Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 251: A patient from Bihar is admitted with splenomegaly and clinical features suggestive of leishmaniasis. What is the vector responsible for transmitting this disease?

A. Phlebotomus (Correct Answer)
B. Rat flea
C. Black fly
D. Chrysops fly

Explanation: ***Phlebotomus*** - **Phlebotomus** (sandfly), specifically ***Phlebotomus argentipes*** in India, is the principal vector for transmitting **Leishmania donovani** parasites causing **visceral leishmaniasis (kala-azar)**. - Bihar is a highly endemic region for kala-azar in India. - The sandfly transmits the parasite when it takes a blood meal from an infected host and then bites an uninfected individual. *Rat flea* - The **rat flea** (**Xenopsylla cheopis**) is the primary vector for diseases like **bubonic plague** and **murine typhus**, not leishmaniasis. - It transmits bacteria such as *Yersinia pestis* and *Rickettsia typhi*. *Black fly* - **Black flies** (**Simulium species**) are vectors for **onchocerciasis** (river blindness), caused by the parasitic worm *Onchocerca volvulus*. - They transmit the microfilariae when biting humans. *Chrysops fly* - The **Chrysops fly** (deer fly or mango fly) is the vector for **Loa loa filariasis** (African eye worm). - It transmits *Loa loa* eyeworm larvae when it bites humans.

Question 252: Abdominal TB can occur through all of the following EXCEPT

A. Direct spread from mesenteric lymph nodes
B. Feco - oral route
C. Direct contact with infected animal (Correct Answer)
D. Hematogenous spread

Explanation: ***Direct contact with infected animal*** - While animal products like **unpasteurized milk** can transmit *Mycobacterium bovis* to humans, direct contact with an infected animal is not a primary mode of transmission for **abdominal TB**. - **Abdominal TB** is usually caused by *Mycobacterium tuberculosis* which is primarily a human pathogen, not typically transmitted through direct contact with animals. *Direct spread from mesenteric lymph nodes* - **Mesenteric lymph nodes** are often involved in abdominal TB, and the infection can directly spread from these nodes to adjacent abdominal organs. - This is a common mechanism for localized propagation within the abdominal cavity. *Feco - oral route* - The **ingestion of contaminated food or milk** (from infected cattle) containing *Mycobacterium bovis* or swallowing of **infected sputum** (from pulmonary TB) containing *Mycobacterium tuberculosis* are common ways the bacteria can reach the gastrointestinal tract. - This leads to primary intestinal infection or reactivation of previously ingested bacteria. *Hematogenous spread* - **Hematogenous dissemination** from a primary pulmonary or other mycobacterial focus is a significant mode of transmission for abdominal TB. - Bacteria can travel through the bloodstream and seed distant abdominal organs, including the **peritoneum**, **intestines**, or **mesenteric lymph nodes**.

Question 253: Which of the following indicators can help determine whether the health system is effective at identifying leprosy cases early in the community?

A. Proportion of newly diagnosed patients with grade 2 disability (Correct Answer)
B. Annual new case detection rate per lac
C. Treatment initiation rate
D. Treatment completion rate

Explanation: ***Proportion of newly diagnosed patients with grade 2 disability*** - A **high proportion of newly diagnosed patients with grade 2 disability** indicates late detection of leprosy, suggesting shortcomings in the health system's ability to identify cases early. - Grade 2 disability in leprosy signifies **visible and irreversible damage** to eyes, hands, or feet, which would likely have been prevented with earlier diagnosis and treatment. *Annual new case detection rate per lac* - The **annual new case detection rate** reflects the number of new cases identified but does not directly indicate the timeliness of detection or the effectiveness of early case-finding efforts. - A high new case detection rate could be due to intensive active case-finding campaigns, but without knowing the disability status at diagnosis, it doesn't confirm early detection by the routine health system. *Treatment initiation rate* - The **treatment initiation rate** measures the percentage of diagnosed patients who start treatment, which is crucial for disease control but does not reflect how early cases are identified. - A high initiation rate indicates good patient adherence to treatment protocols after diagnosis, but not the efficiency of the health system in finding cases before they develop advanced disability. *Treatment completion rate* - The **treatment completion rate** indicates the effectiveness of the treatment program and patient adherence, which is vital for preventing drug resistance and relapse. - This metric does not provide information about when the diagnosis was made in the disease progression or the health system's ability to identify cases early.

