Emerging Viral Infections — MCQs
KFD is transmitted by:
Crimean-Congo Hemorrhagic Fever is transmitted by?
Patient: fever, joint pain, rash. Recent history of mosquito bite. Most likely diagnosis in urban area?
Zoonotic diseases are all except -
Which of the following statements is true regarding the epidemiology of influenza?
Which of the following statements regarding classical Dengue fever is FALSE?
Transition from increased prevalence of infectious and communicable diseases to man-made diseases is known as
Which of the following diseases is caused by the virus shown below?
What should be the minimum value of HbA1c to safely carry out a surgical procedure in an emergency setting?
All are ophthalmological emergencies except -
Emerging Viral Infections Indian Medical PG Practice Questions and MCQs
Question 1: KFD is transmitted by:
- A. Sandfly
- B. Mosquito
- C. Tick (Correct Answer)
- D. Mite
Explanation: ***Tick*** - KFD, or **Kyasanur Forest Disease**, is a viral hemorrhagic fever endemic to India that is primarily transmitted by infected **ticks**, specifically *Haemaphysalis spinigera*. - Humans can contract the disease through a **tick bite** or contact with an **infected animal**, such as monkeys, which are reservoirs for the virus. *Sandfly* - **Sandflies** are vectors for diseases such as **leishmaniasis** and **bartonellosis**, not Kyasanur Forest Disease. - These insects transmit parasites or bacteria, whereas KFD is a **viral infection** transmitted by ticks. *Mosquito* - **Mosquitoes** are common vectors for many viral diseases, including **dengue**, **malaria**, and **chikungunya**, but they do not transmit Kyasanur Forest Disease. - KFD is exclusively associated with **tick transmission** in its endemic regions. *Mite* - **Mites** can transmit diseases like **scrub typhus** (via chiggers) or cause conditions like **scabies**, but they are not vectors for Kyasanur Forest Disease. - The primary vector for KFD is the **hard tick**.
Question 2: Crimean-Congo Hemorrhagic Fever is transmitted by?
- A. Catfish
- B. Mosquitoes
- C. Ticks (Correct Answer)
- D. Mites
Explanation: ***Ticks*** - Crimean-Congo Hemorrhagic Fever (CCHF) is primarily transmitted to humans through the bite of infected **Hyalomma ticks**. - Transmission can also occur through contact with infected animal blood or tissues, or through contact with infected human body fluids. *Cat fish* - **Catfish** are aquatic animals and are not known vectors for the transmission of viral diseases like CCHF. - Their habitat and interaction with humans do not facilitate the spread of tick-borne illnesses. *Mosquitoes* - **Mosquitoes** are vectors for diseases like dengue, malaria, and Zika, but not for CCHF. - CCHF is caused by a Nairovirus, which typically requires a tick vector for its lifecycle and transmission to humans. *Mites* - While some **mites** can transmit diseases (e.g., scrub typhus), they are not the primary or significant vector for Crimean-Congo Hemorrhagic Fever. - The main vector for CCHF is specified as ticks, particularly the Hyalomma genus.
Question 3: Patient: fever, joint pain, rash. Recent history of mosquito bite. Most likely diagnosis in urban area?
- A. Dengue
- B. Japanese Encephalitis
- C. Malaria
- D. Chikungunya (Correct Answer)
Explanation: ***Chikungunya*** - **Chikungunya** is a viral disease transmitted by mosquitoes that commonly presents with **fever**, severe **joint pain** (polyarthralgia), and a **rash**, fitting the patient's symptoms. - Its high prevalence in **urban areas** and recent history of **mosquito bites** make it a strong diagnostic consideration. *Dengue* - While Dengue also causes **fever** [1] and a **rash**, it is more typically associated with **severe muscle and bone pain** ("breakbone fever"), and **hemorrhagic manifestations** or shock, which are not mentioned. - **Joint pain** in dengue is usually less debilitating than in chikungunya. *Japanese Encephalitis* - This is a serious **neurological infection** characterized by **fever**, **headache**, seizures, and altered mental status, rather than prominent joint pain and rash. - It primarily affects the **brain** and is less likely to present with this specific symptom triad. *Malaria* - Malaria is characterized by **cyclic fevers**, chills, sweating, and fatigue, but typically **does not present with a rash** [1] or significant joint pain. - It is caused by a **parasite** transmitted by *Anopheles* mosquitoes, and its clinical picture differs from the described symptoms.
