Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 541: Scrub typhus is transmitted by:

A. Louse
B. Tick
C. Mite (Correct Answer)
D. Flea

Explanation: ***Mite*** - Scrub typhus is caused by **Orientia tsutsugamushi**, which is transmitted to humans by the bite of infected larval trombiculid mites, also known as **chiggers**. - These mites typically inhabit areas with **dense vegetation** and are commonly found in rural or forested regions. - The **eschar** (black necrotic lesion) at the bite site is a characteristic feature of scrub typhus. *Louse* - **Lice** are known vectors for diseases such as **epidemic typhus** (caused by Rickettsia prowazekii) and **relapsing fever** (caused by Borrella recurrentis). - They do not transmit **scrub typhus**. *Tick* - **Ticks** are vectors for a variety of rickettsial diseases, including **Rocky Mountain spotted fever** (R. rickettsii), **Indian tick typhus** (R. conorii), and **ehrlichiosis**. - While ticks transmit other typhus-like illnesses, they are not responsible for transmitting **scrub typhus**. *Flea* - **Fleas** are vectors for **murine typhus** (caused by Rickettsia typhi) and **plague** (caused by Yersinia pestis). - They do not transmit **scrub typhus**, which is specifically transmitted by mites.

Question 542: Mass Drug Administration is NOT routinely used as the primary strategy for:

A. Vitamin A Deficiency
B. Scabies (Correct Answer)
C. Lymphatic Filariasis
D. Worm infestation

Explanation: ***Scabies*** - While **mass drug administration with oral ivermectin** has shown effectiveness in specific endemic outbreak settings, MDA is generally **not the primary recommended strategy** for routine scabies control in most public health contexts. - Scabies control typically prioritizes **case finding, contact tracing, simultaneous household treatment, and environmental decontamination**—which are more complex to implement than standard MDA programs. - Unlike the other conditions listed, scabies lacks well-established **routine MDA programs** at the scale of national public health initiatives, making it the least suitable option for MDA among these choices. *Vitamin A Deficiency* - **Vitamin A supplementation** through MDA is a **highly effective and widely implemented** WHO-recommended strategy to combat Vitamin A deficiency in at-risk populations, particularly children under 5 years. - Regular mass supplementation helps prevent **xerophthalmia** and reduces morbidity and mortality from infectious diseases. - This is a cornerstone of routine public health programs globally. *Lymphatic Filariasis* - **Lymphatic filariasis** is a classic example where MDA with anti-filarial drugs like **diethylcarbamazine (DEC), albendazole,** or **ivermectin** is the cornerstone strategy for interrupting transmission. - MDA is the **primary WHO-recommended approach** to achieve elimination of lymphatic filariasis, with established national programs in endemic countries. *Worm infestation* - **Mass deworming programs** using drugs like **albendazole** or **mebendazole** represent highly effective and well-established forms of MDA for controlling **soil-transmitted helminth infections**. - These routine programs significantly reduce disease burden in school-aged children, improving nutritional status, growth, and learning outcomes.

Question 543: Vision 2020 aims to eliminate which infectious cause of preventable blindness by 2020?

A. Refractive errors
B. Vitamin A deficiency
C. Onchocerciasis
D. Trachoma (Correct Answer)

Explanation: **Correct: Trachoma** - **Vision 2020: The Right to Sight** is a global initiative launched by the WHO and the International Agency for the Prevention of Blindness (IAPB) to eliminate the main causes of avoidable blindness by the year 2020. - **Trachoma** was identified as one of the major infectious causes of preventable blindness and was a primary target for elimination under the Vision 2020 initiative through the **SAFE strategy (Surgery, Antibiotics, Facial Cleanliness, Environmental Improvements)**. - Among infectious causes, trachoma was specifically highlighted for elimination due to its widespread prevalence and feasibility of elimination through proven public health interventions. *Incorrect: Refractive errors* - While a significant cause of visual impairment, refractive errors are not an infectious cause of blindness. - They are primarily corrected with glasses, contact lenses, or refractive surgery. *Incorrect: Vitamin A deficiency* - Vitamin A deficiency is a major nutritional cause of preventable blindness, especially in children, leading to conditions like **xerophthalmia** and keratomalacia. - Though preventable, it is not an infectious cause, unlike trachoma. *Incorrect: Onchocerciasis* - Also known as "river blindness," **onchocerciasis** is an infectious disease caused by the parasite *Onchocerca volvulus*, transmitted by blackflies, and can lead to blindness. - While part of Vision 2020 control programs, trachoma was the infectious cause specifically targeted for elimination by 2020 due to its feasibility with the SAFE strategy.

Question 544: Regarding Influenza, which statement is not true?