Question 254: Which of the following is the true statement regarding measures to prevent typhoid transmission in the community?

A. Typhoid vaccine administration is the best method of preventing transmission.
B. Person-to-person transmission is the primary mode of spread.
C. Drug resistance in typhoid is not as big a problem as in TB.
D. Hygiene practice and clean sanitation control are more important than the typhoid vaccine. (Correct Answer)

Explanation: ***Hygiene practice and clean sanitation control is more important than the typhoid vaccine.*** - **Improved sanitation**, safe water supplies, and adequate hygiene practices are fundamental in controlling the spread of **typhoid fever**, as the disease is primarily transmitted through the **oral-fecal route**. - While vaccines are an important tool, they offer only partial protection and must be combined with **robust public health infrastructure** and **sanitation measures** for effective prevention. *Typhoid vaccine administration is the best method of preventing transmission.* - Typhoid vaccines offer protection, but their effectiveness is not 100%, and they typically require **booster doses** - **Vaccination campaigns** are most effective when implemented alongside improvements in **water and sanitation infrastructure**, as vaccines alone cannot fully prevent transmission in areas with poor hygiene. *Person-to-person transmission is the primary mode of spread.* - While person-to-person transmission can occur, especially in settings with poor hygiene, the primary mode of spread for typhoid is through the **ingestion of food or water contaminated** with the feces of an infected person or carrier. - This emphasizes the crucial role of **water and food safety** rather than just focusing on direct person-to-person contact. *Drug resistance in typhoid is not as big a problem as in TB.* - **Antimicrobial resistance (AMR)** in typhoid fever, particularly to fluoroquinolones and extended-spectrum beta-lactamase (ESBL) producing strains, is a **significant and growing global health concern**, complicating treatment. - While TB also faces serious drug resistance issues, the escalating problem of **extensively drug-resistant (XDR)** and **multi-drug resistant (MDR)** typhoid strains makes it a substantial threat, impacting treatment options and increasing morbidity and mortality.

Question 255: As per the National Tuberculosis Elimination Program (NTEP), HIV TB prevalence of what percentage would deem a district a high priority district?

A. >15 %
B. >20 %
C. >10 % (Correct Answer)
D. >12 %

Explanation: ***>10%*** - As per the **National Tuberculosis Elimination Program (NTEP)** guidelines, a district is categorized as a **high-priority district** for HIV-TB co-infection if the prevalence of HIV among TB patients is **greater than 10%**. - This threshold helps in identifying regions that require enhanced focus and resources for **integrated HIV and TB care** and prevention strategies. - This is the specific cut-off defined by NTEP for prioritizing districts for targeted interventions. *>15%* - While 15% would also indicate a high prevalence, the specific threshold set by NTEP for deeming a district high priority is **>10%**, not >15%. - Districts with prevalence between 10% and 15% would already be classified as high priority at the >10% threshold. *>20%* - A prevalence of >20% would certainly indicate a severe problem, but the **NTEP's definition** for a high-priority district is specifically **>10%**. - Using a higher threshold like 20% would delay interventions in districts that already face significant challenges with HIV-TB co-infection. *>12%* - The NTEP guidelines use a specific cut-off of **>10%** for defining high-priority districts for HIV-TB co-infection. - While 12% exceeds the 10% threshold, it is not the defining threshold mentioned in the official guidelines for this classification.

Question 256: In all the following places, hand rub can be used according to standard hand hygiene protocol, except...

