Infectious Diseases Practice Questions

Q: Which of the following statements regarding Anopheles Fluviatilis is INCORRECT?

It is restricted to the Andaman and Nicobar Islands.. ### Explanation **1. Why Option D is the Correct (Incorrect Statement):** *Anopheles fluviatilis* is one of the most important primary vectors of malaria in India, but it is **not** restricted to the Andaman and Nicobar Islands. It is widely distributed across the **foothills and hilly tracts** of mainland India, particularly in the Western Ghats, Nilgiris, and Central Indian ranges. The vector specifically restricted to the Andaman and Nicobar Islands is *Anopheles sundaicus*. **2. Analysis of Other Options:** * **Option A (Breeding):** This is a correct statement. *A. fluviatilis* typically breeds in **slow-moving, clear water** such as hill streams, irrigation channels, and seepage water. This distinguishes it from *A. stephensi*, which prefers stagnant water in urban containers. * **Option B (Vector Efficiency):** This is a correct statement. It is a highly efficient vector. Due to its high survival rate and frequent feeding habits, it can maintain malaria transmission even when its **population density is low**. * **Option C (Feeding Habit):** This is a correct statement. In most hilly regions, *A. fluviatilis* is **highly anthropophilic** (prefers human blood over animals), which contributes to its high "Vectorial Capacity." **3. High-Yield NEET-PG Pearls:** * **Primary Vector of Hilly Areas:** *Anopheles fluviatilis*. * **Primary Vector of Urban Malaria:** *Anopheles stephensi*. * **Primary Vector of Rural Malaria:** *Anopheles culicifacies* (responsible for 60-70% of cases in India). * **Primary Vector of Coastal Areas/Islands:** *Anopheles sundaicus*. * **Resting Habit:** *A. fluviatilis* is primarily **endophilic** (rests indoors), making it susceptible to Indoor Residual Spraying (IRS).

Q: Which of the following is not monitored in malaria surveillance currently?

Infant parasite rate. **Explanation:** In the current strategy of the **National Center for Vector Borne Diseases Control (NCVBDC)**, surveillance focuses on the active and passive detection of cases within the general population to monitor transmission intensity and program efficiency. **Why "Infant Parasite Rate" is the correct answer:** The **Infant Parasite Rate (IPR)** is defined as the percentage of infants (under 1 year) showing parasites in their blood. While it was historically considered the best indicator of **recent/current malaria transmission** in a locality, it is no longer used for routine monitoring under the current National Program. Modern surveillance shifted towards more comprehensive community-wide indices. **Analysis of Incorrect Options:** * **ABER (Annual Blood Examination Rate):** This monitors the **efficiency of the surveillance system**. It measures the number of slides examined per 100 population per year. A minimum ABER of 10% is generally required to ensure adequate case detection. * **API (Annual Parasite Incidence):** This is the **primary indicator** used to classify malaria endemicity in an area. It is calculated as (Total confirmed cases / Total population) × 1000. * **SPR (Slide Positivity Rate):** This measures the proportion of slides found positive among those examined. It is a sensitive indicator of the **prevalence of malaria** in a community at a given time. **High-Yield Pearls for NEET-PG:** * **API < 1** is the threshold for an area to enter the "Elimination Phase." * **Annual Falciparum Incidence (AFI)** and **Slide Falciparum Rate (SFR)** are used specifically to monitor the burden of *P. falciparum*. * **Active Surveillance:** Health workers visit houses (usually fortnightly) to detect fever cases. * **Passive Surveillance:** Cases are detected when patients voluntarily visit health facilities.

Q: Which of the following diseases are transmitted by Aedes aegypti?

Dengue. **Explanation** The correct answer is **Dengue**. *Aedes aegypti*, also known as the "tiger mosquito" due to its striped appearance, is the primary vector for Dengue fever. It is a day-biting mosquito that typically breeds in artificial collections of clean water (e.g., flower pots, discarded tires, coolers). **Analysis of Options:** * **Dengue (Correct):** Transmitted by *Aedes aegypti* and *Aedes albopictus*. It is characterized by high fever, retro-orbital pain, and "break-bone" joint pain. * **Japanese Encephalitis (Incorrect):** Transmitted primarily by **Culex** mosquitoes (specifically *Culex tritaeniorhynchus*), which breed in rice fields and stagnant water. * **Kyasanur Forest Disease (Incorrect):** This is a viral hemorrhagic fever transmitted by **Hard Ticks** (*Haemaphysalis spinigera*). It is endemic to the Western Ghats of India. * **Yellow Fever (Incorrect):** While *Aedes aegypti* **is** the vector for Yellow Fever, in the context of Indian competitive exams like NEET-PG, Dengue is the classic association because Yellow Fever is not endemic to India. (Note: If the question allows multiple correct answers, both C and D would be technically correct, but Dengue is the most clinically relevant answer in the Indian subcontinent). **High-Yield NEET-PG Pearls:** * **Aedes aegypti** also transmits: Chikungunya, Zika virus, and Rift Valley Fever. * **Bionomics:** It is a "nervous feeder" (bites multiple people to complete one meal) and has a flight range of approximately 100 meters. * **Control:** The most effective control measure is **Source Reduction** (eliminating breeding sites). The "Aedes Index" (House Index) is used to monitor the risk of outbreaks.