A. Virus shedding present before the patient presents with symptoms
B. Aquatic birds are reservoir
C. Secondary attack rate 5-15%
D. 1-5 years age is not a high risk age group (Correct Answer)

Explanation: ***1-5 years age is not a high risk age group*** (This statement is FALSE - making it the correct answer) - Children aged **1-5 years ARE considered a high-risk group** for severe influenza and its complications. - They often require **hospitalization** and may experience complications such as pneumonia, otitis media, and seizures. - This statement is incorrect, which is why it's the answer to "which is NOT true." *Virus shedding present before the patient presents with symptoms* (This statement is TRUE) - Influenza is highly contagious, and patients typically shed the **virus for 1 to 2 days before the onset of symptoms.** - This **presymptomatic shedding** contributes significantly to the rapid spread of the virus. *Aquatic birds are reservoir* (This statement is TRUE) - **Wild aquatic birds** are the natural reservoir for most influenza A viruses, particularly those with a broad range of hemagglutinin (HA) and neuraminidase (NA) subtypes. - They can carry influenza viruses without becoming ill, contributing to the **genetic diversity and evolution of new strains.** *Secondary attack rate 5-15%* (This statement is TRUE) - The **secondary attack rate** for influenza in households and close contacts is typically estimated to be between 5% and 15%. - This rate indicates the **likelihood of transmission** from an infected individual to susceptible household members or close contacts.

Question 545: Malaria control means

A. To prevent local transmission for 3 years
B. To reduce Incidence to Zero
C. To reduce Malaria mortality to Zero
D. To reduce Malaria disease so that it's no longer a Public Health Problem (Correct Answer)

Explanation: ***To reduce Malaria disease so that it's no longer a Public Health Problem*** - Malaria control aims to significantly **decrease morbidity and mortality** due to malaria, reducing its overall impact on public health. - The goal is to lower disease burden to a level where it no longer poses a major threat to the population, often through methods like **vector control** and **prompt treatment**. *To prevent local transmission for 3 years* - This definition is more aligned with **malaria elimination**, which seeks to interrupt local transmission for a specific period (often 3 years) in a defined geographical area. - **Malaria control** is a broader and less stringent objective than elimination. *To reduce Incidence to Zero* - Reducing incidence to zero signifies **malaria elimination** or eradication, a more ambitious goal than control. - Control focuses on **managing the disease burden** rather than completely halting new cases. *To reduce Malaria mortality to Zero* - While reducing mortality is a key component of malaria control, aiming for **zero deaths** is an exceptionally challenging target that is more indicative of elimination or eradication efforts. - Control primarily focuses on **reducing deaths and illness** to manageable levels.

Question 546: Which of the following diseases is not included in the National Vector Borne Disease Control Program?

A. Tuberculosis (Correct Answer)
B. Japanese encephalitis
C. Malaria
D. Dengue

Explanation: ***Tuberculosis*** - **Tuberculosis** is a bacterial infection primarily affecting the lungs and is not transmitted by a vector. - It is controlled under the **National TB Elimination Programme (NTEP)**, a separate national health program. *Japanese encephalitis* - **Japanese encephalitis** is a viral disease transmitted by mosquitoes, making it a vector-borne disease. - It is one of the diseases specifically targeted by the **National Vector Borne Disease Control Program (NVBDCP)**. *Malaria* - **Malaria** is a parasitic disease transmitted by Anopheles mosquitoes, clearly categorizing it as vector-borne. - It is a primary focus of the **NVBDCP** due to its significant public health impact. *Dengue* - **Dengue** is a viral disease transmitted by Aedes mosquitoes, hence a vector-borne disease. - **Dengue control and prevention** are key objectives of the **NVBDCP**.

Question 547: Which of the following is the most effective method to prevent malaria?

A. Vaccination
B. Antimalarial drugs
C. Genetic modification of mosquitoes
D. Use of insecticide-treated nets (Correct Answer)

Explanation: ***Use of insecticide-treated nets*** - **Insecticide-treated nets (ITNs)** provide a physical and chemical barrier against **Anopheles mosquitoes**, the primary vectors of malaria, reducing human-vector contact effectively during sleep. - The insecticide on the nets kills or repels mosquitoes, preventing bites and reducing the **mosquito population** within homes and surrounding areas. *Vaccination* - While significant progress has been made with **malaria vaccines** like RTS,S/AS01 (Mosquirix), their **efficacy is partial** (around 30-40% effective against severe malaria over several years) and requires multiple doses. - It is an important complementary tool but **not yet the most effective standalone method** for preventing widespread malaria transmission compared to vector control. *Antimalarial drugs* - **Antimalarial drugs** are primarily used for **treatment** of active malaria infections or for **chemoprophylaxis** (preventive treatment) in travelers or specific high-risk populations. - While effective for individual prevention during travel or in specific scenarios, widespread prophylactic use is **not a sustainable or most effective primary public health strategy** for preventing malaria transmission across entire communities due to cost, drug resistance, and adherence issues. *Genetic modification of mosquitoes* - **Genetic modification of mosquitoes** (e.g., using **gene drives** to reduce mosquito populations or render them incapable of transmitting malaria) is a promising but **experimental strategy** under development. - It involves significant ethical, ecological, and regulatory challenges, and is **not currently an implemented or widely available method** for malaria prevention.