A. If the hands are visibly soiled (Correct Answer)
B. While moving from a contaminated site to a clean site during patient care
C. During direct patient contact
D. Before donning gloves

Explanation: ***If the hands are visibly soiled*** - **Hand rub (alcohol-based hand rub)** is ineffective at removing gross contamination and organic matter from visibly soiled hands. - In such cases, **hand washing with soap and water** is mandatory to physically remove dirt, debris, and microorganisms. *While moving from a contaminated site to a clean site during patient care* - **Hand rub** is appropriate in this scenario to prevent the transfer of microorganisms from a potentially contaminated body site or object to another, cleaner area of the patient. - This is part of the "5 Moments for Hand Hygiene" to ensure **patient safety** and prevent **cross-contamination**. *During direct patient contact* - **Hand rub** can be used before and after direct patient contact if hands are not visibly soiled, as it provides rapid and effective decontamination. - This practice is crucial for minimizing the transmission of **healthcare-associated infections**. *Before donning gloves* - **Hand rub** should be performed before donning gloves, especially when performing procedures that involve contact with mucous membranes, non-intact skin, or sterile sites. - This ensures that hands are clean underneath the gloves, providing an additional layer of **infection prevention**.

Question 257: Match the following: Column A: a. Syphilis b. Chickenpox c. COVID-19 d. Hepatitis A Column B: 1. 6 Days 2. 90 Days 3. 16 Days 4. 28 Days

A. a-2, b-3, c-1, d-4 (Correct Answer)
B. a-3, b-4, c-2, d-1
C. a-1, b-4, c-2, d-3
D. a-3, b-4, c-1, d-2

Explanation: ***a-2, b-3, c-1, d-4*** - **Syphilis**: 90 days represents the **maximum incubation period** for *Treponema pallidum* (range 10-90 days, typical 21 days). While not the most common presentation time, it remains medically accurate and is the only viable match among available options. - **Chickenpox**: 16 days falls within the typical incubation period for **varicella-zoster virus** (range 10-21 days, commonly 14-16 days). - **COVID-19**: 6 days is consistent with the **median incubation period** for SARS-CoV-2 (range 2-14 days, mean 5-6 days). - **Hepatitis A**: 28 days represents the **typical incubation period** for HAV (range 15-50 days, average 28-30 days). *a-3, b-4, c-2, d-1* - Incorrectly assigns **Syphilis** 16 days (below the 10-90 day range's typical value), **COVID-19** 90 days (far exceeding the 2-14 day range), and **Hepatitis A** only 6 days (well below the minimum 15-day period). *a-1, b-4, c-2, d-3* - Incorrectly matches **Syphilis** with 6 days (insufficient for *T. pallidum* to produce primary chancre), **Chickenpox** with 28 days (exceeds the typical VZV range), and **Hepatitis A** with 16 days (below typical range). *a-3, b-4, c-1, d-2* - Incorrectly assigns **Syphilis** 16 days, **Chickenpox** 28 days (exceeding typical range), and **Hepatitis A** 90 days (inconsistent with acute HAV infection pattern).

Question 258: A person is bitten by a dog. The dog and the person are fully immunized. There is a small abrasion mark on the site of bite. What would you advise to the person?

