Non-Communicable Diseases Practice Questions

Q: The time required for the development of a parasite from the gametocyte to the sporozoite stage in a mosquito is called as:

Extrinsic incubation period. ### Explanation **Correct Answer: A. Extrinsic incubation period** The **Extrinsic Incubation Period (EIP)** is the time interval required for a pathogen to develop or multiply within an arthropod vector (like a mosquito) before it becomes infective to a vertebrate host. In the context of Malaria, this represents the duration from the ingestion of **gametocytes** by the mosquito to the appearance of **sporozoites** in its salivary glands. This period is highly temperature-dependent; for *Plasmodium vivax*, it is approximately 8–10 days at 25°C. **Analysis of Incorrect Options:** * **B. Intrinsic incubation period:** This is the time interval between the entry of the pathogen into the **human host** and the onset of the first clinical sign or symptom. * **C. Generation time:** This refers to the interval between the receipt of infection by a host and the maximum infectivity of that host. In malaria, it is the time from the entry of sporozoites into a human until the peak production of gametocytes. * **D. Median incubation period:** This is a statistical measure representing the time required for 50% of an exposed population to develop the disease. **High-Yield Facts for NEET-PG:** * **Serial Interval:** The time gap between the onset of the primary case and the onset of the secondary case in a transmission chain. * **Pre-patent Period:** The time between the entry of the parasite and its first demonstration in the blood or excreta (e.g., 8 days for *P. falciparum*). * **Environmental Impact:** If the extrinsic incubation period exceeds the lifespan of the mosquito, transmission of the disease cannot occur. This is a key principle in vector control strategies.

Q: The DPT vaccine is administered via which route?

Intramuscular. **Explanation:** The **DPT (Diphtheria, Pertussis, and Tetanus)** vaccine is a combination vaccine administered via the **Intramuscular (IM)** route. In infants, the preferred site is the **anterolateral aspect of the mid-thigh**, as this area has the largest muscle mass (vastus lateralis) and avoids potential injury to the sciatic nerve. **Why Intramuscular?** DPT contains **adjuvants** (like aluminum salts) designed to enhance the immune response. These adjuvants are highly irritating to the skin and subcutaneous tissues. Injecting deep into the muscle ensures slow absorption and minimizes local reactions. **Analysis of Incorrect Options:** * **Subcutaneous:** This route is avoided for DPT because the adjuvants can cause **sterile abscesses**, localized tissue necrosis, and severe irritation if deposited in the fatty layer. (Note: Measles and Yellow Fever vaccines are typically subcutaneous). * **Intradermal:** This route is used for vaccines requiring a slow release and specific immune cell interaction, such as **BCG** or the **Rabies** vaccine (IDRV). DPT would cause significant skin damage if given this way. * **Intravenous:** Vaccines are never administered intravenously as they need to be processed by local immune cells and can cause systemic anaphylaxis if injected directly into the bloodstream. **High-Yield Clinical Pearls for NEET-PG:** * **Site:** Anterolateral thigh (Infants); Deltoid (Older children/Adults). * **Angle:** 90 degrees. * **Storage:** DPT is **heat-stable but freeze-sensitive**. It must be stored at +2°C to +8°C. If frozen, it loses potency (perform the **Shake Test** to check for damage). * **Pentavalent Vaccine:** In the National Immunization Schedule, DPT is now part of the Pentavalent vaccine (DPT + Hep B + Hib), also given IM.

Q: In which year was the Rubella virus first isolated?

