vector for *W. bancrofti* in India is the **Culex quinquefasciatus** mosquito (breeds in dirty/stagnant water). * **Diagnosis:** The gold standard is the demonstration of microfilariae in a **peripheral blood smear** (collected at night, usually 10 PM – 2 AM, due to nocturnal periodicity). * **Drug of Choice:** DEC (6 mg/kg for 12 days). In the Global Programme to Eliminate Lymphatic Filariasis (GPELF), a single dose of **DEC + Albendazole** (and sometimes Ivermectin) is used for Mass Drug Administration (MDA). * **Tropical Pulmonary Eosinophilia (TPE):** A hypersensitivity reaction to filarial antigens characterized by nocturnal cough, wheezing, and high eosinophil counts.

Question 146: What is the best method of contraception for a commercial sex worker?

A. Intrauterine contraceptive device (IUCD)
B. Oral contraceptive pills (OCP)
C. Permanent sterilization
D. Barrier methods (Correct Answer)

Explanation: **Explanation:** The primary concern for a commercial sex worker (CSW) is not just pregnancy prevention, but the high occupational risk of acquiring and transmitting **Sexually Transmitted Infections (STIs)** and **HIV/AIDS**. **1. Why Barrier Methods are Correct:** Barrier methods, specifically **condoms**, are the only contraceptive method that provides **dual protection**. They act as a physical barrier that prevents the exchange of bodily fluids, thereby reducing the risk of STIs (like Syphilis, Gonorrhea, and Chlamydia) and HIV, while simultaneously providing effective contraception. In public health strategy, preventing the spread of the "pool of infection" in high-risk groups is a priority. **2. Why Other Options are Incorrect:** * **IUCD (Option A):** While highly effective for contraception, IUCDs are contraindicated in women at high risk for STIs. They can facilitate the ascent of bacteria from the lower genital tract to the upper tract, significantly increasing the risk of **Pelvic Inflammatory Disease (PID)**. * **OCPs (Option B):** These provide excellent pregnancy protection but offer **zero protection** against STIs/HIV. * **Permanent Sterilization (Option C):** Like OCPs, this is a terminal method for contraception but does nothing to mitigate the high risk of infectious diseases associated with the profession. **High-Yield Clinical Pearls for NEET-PG:** * **Dual Protection:** The concept of using a method that prevents both pregnancy and STIs. * **Vulnerable Groups:** For CSWs, the "Condom Only" or "Double Method" (Condom + another highly effective method) is often recommended. * **Nonoxynol-9:** Note that spermicides containing Nonoxynol-9 are **not** recommended for CSWs as they can cause vaginal irritation, potentially increasing the risk of HIV transmission.

Question 147: What is the incubation period of measles?

A. 14 days (Correct Answer)
B. 1 month
C. 3 months
D. 5 months

Explanation: **Explanation:** The incubation period of Measles (Rubeola) is typically **10–14 days**. Specifically, it takes approximately 10 days from exposure to the onset of fever (prodromal stage) and 14 days to the appearance of the characteristic maculopapular rash. * **Why Option A is correct:** In public health and epidemiology, the standard incubation period for Measles is cited as 7–14 days, with 14 days being the most common timeframe for the full clinical manifestation (rash). * **Why Options B, C, and D are incorrect:** These durations (1–5 months) are far too long for acute viral exanthematous fevers. Such prolonged incubation periods are characteristic of chronic infections like Hepatitis B, Hepatitis C, or certain parasitic infestations. **High-Yield Clinical Pearls for NEET-PG:** * **Infectivity Period:** Measles is highly contagious from **4 days before to 4 days after** the appearance of the rash. * **Koplik’s Spots:** These are pathognomonic and appear on the buccal mucosa opposite the lower second molars 1–2 days before the rash. * **Secondary Attack Rate (SAR):** Measles has one of the highest SARs (>90%) among susceptible household contacts. * **Isolation:** Since the virus is transmitted via respiratory droplets, respiratory isolation is required for 4 days post-rash onset. * **Vitamin A:** Supplementation is recommended for all children with acute measles to prevent complications like blindness and pneumonia.

Question 148: What amount of WHO ORS is recommended for a 1-year-old child during the first 4 hours of diarrhea?