Question 4: Zoonotic diseases are all except -
- A. Q fever
- B. Typhoid (Correct Answer)
- C. Anthrax
- D. Rabies
Explanation: ***Typhoid*** - Typhoid fever is a **bacterial infection** caused by *Salmonella Typhi*, which is spread through contaminated food and water, primarily from human waste. - It is an exclusively **human disease**, meaning there is no animal reservoir involved in its transmission to humans. *Q fever* - Q fever is a **zoonotic disease** caused by the bacterium *Coxiella burnetii*, primarily spread from livestock (cattle, sheep, goats) to humans. - Transmission generally occurs through inhalation of contaminated aerosols from animal excreta or birth products. *Anthrax* - Anthrax is a serious **zoonotic disease** caused by the bacterium *Bacillus anthracis*, which can affect both animals and humans. - Humans usually contract anthrax through contact with infected animals or contaminated animal products. *Rabies* - Rabies is a fatal **viral zoonotic disease** that is transmitted to humans through the saliva of infected animals, most commonly from dog bites. - Wild animals like bats, raccoons, and foxes are important reservoirs for the rabies virus.
Question 5: Which of the following statements is true regarding the epidemiology of influenza?
- A. Pandemics cannot occur with influenza viruses.
- B. Incubation period is typically 7-10 days.
- C. Humans are the only reservoir for influenza.
- D. Asymptomatic cases can occur and may contribute to transmission. (Correct Answer)
Explanation: ***Asymptomatic cases can occur and may contribute to transmission.*** - Asymptomatic or mildly symptomatic individuals can shed the virus, contributing to the silent spread of influenza within a community. - This characteristic makes **influenza control** challenging, as not all infected individuals seek medical attention or are easily identified. *Incubation period is typically 7-10 days.* - The typical incubation period for influenza is much shorter, usually **1 to 4 days**, with an average of 2 days. - A 7-10 day incubation period is more characteristic of infections like **measles** or **mumps**, not influenza. *Pandemics cannot occur with influenza viruses.* - Influenza viruses are well-known for their potential to cause **pandemics** through antigenic shifts, leading to novel strains against which the population has little to no immunity. - Historically, there have been several major influenza pandemics, such as the **1918 Spanish Flu** and the 2009 H1N1 pandemic. *Humans are the only reservoir for influenza.* - While humans are a significant reservoir, influenza viruses also circulate in **animal reservoirs** such as birds (especially wild aquatic birds) and pigs. - These animal reservoirs can serve as sources for new human strains through **inter-species transmission** and genetic reassortment.
Question 6: Which of the following statements regarding classical Dengue fever is FALSE?
- A. Positive tourniquet test (Correct Answer)
- B. Low case fatality rate
- C. Self limiting disease
- D. Transmitted by Aedes aegypti
Explanation: **CRITICAL ISSUE:** This question as currently written is problematic because **all four statements are TRUE** about classical dengue fever, making it impossible to identify a FALSE statement. ***Analysis of Each Statement:*** **Positive tourniquet test** (Currently marked as answer) - This is actually a **TRUE statement** about classical dengue fever - The tourniquet test is **positive in classical dengue fever** and is used as a diagnostic criterion by WHO - A positive tourniquet test indicates capillary fragility and is seen in both classical dengue and DHF - **This should NOT be the answer** to a FALSE question **Low case fatality rate** - TRUE statement: Classical dengue fever has a very low case fatality rate (<1%) with proper supportive care - Mortality is primarily associated with severe dengue/DHF/DSS **Self limiting disease** - TRUE statement: Classical dengue is typically self-limiting, resolving within 7-10 days with symptomatic treatment - Characterized by fever, headache, retro-orbital pain, myalgia, and rash **Transmitted by Aedes aegypti** - TRUE statement: **Aedes aegypti** is the primary vector for dengue transmission - Also transmitted by Aedes albopictus in some regions - Day-biting mosquitoes found in urban/semi-urban areas **RECOMMENDATION:** This question needs revision as it currently has no correct answer. All options are true statements about classical dengue fever.
Question 7: Transition from increased prevalence of infectious and communicable diseases to man-made diseases is known as
- A. Demographic transition
- B. Paradoxical transition
- C. Epidemiological transition (Correct Answer)
- D. Reversal of transition
Explanation: ***Epidemiological transition*** - This term describes the shift in **disease patterns** observed in many populations, moving from a predominance of **infectious and communicable diseases** to an increased prevalence of **chronic, non-communicable diseases** (often described as "man-made" due to their association with lifestyle and environmental factors). - This transition is typically linked to advancements in **public health**, sanitation, medicine, and changes in socioeconomic status. *Demographic transition* - This concept describes the historical shift from high **birth rates** and **death rates** to low birth rates and death rates as a country develops from a pre-industrial to an industrialized economic system. - While related to disease patterns through changes in population structure, it directly focuses on **population growth** and age distribution, not specific disease prevalence. *Paradoxical transition* - This is not a recognized or standard public health or demographic term for the described phenomenon. - The term "paradoxical" would imply a contradictory or unexpected outcome, which is not the primary descriptor for the shift in disease patterns. *Reversal of transition* - This term would imply a return to previous patterns, such as an increase in **infectious diseases** after a period of decline. - While possible in specific contexts (e.g., due to antibiotic resistance or weakened public health systems), it does not describe the initial shift from infectious to man-made diseases.
