Non-Communicable Diseases Practice Questions

Q: What is the post-exposure rabies vaccination schedule for a patient who has already been immunized?

0, 3. **Explanation:** The correct answer is **A (0, 3)**. This follows the WHO and National Guidelines for Rabies Prophylaxis regarding **re-exposure** in previously immunized individuals. **1. Why Option A is Correct:** When a person has documented evidence of a complete pre-exposure or post-exposure vaccination course (using modern Cell Culture Vaccines), they possess "immunological memory." Upon re-exposure, a rapid "booster" effect is required to elevate antibody titers. The recommended schedule is **two doses** of the vaccine, administered intramuscularly (or intradermally) on **Days 0 and 3**. Crucially, Rabies Immunoglobulin (RIG) is **not** required for these patients, even for Category III bites. **2. Why Other Options are Incorrect:** * **Option B (0, 3, 14):** This is not a standard recognized schedule for rabies. * **Option C (0, 7, 28):** This is the standard **Pre-exposure Prophylaxis (PrEP)** schedule for high-risk individuals (e.g., veterinarians, lab workers). * **Option D (8, 4, 0, 1, 1):** This refers to the **Thai Red Cross (Intradermal) Schedule** (2-2-2-0-2), but the numbers provided are jumbled and do not represent a standard post-exposure regimen. **High-Yield Clinical Pearls for NEET-PG:** * **Definition of "Previously Immunized":** A person who has received a full course of PEP or PrEP with Cell Culture Vaccine (CCV) or Purified Duck Embryo Vaccine (PDEV). * **RIG Rule:** RIG is contraindicated in previously immunized individuals as it may interfere with the secondary immune response. * **Standard PEP (Unvaccinated):** The Essen schedule (IM) is **0, 3, 7, 14, 28**. * **Site of Injection:** Always the **deltoid** in adults and the **anterolateral thigh** in children. **Never** in the gluteal region (due to lower neutralizing antibody titers).

Q: Which disease requires a vaccination certificate for international travel?

Yellow fever. **Explanation:** The correct answer is **Yellow Fever**. Under the **International Health Regulations (IHR 2005)**, Yellow Fever is currently the only disease for which an International Certificate of Vaccination or Prophylaxis (ICVP) is legally required for travel between endemic and non-endemic zones. **Why Yellow Fever is correct:** Yellow Fever is a viral hemorrhagic fever transmitted by the *Aedes aegypti* mosquito. To prevent the "re-introduction" of the virus into countries where the vector is present but the disease is not (like India), travelers arriving from endemic zones (Sub-Saharan Africa and South America) must provide a valid vaccination certificate. The vaccine used is the **17D strain**, and the certificate becomes valid **10 days** after vaccination, lasting for the **lifetime** of the individual. **Why the other options are incorrect:** * **Cholera:** While previously required, the WHO removed Cholera from the list of mandatory vaccinations for international travel because the parenteral vaccine provides poor protection and does not prevent asymptomatic carriage. * **Hepatitis & Tetanus:** These are recommended vaccinations for personal protection based on the traveler's destination and risk profile, but they are not legally mandated by international law for border crossing. **High-Yield Clinical Pearls for NEET-PG:** * **Validity:** A Yellow Fever certificate is valid for life (as per 2016 WHO amendment). * **Quarantine:** If a traveler from an endemic zone lacks a valid certificate, they are kept in a mosquito-proof isolation ward for **6 days** (the incubation period of the disease). * **Polio:** Note that some countries (including India) may require Polio vaccination (OPV/IPV) for travelers coming from specific polio-endemic countries, but Yellow Fever remains the primary global requirement under IHR.

Q: All of the following are modes of transmission of leprosy except?

