Vector-Borne Disease Shifts — MCQs
Which of the following viral infections is transmitted by tick?
Patient: fever, joint pain, rash. Recent history of mosquito bite. Most likely diagnosis in urban area?
NVBDCP includes all except ?
Kala azar is transmitted by:
Trypanosoma cruzi is transmitted by which of the following?
Which of the following is the most important indicator for measuring the communicability of a disease?
The best indicator for a potential explosiveness of plague outbreak is:
Emergency or re-emergence seen in which of the following organisms? a) Polio virus b) Measles virus c) Nipah virus d) West Nile virus e) Ebola virus
With regard to the Goals, Milestones and Targets for the Global Technical Strategy for Malaria (2016-2030), consider the following statements: 1. Compared to 2015, the target is to reduce the malaria mortality rates globally by at least 90% by year 2030 2. Compared to 2015, the target is to reduce malaria case incidence by 90% by year 2030 3. Eliminate malaria from at least 35 countries, where malaria was transmitted in 2015, by year 2030 Which of the above statements hold true?
What is true about global warming?
Vector-Borne Disease Shifts Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following viral infections is transmitted by tick?
- A. Ehrlichiosis
- B. Lyme disease
- C. Rocky Mountain spotted fever
- D. Kyasanur forest disease (KFD) (Correct Answer)
Explanation: ***Kyasanur forest disease (KFD)*** - KFD is a **viral hemorrhagic fever** caused by the Kyasanur Forest disease virus, a member of the *Flaviviridae* family. - It is primarily transmitted to humans through the bite of infected **ticks**, especially *Haemaphysalis spinigera*. *Ehrlichiosis* - Ehrlichiosis is a **bacterial infection** caused by *Ehrlichia* species, not a viral infection. - It is transmitted by **ticks**, primarily the **lone star tick** (*Amblyomma americanum*). *Lyme disease* - Lyme disease is a **bacterial infection** caused by *Borrelia burgdorferi*, not a viral infection. - It is transmitted by **ticks**, notably the **black-legged tick** (*Ixodes scapularis*). *Rocky Mountain spotted fever* - Rocky Mountain spotted fever (RMSF) is a **bacterial infection** caused by *Rickettsia rickettsii*, not a viral infection. - It is transmitted by **ticks**, such as the **American dog tick**, **Rocky Mountain wood tick**, and **brown dog tick**.
Question 2: 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 3: NVBDCP includes all except ?
- A. Filariasis
- B. Malaria
- C. Kala-azar
- D. Yellow fever (Correct Answer)
Explanation: ***Yellow fever*** - Yellow fever is a **viral hemorrhagic fever** transmitted by infected mosquitoes, primarily **Aedes aegypti**. - While a significant public health concern, it is **not included in India's National Vector-Borne Disease Control Programme (NVBDCP)**, as it is not endemic to India. *Filariasis* - **Lymphatic filariasis** (elephantiasis) is a major vector-borne disease in India, caused by parasitic worms transmitted by mosquitoes. - It is a key component of the NVBDCP, which focuses on its elimination through **mass drug administration** and vector control. *Malaria* - **Malaria**, caused by Plasmodium parasites transmitted by Anopheles mosquitoes, is a cornerstone of the NVBDCP. - The program actively implements strategies for **case detection, treatment, vector control**, and preventing outbreaks. *Kala-azar* - **Kala-azar** (visceral leishmaniasis) is a severe parasitic disease transmitted by **sandflies**, making it a vector-borne disease. - It is one of the six diseases targeted by the NVBDCP for elimination, particularly in endemic regions of India.
Question 4: Kala azar is transmitted by:
- A. Tse tse fly
- B. Sandfly (Correct Answer)
- C. Hard tick
- D. Culex mosquito
Explanation: ***Sandfly*** - **Kala azar**, also known as **visceral leishmaniasis**, is a severe parasitic disease caused by **Leishmania donovani**. - This parasite is transmitted to humans through the bite of an infected female **phlebotomine sandfly**. *Tse tse fly* - The **tse tse fly** is the vector for **African trypanosomiasis**, also known as **sleeping sickness**. - It transmits **Trypanosoma brucei**, a different parasitic organism than the one causing kala azar. *Hard tick* - **Hard ticks** are vectors for several diseases, including **Lyme disease** (Borrelia burgdorferi), **Rocky Mountain spotted fever** (Rickettsia rickettsii), and **anaplasmosis**. - They are not associated with the transmission of leishmaniasis. *Culex mosquito* - The **Culex mosquito** is a common vector for diseases such as **West Nile virus**, **Japanese encephalitis**, and **filariasis**. - It does not transmit the **Leishmania parasite** responsible for kala azar.