1962. **Explanation:** The correct answer is **1962**. While Rubella (German Measles) was clinically described as a distinct disease as early as the 18th century, the virus itself remained elusive for decades. In 1962, two independent groups of researchers—**Parkman and Wegman** at the Walter Reed Army Institute of Research, and **Weller and Neva** at Harvard—successfully isolated the Rubella virus using tissue culture techniques. This breakthrough was pivotal as it paved the way for the development of the first Rubella vaccines in the late 1960s. **Analysis of Incorrect Options:** * **1862 (Option A):** This predates the "Golden Age of Microbiology." At this time, the germ theory was still being established, and viruses (which are much smaller than bacteria) could not yet be isolated. * **1912 (Option B):** While the viral etiology of Rubella was suspected in the early 20th century, the technology for viral cell culture (necessary for isolation) was not yet sufficiently advanced. * **1932 (Option C):** This was around the time researchers were beginning to differentiate viral exanthems, but the definitive isolation of the Rubella virus had not yet occurred. **NEET-PG High-Yield Pearls:** * **Gregg’s Phenomenon (1941):** Norman Gregg, an Australian ophthalmologist, first linked maternal Rubella infection to congenital cataracts, establishing the concept of **Congenital Rubella Syndrome (CRS)**. * **Virus Family:** Rubella belongs to the *Togaviridae* family (Genus: *Rubivirus*). * **Incubation Period:** 14–21 days (Average 18 days). * **Infectivity:** Most infectious from 7 days before to 7 days after the onset of the rash. * **Vaccine:** It is a **Live Attenuated Vaccine** (RA 27/3 strain is most commonly used). It is contraindicated in pregnancy.

Q: What is the usual incubation period of pertussis?

7-14 days. **Explanation:** **1. Why Option A is Correct:** Pertussis (Whooping Cough), caused by the bacterium *Bordetella pertussis*, typically has an incubation period of **7 to 14 days** (with an upper limit of 21 days). This is the time required for the bacteria to colonize the ciliated epithelium of the respiratory tract and produce toxins (like pertussis toxin) that trigger the initial catarrhal symptoms. **2. Why Other Options are Incorrect:** * **Option B (3-5 days):** This is too short for Pertussis but is characteristic of infections like **Diphtheria** or **Meningococcal meningitis**. * **Option C (21-25 days):** This is longer than the typical range. While the incubation period can occasionally extend to 21 days, it rarely exceeds it. This range is more typical for **Mumps** (14–21 days) or **Rubella**. * **Option D (Less than 3 days):** This very short incubation period is seen in **Influenza**, **Cholera**, or **Staphylococcal food poisoning**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Infectivity:** Pertussis is most infectious during the **Catarrhal stage** (the first 1-2 weeks). * **Drug of Choice:** **Erythromycin** (or other Macrolides like Azithromycin) is the treatment of choice. It reduces communicability but has limited impact on clinical symptoms if started late. * **Vaccination:** The vaccine is part of the National Immunization Schedule (Pentavalent/DPT). Note that the immunity (both natural and vaccine-induced) is **not lifelong**. * **Secondary Attack Rate (SAR):** It is very high, approximately **90%** in susceptible household contacts.

Q: Apart from dengue hemorrhagic fever, Aedes aegypti is a vector for the transmission of which disease?

Yellow fever. ### Explanation **Correct Answer: D. Yellow fever** **1. Why Yellow Fever is Correct:** *Aedes aegypti* is a highly efficient urban vector known for its "nervous biting" habit (biting multiple people to complete one blood meal). While it is the primary vector for **Dengue**, it is also the principal vector for **Yellow Fever**, **Chikungunya**, and **Zika virus**. In the context of Yellow Fever, *Aedes aegypti* facilitates the "Urban Cycle" of transmission between humans, whereas *Haemagogus* species are involved in the "Sylvatic (Jungle) Cycle." **2. Analysis of Incorrect Options:** * **A. Filaria:** In India, the primary vector for Lymphatic Filariasis (*Wuchereria bancrofti*) is the **Culex quinquefasciatus** mosquito, which breeds in dirty, stagnant water. * **B. Japanese Encephalitis (JE):** This is transmitted primarily by **Culex tritaeniorhynchus** and *Culex vishnui* group mosquitoes. They typically breed in irrigated rice fields. * **C. Kyasanur Forest Disease (KFD):** This is a viral hemorrhagic fever transmitted by **Hard Ticks** (*Haemaphysalis spinigera*), not mosquitoes. It is endemic to specific regions in Karnataka, India. **3. NEET-PG High-Yield Pearls:** * **Aedes aegypti Characteristics:** Known as the "Tiger Mosquito" (due to white stripes), it is a **daytime biter**, breeds in **artificial collections of clean water** (coolers, tires, flower pots), and has a flight range of usually less than 100 meters. * **Yellow Fever in India:** Although the vector (*Aedes aegypti*) is abundant in India, Yellow Fever is **not present** in India. This is a classic "vulnerable but not receptive" scenario. * **The "Aedes" Rule:** Remember the triad: **Dengue, Chikungunya, and Zika** are all transmitted by *Aedes*.