Blood transfusion. **Explanation:** Leprosy, caused by *Mycobacterium leprae*, is primarily a chronic infectious disease of the skin and peripheral nerves. Understanding its transmission is crucial for NEET-PG. **Why Blood Transfusion is the Correct Answer:** Unlike many other bacterial infections, **blood transfusion** is not a recognized mode of transmission for leprosy. *M. leprae* is an obligate intracellular pathogen that resides primarily within macrophages and Schwann cells. It does not survive well or circulate in the free plasma in concentrations sufficient to cause infection via transfusion. **Analysis of Incorrect Options:** * **Droplet Infection (Option D):** This is the **most common** and primary route of transmission. Bacilli are shed in large numbers from the nasal mucosa of untreated lepromatous patients and enter the susceptible host through the upper respiratory tract. * **Transplacental Spread (Option C):** Vertical transmission from an infected mother to the fetus across the placenta has been documented, though it is relatively rare. * **Breast Milk (Option A):** *M. leprae* has been detected in the breast milk of lactating mothers with lepromatous leprosy, making it a possible, albeit less common, route of transmission. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** Average 3–5 years (the longest among bacterial infections). * **Portal of Entry:** Respiratory tract (most common) and broken skin. * **Infectivity:** Patients become non-infectious within days of starting Multidrug Therapy (MDT). * **Classification:** Ridley-Jopling (Immunological) vs. WHO (Operational: Paucibacillary vs. Multibacillary). * **First Sign:** Usually a pale (hypopigmented) or reddish patch on the skin with loss of sensation.

Q: Which indicator best represents the vector's burden in human malaria transmission?

Man biting rate. ### Explanation **Correct Option: A. Man biting rate** The **Man Biting Rate (MBR)** is the most direct measure of the **vector's burden** in the transmission cycle. It is defined as the average number of bites received by a single person from a specific vector species per unit of time (usually per day). Since malaria transmission depends entirely on the frequency of contact between the mosquito and the human host, MBR is the primary indicator of the intensity of the vector's activity and the risk of exposure. **Analysis of Incorrect Options:** * **B. Inoculation Rate:** This measures the number of **infective** bites per person per unit of time. While it indicates transmission risk, it is a subset of the biting rate (only counting mosquitoes with sporozoites) and represents the "force of infection" rather than the overall vector burden. * **C. Slide Positive Rate (SPR):** This is a **parasitological indicator** derived from human surveillance (number of positive slides per 100 slides examined). It reflects the prevalence of the disease in the human population, not the vector's burden. * **D. Human Blood Index (HBI):** This measures the proportion of blood meals taken by a mosquito population from human hosts versus animals. It indicates the **host preference (anthropophily)** of the vector but does not quantify the frequency of biting or the total burden. **High-Yield Pearls for NEET-PG:** * **Annual Parasite Incidence (API):** The most sensitive index for measuring malaria burden in a community (used for planning under NCVBDC). * **Annual Blood Examination Rate (ABER):** Measures the efficiency of the surveillance system (Target: >10%). * **Entomological Inoculation Rate (EIR):** The best measure of the "force of infection" in an area (MBR × Sporozoite Rate). * **Infant Parasite Rate:** The best indicator of **recent/ongoing transmission** in a locality.

Question 1

What is the post-exposure rabies vaccination schedule for a patient who has already been immunized?

Accepted Answer

0, 3

Answer

0, 3, 14

Answer

0, 7, 28

Answer

8, 4, 0, 1, 1

Question 2

Which disease requires a vaccination certificate for international travel?

Accepted Answer

Yellow fever

Answer

Cholera

Answer

Hepatitis

Answer

Tetanus

Question 3

All of the following are modes of transmission of leprosy except?

Accepted Answer

Blood transfusion

Answer

Breast milk

Answer

Transplacental spread

Answer

Droplet infection

Question 4

Which indicator best represents the vector's burden in human malaria transmission?

Accepted Answer

Man biting rate

Answer

Inoculation rate

Answer

Slide positive rate

Answer

Human blood index

Question 5

What is the mechanism of action of cholera toxin?

Accepted Answer

Both binding to the ganglioside GM1 receptor and stimulation of adenyl cyclase activity

Answer

Ganglioside GM1 receptor

Answer

Stimulation of adenyl cyclase activity

Answer

Exotoxin action leading to disruption of cell function

Non-Communicable Diseases — MCQs

Non-Communicable Diseases — MCQs

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