Question 5: Trypanosoma cruzi is transmitted by which of the following?
- A. Tse tse fly
- B. Reduviid bug (Correct Answer)
- C. Culex mosquito
- D. Sand fly
Explanation: ***Reduviid bug*** - *Trypanosoma cruzi*, the causative agent of **Chagas disease**, is primarily transmitted to humans through the feces of infected **reduviid bugs**, also known as **kissing bugs**. - The bug typically bites a person, often around the face, and then defecates near the bite wound, allowing the parasite to enter when the person scratches or rubs the area. *Tse tse fly* - The **tsetse fly** is the vector for **African trypanosomiasis** (sleeping sickness), caused by *Trypanosoma brucei*. - This fly is geographically restricted to sub-Saharan Africa, whereas *Trypanosoma cruzi* is prevalent in the Americas. *Culex mosquito* - **Culex mosquitoes** are known vectors for various diseases, including **West Nile virus**, **Japanese encephalitis**, and **filariasis**. - They are not involved in the transmission of *Trypanosoma cruzi*. *Sand fly* - **Sand flies** transmit **Leishmaniasis**, a parasitic disease caused by various species of *Leishmania*. - They are also responsible for transmitting **Bartonellosis** and some types of **Arboviruses**, but not Chagas disease.
Question 6: Which of the following is the most important indicator for measuring the communicability of a disease?
- A. Prevalence rate
- B. Incidence rate
- C. Secondary attack rate (Correct Answer)
- D. Primary attack rate
Explanation: ***Secondary attack rate*** - The **secondary attack rate** directly measures the proportion of susceptible individuals who develop a disease after being exposed to a primary case. - It is a crucial indicator of a disease's **communicability** or **contagious spread** within a close-contact group. *Prevalence rate* - **Prevalence rate** describes the total number of existing cases in a population at a specific time or over a period. - While useful for disease burden, it does not specifically indicate how easily a disease spreads from person to person. *Incidence rate* - The **incidence rate** measures the rate at which new cases of a disease occur in a population over a specified period. - It reflects the risk of contracting a disease but doesn't directly quantify person-to-person transmissibility in close contacts. *Primary attack rate* - The **primary attack rate** is often used interchangeably with incidence rate during an outbreak, referring to the proportion of exposed individuals who become ill. - While related to new cases, it doesn't specifically target the spread from a known primary case to secondary contacts.
Question 7: The best indicator for a potential explosiveness of plague outbreak is:
- A. Burrow index
- B. Cheopis index (Correct Answer)
- C. Specific percentage of fleas
- D. Total flea index
Explanation: ***Cheopis index*** - The **Cheopis index** (average number of *Xenopsylla cheopis* fleas per rodent) is the **best indicator for explosive plague outbreaks**. - *X. cheopis* (oriental rat flea) is the **primary vector** of *Yersinia pestis* and most efficient at transmission. - When the Cheopis index **exceeds 1.0**, it indicates critical conditions for rapid epidemic spread and explosive outbreak potential. - This index specifically measures the most dangerous vector species, making it the most precise predictor of outbreak explosiveness. *Total flea index* - Measures the average number of **all flea species** per rodent, regardless of vector competence. - While useful for general surveillance, it **lacks specificity** as it includes non-vector or less efficient vector species. - Does not specifically predict explosiveness as effectively as focusing on the primary vector species. *Burrow index* - Reflects rodent population density and activity (number of active burrows per hectare). - Indicates **host availability** but not the immediate transmission risk from vectors. - Important for understanding epizootic conditions but indirect measure of outbreak potential. *Specific percentage of fleas* - This term is **vague and non-standard** in plague epidemiology terminology. - Could refer to various metrics (percentage infected, percentage of specific species) without clear definition. - Not a recognized standardized indicator for plague surveillance.