Q: In a study, a new treatment resulted in 36 deaths or treatment failures out of a sample of 120. With an alternative treatment, 26 treatment failures were reported from a sample size of 130. How many patients should be treated with the first treatment to avert one death?

10. ### Explanation The question asks for the number of patients needed to be treated with the first treatment to avert one death, which is the definition of **Number Needed to Treat (NNT)**. **1. Calculation of the Correct Answer (B):** * **Event Rate in Group 1 (EER):** 36/120 = 0.3 (30%) * **Event Rate in Group 2 (CER):** 26/130 = 0.2 (20%) * **Absolute Risk Reduction (ARR):** This is the arithmetic difference between the two event rates. * ARR = |EER – CER| = |0.3 – 0.2| = **0.1** * **Number Needed to Treat (NNT):** This is the inverse of ARR. * NNT = 1 / ARR = 1 / 0.1 = **10** * Therefore, 10 patients must be treated with the first treatment to prevent one additional death compared to the second treatment. **2. Why other options are incorrect:** * **Option A (100):** This is a common calculation error where the decimal point is misplaced (1/0.01 instead of 1/0.1). * **Option C (250):** This value does not correlate with the mathematical relationship between the provided sample sizes and outcomes. * **Option D (160):** This might result from incorrectly adding the total number of failures (36+26) or misapplying the formula. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **NNT Formula:** $1 / \text{Absolute Risk Reduction (ARR)}$. * **Interpretation:** The lower the NNT, the more effective the treatment. An NNT of 1 means every single patient treated benefits. * **Number Needed to Harm (NNH):** Calculated similarly ($1 / \text{Absolute Risk Increase}$), it indicates how many patients must be exposed to a risk factor to cause one adverse event. * **Relative Risk Reduction (RRR):** Unlike ARR, RRR does not account for the baseline risk and can often make a treatment's effect look more impressive than it is.

Q: What is the vector responsible for the transmission of Kyasanur Forest Disease (KFD)?

Hard tick. **Explanation:** **Kyasanur Forest Disease (KFD)**, commonly known as "Monkey Fever," is a viral hemorrhagic fever endemic to South India (primarily Karnataka). It is caused by the KFD virus, a member of the *Flaviviridae* family. 1. **Why Option B is Correct:** The primary vector for KFD is the **Hard tick**, specifically species belonging to the genus ***Haemaphysalis*** (most notably *Haemaphysalis spinigera*). Ticks act as both the vector and the reservoir for the virus. Humans usually contract the disease through a tick bite or via contact with an infected animal, most commonly monkeys (Langurs and Bonnet macaques), which act as amplifier hosts. 2. **Why Other Options are Incorrect:** * **A. Soft tick:** These are vectors for diseases like Tick-borne Relapsing Fever (TBRF), but not KFD. * **C. Louse:** Body lice are responsible for transmitting Epidemic Typhus, Relapsing Fever, and Trench Fever. * **D. Bug:** Reduviid bugs (Triatomine) transmit Chagas disease, while Bed bugs are not known vectors for major systemic human diseases. **High-Yield Clinical Pearls for NEET-PG:** * **Reservoirs:** Wild rodents and monkeys. Monkeys are "sentinel" animals; their death in a forest often signals a KFD outbreak. * **Seasonality:** Most cases occur during the dry season (January to June) when human activity in forests increases. * **Clinical Presentation:** Characterized by sudden onset high fever, severe headache, myalgia, and hemorrhagic manifestations. A "biphasic" fever pattern is sometimes seen. * **Prevention:** A **formalin-inactivated vaccine** is available and used in endemic areas for individuals aged 7–65 years.