Question 8: Which of the following diseases is caused by the virus shown below?
- A. Neurodegenerative disorder
- B. Swimming pool conjunctivitis (Correct Answer)
- C. Solid organ graft infection
- D. Solid organ graft rejection
Explanation: ***Swimming pool conjunctivitis*** - The image displays an **adenovirus**, characterized by its **icosahedral shape** and distinct **fiber proteins** projecting from the vertices. - Adenoviruses are a common cause of **pharyngoconjunctival fever**, often referred to as "swimming pool conjunctivitis" due to its spread in **inadequately chlorinated swimming pools**. - This is the **most characteristic disease** associated with adenovirus infection, particularly serotypes **3, 4, and 7**. *Neurodegenerative disorder* - Adenoviruses are **not associated** with neurodegenerative disorders. - Neurodegenerative conditions are typically linked to **prions, misfolded proteins**, or other viral agents like **JC virus** (progressive multifocal leukoencephalopathy). - Adenoviruses cause **acute infections**, not chronic neurodegeneration. *Solid organ graft infection* - While adenoviruses can cause severe infections in **immunocompromised patients**, including transplant recipients, this is not their most characteristic presentation. - In transplant patients, adenovirus may cause **colitis, hepatitis, or nephritis**, but these are **opportunistic infections** rather than the typical disease association. - The characteristic disease remains **conjunctivitis and respiratory infections** in immunocompetent hosts. *Solid organ graft rejection* - **Graft rejection** is an **immunological process** where the recipient's immune system attacks the transplanted organ, not a viral infection. - Adenovirus does not directly cause the mechanism of graft rejection. - While viral infections may complicate graft outcomes, rejection itself is **immune-mediated**, not infectious.
Question 9: What should be the minimum value of HbA1c to safely carry out a surgical procedure in an emergency setting?
- A. <7
- B. <8
- C. <10 (Correct Answer)
- D. <8
Explanation: ***<10*** - In an **emergency setting**, the priority is to proceed rapidly with surgery; current guidelines suggest that an **HbA1c <10%** is acceptable to proceed without significant delay for optimization. - While lower HbA1c is ideal, delaying an emergency procedure to achieve an HbA1c below 10% is generally **not recommended**, as the benefits of urgent surgery outweigh the risks associated with this level of glycemic control [1]. *<7* - An HbA1c of **<7% is the general target** for optimal glycemic control in most diabetic patients, especially in an elective setting. - Achieving this level in an emergency would likely require **delaying surgery**, which is not feasible or safe when immediate intervention is needed. *<8* - An HbA1c of **<8%** represents good control for many individuals, particularly older adults or those with comorbidities. - While better than 10%, it is not the absolute minimum required to proceed with an **emergency surgery**, as timely intervention is paramount. *<8* - An HbA1c of **<8%** represents good control for many individuals, particularly older adults or those with comorbidities. - While better than 10%, it is not the absolute minimum required to proceed with an **emergency surgery**, as timely intervention is paramount.
Question 10: All are ophthalmological emergencies except -
- A. Endophthalmitis
- B. CRVO (Correct Answer)
- C. Acute congestive glaucoma
- D. CRAO
Explanation: ***CRVO*** - Central Retinal Vein Occlusion (CRVO) is characterized by painless **vision loss** due to retinal hemorrhage and edema, but it is generally *not* considered an immediate, vision-threatening emergency in the same vein as the other options. - While it requires prompt evaluation and management to preserve vision, CRVO allows for a less urgent intervention compared to conditions that can lead to permanent vision loss within hours. *Endophthalmitis* - **Endophthalmitis** is a severe inflammation of the intraocular fluids and tissues, typically caused by infection, and can lead to rapid and irreversible vision loss if not treated urgently. - It presents with pain, redness, reduced vision, and hypopyon (pus in the anterior chamber), necessitating immediate antibiotic treatment and surgical intervention. *Acute congestive glaucoma* - **Acute congestive glaucoma** (acute angle-closure glaucoma) involves a sudden increase in intraocular pressure, causing severe pain, redness, corneal edema, and profound vision loss. - If left untreated, the high pressure can cause irreversible damage to the optic nerve within hours, making it a true ocular emergency. *CRAO* - **Central Retinal Artery Occlusion (CRAO)** is a sudden, painless loss of vision in one eye due to blockage of the central retinal artery, leading to retinal ischemia. - It is an ocular emergency because irreversible retinal damage and vision loss can occur within 90-120 minutes of the occlusion, requiring immediate intervention to restore blood flow.
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