A. Amoxiclav
B. Metronidazole
C. Ciprofloxacin
D. Observation (Correct Answer)

Explanation: ***Observation*** - This is a **Category II exposure** (minor abrasion/scratch) according to **WHO rabies classification**. With both the dog and person **fully immunized**, the recommended management is **immediate wound washing** with soap and water followed by **observation of the dog for 10 days**. - If the dog remains healthy during the 10-day observation period, no further rabies post-exposure prophylaxis is needed. The person's prior vaccination provides adequate protection. - **Prophylactic antibiotics are NOT routinely indicated** for minor abrasions in immunized individuals when the wound can be properly cleaned. The risk of significant bacterial infection in superficial wounds is low with proper wound care. - This approach follows **WHO and IAPSM guidelines** for rational dog bite management, avoiding unnecessary antibiotic use. *Amoxiclav* - Prophylactic antibiotics like **amoxicillin-clavulanate** are reserved for **high-risk wounds**: deep puncture wounds (Category III), wounds near bones/joints, hand/face wounds, delayed presentation (>8 hours), or immunocompromised patients. - A **small abrasion** in an immunized person does not meet criteria for routine antibiotic prophylaxis. Over-prescription contributes to **antimicrobial resistance**. - The primary concern in dog bite management is **rabies prevention**, not routine bacterial prophylaxis for minor wounds. *Metronidazole* - **Metronidazole** alone has limited coverage against common bite wound pathogens and would not be appropriate even if antibiotics were indicated. - It lacks activity against aerobic organisms like *Pasteurella* and *Staphylococcus* species commonly found in dog bites. *Ciprofloxacin* - **Ciprofloxacin** is not the first-line antibiotic for dog bites even when prophylaxis is indicated, due to limited anaerobic and Gram-positive coverage. - More importantly, antibiotics are **not routinely needed** for this Category II exposure with proper wound care and observation.

Question 259: SAFE strategy for trachoma includes all except?

A. Antibiotics
B. Surgery for trichiasis
C. Facial cleanliness
D. Evaluation of control program (Correct Answer)

Explanation: ***Evaluation of control program*** - **Evaluation** is a monitoring and assessment process used to measure the effectiveness of the SAFE strategy, but it is **not one of the four intervention components** of the strategy itself. - The SAFE strategy consists of: **S**urgery, **A**ntibiotics, **F**acial cleanliness, and **E**nvironmental improvement. *Surgery for trichiasis* - **Trichiasis** (in-turned eyelashes) is a blinding complication of trachoma requiring **surgical correction** to prevent corneal damage. - This is the "S" component of SAFE. *Antibiotics* - **Mass drug administration** with **azithromycin** (single oral dose) is used to reduce the community reservoir of *Chlamydia trachomatis*. - This is the "A" component of SAFE. *Facial cleanliness* - Promoting **facial hygiene**, especially in children, prevents transmission of *Chlamydia trachomatis* through contact and fly vectors. - This is the "F" component of SAFE. *Environmental improvement (Not listed as an option but part of SAFE)* - Improving **water supply**, **sanitation**, and **waste management** reduces breeding sites for flies and improves hygiene. - This is the "E" component of SAFE.

Question 260: What is the minimum percentage of partner notification required for effective STI control according to NACO guidelines?

A. 95%
B. 80% (Correct Answer)
C. 65%
D. 50%

Explanation: ***80%*** - NACO guidelines emphasize that a **minimum of 80% partner notification** is required for effective control of sexually transmitted infections (STIs). - Achieving this threshold helps in **breaking the chain of transmission** by identifying and treating exposed individuals. *95%* - While 95% is an aspirational target for some public health interventions, it is not the **minimum required percentage** specifically stated by NACO for effective STI partner notification. - This level of notification would provide even greater control but is often difficult to achieve in practice. *65%* - A 65% partner notification rate is considered **insufficient** by NACO guidelines to effectively control STI transmission within a population. - This rate would likely lead to a significant number of **untreated partners**, allowing the infection to continue spreading. *50%* - A 50% partner notification rate is **far below** the recommended minimum by NACO, making it largely ineffective for STI control. - Such a low rate would result in a substantial number of **missed cases** and ongoing transmission.

Practice by Chapter

Communicable Disease Control Principles

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Vector-Borne Diseases

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Water-Borne Diseases

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Air-Borne Diseases

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Zoonotic Diseases

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Sexually Transmitted Infections

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HIV/AIDS Control Program

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Tuberculosis Control

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Leprosy Elimination

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Emerging and Re-emerging Infections

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Hospital-Acquired Infections

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Integrated Disease Surveillance Project

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