Q: Which formula is denoted by (Weight = Height - 100)?

Broca index. **Explanation:** The **Broca Index** is a simple, historical method used to estimate a person’s **Ideal Body Weight (IBW)** in kilograms based on their height in centimeters. The formula is: **Ideal Weight (kg) = Height (cm) – 100** While easy to calculate bedside, it is less precise than modern methods because it does not account for age, gender, or frame size. However, it remains a high-yield concept in Community Medicine for rapid nutritional assessment. **Analysis of Incorrect Options:** * **A. Corpulence Index:** Also known as the Ponderal Index or Rohrer's Index, it is calculated as $Weight (kg) / Height (m)^3$. It is primarily used in pediatrics to assess fetal growth and neonates. * **C. Lorentz’s Formula:** This is a more refined version of the Broca Index that accounts for gender. * *Males:* $Height – 100 – [(Height – 150) / 4]$ * *Females:* $Height – 100 – [(Height – 150) / 2]$ * **D. Quetelet’s Index:** This is the formal name for the **Body Mass Index (BMI)**, calculated as $Weight (kg) / Height (m)^2$. It is the current gold standard for classifying overweight and obesity. **High-Yield Clinical Pearls for NEET-PG:** * **BMI Classifications (WHO):** Underweight ( 0.9 in men** or **>0.85 in women**.

Question 1

The time required for the development of a parasite from the gametocyte to the sporozoite stage in a mosquito is called as:

Accepted Answer

Extrinsic incubation period

Answer

Intrinsic incubation period

Answer

Generation time

Answer

Median incubation period

Question 2

The DPT vaccine is administered via which route?

Accepted Answer

Intramuscular

Answer

Subcutaneous

Answer

Intradermal

Answer

Intravenous

Question 3

In which year was the Rubella virus first isolated?

Accepted Answer

1962

Answer

1862

Answer

1912

Answer

1932

Question 4

What is the usual incubation period of pertussis?

Accepted Answer

7-14 days

Answer

3-5 days

Answer

21-25 days

Answer

Less than 3 days

Question 5

Apart from dengue hemorrhagic fever, Aedes aegypti is a vector for the transmission of which disease?

Accepted Answer

Yellow fever

Answer

Filaria

Answer

Japanese encephalitis

Answer

Kyasanur forest disease

Question 6

All of the following are true about malaria, except?

Accepted Answer

Infant parasite rate is a poor indicator of malaria occurrence in a community.

Answer

The vector for transmission is the Anopheles mosquito.

Answer

Newborns are resistant to P. falciparum infection.

Answer

Anopheles culicifacies is common in rural areas.

Question 7

In a study, a new treatment resulted in 36 deaths or treatment failures out of a sample of 120. With an alternative treatment, 26 treatment failures were reported from a sample size of 130. How many patients should be treated with the first treatment to avert one death?

Accepted Answer

10

Answer

100

Answer

250

Answer

160

Question 8

Which of the following statements about Pulse Polio immunization is false?

Accepted Answer

AFP surveillance is performed in all children less than 5 years of age.

Answer

Mop-up immunization is conducted in restricted geographical areas.

Answer

It is carried out in all children less than 5 years of age.

Answer

Mopping-up is done in areas where wild poliovirus is found.

Question 9

What is the vector responsible for the transmission of Kyasanur Forest Disease (KFD)?

Accepted Answer

Hard tick

Answer

Soft tick

Answer

Louse

Answer

Bug

Question 10

Which formula is denoted by (Weight = Height - 100)?

Accepted Answer

Broca index

Answer

Corpulence index

Answer

Lorentz's formula

Answer

Quetelet's index

Non-Communicable Diseases — MCQs

Non-Communicable Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?