A. 200-400 ml
B. 400-600 ml
C. 600-800 ml (Correct Answer)
D. 800-1200 ml

Explanation: ### Explanation The management of dehydration in children is a high-yield topic for NEET-PG, specifically under the WHO Integrated Management of Neonatal and Childhood Illness (IMNCI) guidelines. **1. Why Option C is Correct:** According to the WHO/IMNCI **Plan B** for the treatment of **some dehydration**, the approximate amount of ORS to be given during the first 4 hours is determined by the formula: **Weight (kg) × 75 ml**. For a 1-year-old child, the standard estimated weight used in WHO charts is **10 kg**. * Calculation: 10 kg × 75 ml = **750 ml**. * The range provided in the WHO guidelines for the age group of 4 months up to 12 months (under 10 kg) is 400–700 ml, while for **12 months up to 2 years (10–12 kg)**, it is **700–900 ml**. Option C (600–800 ml) most closely aligns with the requirement for a child who has just reached 1 year of age. **2. Why Other Options are Incorrect:** * **Option A (200-400 ml):** This volume is insufficient for a 1-year-old and is typically recommended for infants aged 4 months or younger (<6 kg). * **Option B (400-600 ml):** This range is appropriate for infants aged 4 months to 11 months (6 to <10 kg). * **Option D (800-1200 ml):** This volume is excessive for a 1-year-old and is generally reserved for children aged 2 to 5 years (12–19 kg). **3. Clinical Pearls for NEET-PG:** * **Plan A:** No dehydration (Home management). * **Plan B:** Some dehydration (ORS: 75 ml/kg over 4 hours). * **Plan C:** Severe dehydration (IV Fluids: Ringer Lactate is the fluid of choice). * **Zinc Supplementation:** 20 mg/day for 14 days (10 mg/day for infants <6 months) to reduce the duration and recurrence of diarrhea. * **New WHO ORS:** It is **hypoosmolar** (Total osmolarity: 245 mOsm/L) to reduce stool output and vomiting.

Question 149: Which of the following viruses exhibits mutation?

A. Poliovirus
B. Influenza virus (Correct Answer)
C. Mumps virus
D. Measles virus

Explanation: **Explanation:** The correct answer is **Influenza virus**. The hallmark of the Influenza virus is its extreme genetic instability, which occurs through two primary mechanisms: **Antigenic Drift** and **Antigenic Shift**. 1. **Antigenic Drift:** These are point mutations in the genes coding for Hemagglutinin (HA) and Neuraminidase (NA) surface proteins. This occurs in both Influenza A and B, leading to seasonal epidemics and necessitating the annual update of the flu vaccine. 2. **Antigenic Shift:** This is a major genetic change resulting from the **reassortment** of segmented RNA genomes when two different strains infect the same cell. This only occurs in **Influenza A** and leads to global pandemics. **Why other options are incorrect:** * **Poliovirus, Mumps, and Measles viruses** are characterized by **antigenic stability**. While they are RNA viruses, they do not undergo significant mutations that change their immunological profile. This stability is the reason why a single infection or a standard course of vaccination provides lifelong immunity, unlike Influenza. **High-Yield Clinical Pearls for NEET-PG:** * **Segmented Genome:** Influenza has 8 RNA segments (Type A & B) or 7 segments (Type C). Segmented genomes are a prerequisite for Antigenic Shift. * **Pandemic Strains:** Antigenic shift is responsible for major pandemics (e.g., H1N1 Spanish Flu, H5N1 Avian Flu). * **Vaccine Composition:** The WHO recommends the composition of the "Annual Influenza Vaccine" based on the circulating strains identified through global surveillance. * **Measles/Mumps/Rubella:** These are "monotypic" viruses (only one serotype exists), making them ideal candidates for eradication via vaccination.

Question 150: All of the following are true about Japanese encephalitis except?

A. Man to man transmission is not reported.
B. Culex mosquito is the vector.
C. 90%-100% mortality rate. (Correct Answer)
D. There is no rash or local lesion.

Explanation: Japanese Encephalitis (JE) is a leading cause of viral encephalitis in Asia, caused by a Group B Arbovirus (Flavivirus). **Why Option C is the correct answer (The "Except"):** The mortality rate for Japanese Encephalitis is significantly lower than 90-100%. In clinical cases, the Case Fatality Rate (CFR) typically ranges from **20% to 30%**. While the mortality is lower than stated in the option, it is important to note that among survivors, approximately 30%–50% suffer from serious permanent neuropsychiatric sequelae. **Analysis of Incorrect Options:** * **Option A (Man to man transmission):** This is a true statement. Humans are **"Dead-end hosts"** because the level of viremia in humans is insufficient to infect a feeding mosquito. There is no direct person-to-person transmission. * **Option B (Culex mosquito):** This is true. The primary vectors are mosquitoes of the **Culex vishnui group** (*C. tritaeniorhynchus, C. vishnui, C. pseudovishnui*). They are "exophilic" (outdoor) biters and breed primarily in irrigated rice fields. * **Option D (No rash/local lesion):** This is true. Unlike other viral fevers (like Dengue), JE typically presents with sudden onset high fever, convulsions, and altered sensorium without a characteristic rash or primary skin lesion at the site of the bite. **High-Yield NEET-PG Pearls:** * **Reservoir/Amplifier Host:** Pigs are the most important "Amplifier hosts" (they develop high viremia without getting sick). * **Incidental Host:** Man and Horse. * **Sentinel Animals:** Pigs are used for surveillance to predict outbreaks. * **Vaccination:** The SA-14-14-2 (Live attenuated) vaccine is commonly used in the Universal Immunization Programme (UIP) in endemic districts of India. * **Ratio:** The ratio of overt disease to inapparent infection ranges from 1:300 to 1:1000.

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