Question 8: Emergency or re-emergence seen in which of the following organisms? a) Polio virus b) Measles virus c) Nipah virus d) West Nile virus e) Ebola virus
- A. abd
- B. Hepatitis B virus
- C. bde
- D. cde (Correct Answer)
Explanation: ***cde*** - **Nipah virus** is a well-known **emerging infectious disease** due to spillover from animal reservoirs. - **West Nile virus** is considered a **re-emerging pathogen** that has spread globally, causing outbreaks. - **Ebola virus** is famously associated with several **re-emergence events** in Africa, characterized by high fatality rates. *abd* - **Polio virus** is targeted for eradication and, while still circulating in some regions, is not typically classified as an emerging or re-emerging disease in the same context as the others. - **Measles virus** is a vaccine-preventable disease that can cause outbreaks due to waning immunity or unvaccinated populations, but its pattern is more of a persistent public health challenge rather than true emergence/re-emergence. *Hepatitis B virus* - **Hepatitis B virus** is a chronic global health burden but is not considered an emerging or re-emerging virus; it has been endemic for many decades. - Its transmission patterns and epidemiological profile are well-established. *bde* - **Measles virus**, as mentioned, is not typically categorized as an emerging or re-emerging infectious disease. - The combination here incorrectly groups measles with true emerging/re-emerging pathogens. *ade* - **Polio virus** is primarily a target for eradication, not an emerging or re-emerging pathogen. - This option incorrectly includes polio within the category of emerging/re-emerging diseases.
Question 9: With regard to the Goals, Milestones and Targets for the Global Technical Strategy for Malaria (2016-2030), consider the following statements: 1. Compared to 2015, the target is to reduce the malaria mortality rates globally by at least 90% by year 2030 2. Compared to 2015, the target is to reduce malaria case incidence by 90% by year 2030 3. Eliminate malaria from at least 35 countries, where malaria was transmitted in 2015, by year 2030 Which of the above statements hold true?
- A. 1 and 3 only
- B. 1 and 2 only
- C. 2 and 3 only
- D. 1, 2 and 3 (Correct Answer)
Explanation: ***1, 2 and 3*** - All three statements accurately reflect the **core targets** set by the Global Technical Strategy for Malaria (2016-2030). - These ambitious goals aim to achieve significant reductions in malaria burden and eventual eradication in many regions. *1 and 3 only* - This option is incorrect because it omits statement 2, which is a verified goal for **reducing malaria case incidence**. - All three statements are indeed part of the strategy's published objectives. *1 and 2 only* - This option is incorrect as it excludes statement 3 regarding the **elimination of malaria** from at least 35 countries. - The strategy encompasses all three stated objectives for global malaria control. *2 and 3 only* - This option is incorrect because it fails to include statement 1, which specifies the target for **reducing malaria mortality rates**. - The strategy explicitly addresses all three aspects: mortality, incidence, and country-level elimination.
Question 10: What is true about global warming?
- A. Carbon dioxide is the major greenhouse gas. (Correct Answer)
- B. The stratosphere ozone layer is harmful.
- C. Chlorofluorocarbons (CFCs) increase the stratosphere ozone layer.
- D. The Kyoto Protocol called for a 20% reduction in the greenhouse effect.
Explanation: ### Explanation **1. Why Option A is Correct:** Global warming is primarily driven by the **Greenhouse Effect**, where certain gases trap infrared radiation (heat) in the Earth's atmosphere. **Carbon dioxide ($CO_2$)** is the most significant greenhouse gas, contributing approximately **60%** to the global warming effect. While other gases like methane ($CH_4$) have higher global warming potential per molecule, the sheer volume of $CO_2$ emitted from fossil fuel combustion and deforestation makes it the major driver of climate change. **2. Why the Other Options are Incorrect:** * **Option B:** The **stratospheric ozone layer** is beneficial, not harmful. It acts as a protective shield, absorbing 97–99% of the sun's high-frequency ultraviolet (UV) radiation. Harmful ozone is found in the **troposphere** (ground level), where it acts as a pollutant and respiratory irritant. * **Option C:** Chlorofluorocarbons (CFCs) **decrease** the stratospheric ozone layer. When CFCs reach the stratosphere, they release chlorine atoms that catalyze the breakdown of ozone ($O_3$) into oxygen ($O_2$), leading to "ozone holes." * **Option D:** The **Kyoto Protocol (1997)** aimed for a global reduction of greenhouse gas emissions by an average of **5.2%** below 1990 levels by 2012, not 20%. **3. High-Yield Facts for NEET-PG:** * **Greenhouse Gases (GHGs) in order of contribution:** $CO_2$ (60%) > Methane (20%) > Nitrous Oxide (6%) > CFCs (14%). * **Health Impacts:** Climate change expands the geographical range of vector-borne diseases (e.g., Malaria, Dengue) and increases the frequency of heatwaves and extreme weather events. * **Montreal Protocol:** Focused on substances that deplete the ozone layer (CFCs). * **Paris Agreement (2015):** Aims to limit global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels.
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