Question 548: Which of the following diseases is primarily monitored under the Integrated Disease Surveillance Program (IDSP)?

A. Tuberculosis
B. HIV
C. Malaria (Correct Answer)
D. Diabetes

Explanation: ***Malaria*** - Malaria is a significant public health concern with high incidence and mortality, making its surveillance crucial for **disease control and elimination efforts**. - The IDSP aims for early detection and rapid response to **outbreaks of communicable diseases**, including vector-borne diseases like malaria. *Tuberculosis* - While a major public health issue, **tuberculosis (TB)** is primarily monitored under the **National Tuberculosis Elimination Programme (NTEP)**, which has a dedicated and extensive surveillance system. - The NTEP focuses on active case finding, treatment, and prevention of TB through a specific, robust framework separate from the IDSP's general surveillance. *HIV* - **HIV/AIDS** surveillance is conducted under the **National AIDS Control Organisation (NACO)**, which has a specialized program for monitoring prevalence, incidence, and risk behaviors. - NACO's surveillance includes sentinel surveillance among specific populations and programmatic data collection, distinct from the IDSP's generalized infectious disease monitoring. *Diabetes* - **Diabetes** is a **non-communicable disease** and is not primarily monitored under the IDSP, which focuses on infectious disease outbreaks. - Surveillance for non-communicable diseases like diabetes typically falls under programs dedicated to non-communicable disease prevention and control, focusing on prevalence and risk factors.

Question 549: What is the primary purpose of hand hygiene in healthcare settings?

A. Increases staff productivity
B. Improves patient satisfaction
C. Reduces medication errors
D. Prevents nosocomial infections (Correct Answer)

Explanation: ***Prevents nosocomial infections*** - Hand hygiene is a cornerstone of **infection control**, significantly reducing the transmission of **pathogens** between patients and healthcare workers. - By mechanically removing or inactivating microorganisms on the hands, it directly **interrupts the chain of infection** in healthcare settings. *Increases staff productivity* - While a healthy workforce is more productive, hand hygiene's primary goal is not directly to increase **staff output**. - Its main focus is on patient and staff safety through **infection prevention**. *Improves patient satisfaction* - Patients may appreciate healthcare workers practicing good hand hygiene, but improving **patient satisfaction scores** is a secondary effect, not its core purpose. - The direct, measurable impact of hand hygiene is on **health outcomes** related to infection. *Reduces medication errors* - **Medication errors** are primarily prevented through careful prescription, dispensing, administration, and verification processes. - Hand hygiene plays no direct role in preventing these types of clinical errors.

Question 550: In a community experiencing an outbreak of meningitis, which preventive measure is most effective in controlling the spread of the disease?

A. Hand washing
B. Vaccination (Correct Answer)
C. Antibiotic prophylaxis
D. Quarantine of affected individuals

Explanation: ***Vaccination*** - **Vaccination** is the most effective community-level strategy for controlling and halting the spread of meningitis during an outbreak by rapidly reducing the pool of susceptible individuals. - Mass vaccination campaigns during outbreaks create **herd immunity**, which interrupts transmission chains and prevents the outbreak from spreading further in the community. - Unlike individual contact management, vaccination provides **population-wide protection** and long-term immunity, addressing both current and future transmission. - Successful outbreak control examples include the African meningitis belt campaigns where mass vaccination effectively controlled epidemics. *Antibiotic prophylaxis* - **Antibiotic prophylaxis** is crucial for managing close contacts of confirmed cases to prevent secondary spread, but it's a **contact management strategy** rather than a community-wide control measure. - It provides only short-term protection (no lasting immunity) and cannot be feasibly administered to entire communities during widespread outbreaks. - Overuse can lead to **antibiotic resistance** and it doesn't prevent new infections in the broader susceptible population. - Best used as an adjunct to vaccination, not as the primary outbreak control strategy. *Hand washing* - While important for general hygiene and reducing the spread of many infections, **hand washing** is less effective for controlling meningitis outbreaks. - Meningitis is primarily spread through **respiratory droplets and direct contact with secretions**, not hand-to-mouth transmission. - Cannot provide specific immunity against meningococcal or pneumococcal bacteria that commonly cause meningitis. *Quarantine of affected individuals* - **Quarantine** may help limit direct transmission from infected individuals, but it's difficult to implement effectively on a large scale for community outbreaks. - Meningitis patients are typically hospitalized and isolated as part of standard care, but this alone doesn't prevent new cases in the susceptible population. - Doesn't address the carrier state (asymptomatic carriers can transmit disease) or provide immunity to at-risk populations.

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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