Q: Aedes mosquito transmits all the following diseases, EXCEPT?

West Nile fever. **Explanation:** The correct answer is **West Nile fever** because it is primarily transmitted by the **Culex** mosquito (specifically *Culex pipiens* complex), not the Aedes mosquito. ### 1. Why West Nile Fever is the Exception: West Nile Virus (WNV) is a flavivirus maintained in an **enzootic cycle** between birds (natural reservoir) and Culex mosquitoes. Humans and horses are "dead-end hosts." While Aedes species can occasionally carry the virus, they are not the primary vectors responsible for human outbreaks. ### 2. Analysis of Incorrect Options (Diseases transmitted by Aedes): * **Dengue:** Transmitted primarily by *Aedes aegypti* (principal vector) and *Aedes albopictus*. * **Chikungunya:** Caused by a Togavirus, transmitted by the same Aedes species as Dengue. * **Yellow Fever:** Transmitted by *Aedes aegypti* in urban cycles and *Haemagogus* species in jungle cycles. ### 3. High-Yield Clinical Pearls for NEET-PG: * **Aedes aegypti Characteristics:** Known as the "Tiger Mosquito" due to white stripes on its body. It is a **day-biter** (mostly early morning and late afternoon), breeds in **artificial collections of clean water** (coolers, tires, flower pots), and is a "nervous feeder" (bites multiple people to complete one meal). * **Vector for Zika:** Aedes mosquitoes also transmit the Zika virus. * **Culex vs. Aedes:** Remember the mnemonic: **C**ulex for **C**ulex-borne diseases like Japanese Encephalitis, West Nile, and Bancroftian Filariasis. * **Flight Range:** Aedes has a short flight range (usually <100 meters), making localized vector control highly effective.

Q: A 2-year duration in terms of leprosy refers to what?

Post-treatment surveillance of paucibacillary leprosy. ### Explanation In the context of the National Leprosy Eradication Programme (NLEP), the duration of **post-treatment surveillance** (follow-up) is a critical component to monitor for relapse or late reactions. **1. Why Option C is Correct:** According to NLEP guidelines, once a patient completes the Multi-Drug Therapy (MDT) regimen, they enter a surveillance phase. For **Paucibacillary (PB) leprosy**, the surveillance period is **2 years**. During this time, patients are monitored to ensure there is no clinical recurrence of the disease. **2. Analysis of Incorrect Options:** * **Option A:** The treatment duration for PB leprosy is **6 months** (to be completed within a maximum of 9 months). * **Option B:** The treatment duration for Multibacillary (MB) leprosy is **12 months** (to be completed within a maximum of 18 months). * **Option D:** The post-treatment surveillance period for **MB leprosy** is **5 years**, reflecting the higher bacterial load and increased risk of late relapse compared to PB cases. **3. High-Yield Clinical Pearls for NEET-PG:** * **Classification:** PB leprosy involves 1–5 lesions and no nerve involvement (or only one nerve); MB leprosy involves >5 lesions or ≥2 nerve involvements. * **MDT Regimen (Adult MB):** Rifampicin (600mg monthly), Dapsone (100mg daily), and Clofazimine (300mg monthly + 50mg daily). * **MDT Regimen (Adult PB):** Rifampicin (600mg monthly) and Dapsone (100mg daily). * **Accompanied MDT:** A strategy where the full course of MDT is provided to the patient at the start to ensure treatment completion in difficult-to-reach areas. * **Release from Treatment (RFT):** A patient is "released from treatment" after completing the pulses, regardless of the persistence of skin patches, as these often take time to fade.

Q: All of the following diseases are transmitted by mosquito vectors except?

Babesiosis. **Explanation:** The correct answer is **Babesiosis** because it is a tick-borne zoonosis, not a mosquito-borne disease. **1. Why Babesiosis is the correct answer:** Babesiosis is caused by intraerythrocytic protozoa of the genus *Babesia*. It is primarily transmitted by the bite of **Ixodes ticks** (hard ticks), the same vector responsible for Lyme disease. It is clinically significant as it can mimic malaria due to the destruction of red blood cells, leading to hemolytic anemia and jaundice. **2. Analysis of Incorrect Options (Mosquito-borne diseases):** * **West Nile Fever:** Transmitted by the **Culex** mosquito. It is a viral zoonosis that can lead to fatal neurological diseases in humans. * **Brugian Filariasis:** Caused by *Brugia malayi* or *B. timori*. The primary vectors are mosquitoes of the **Mansonia** and **Anopheles** genera. * **Rift Valley Fever (RVF):** A viral zoonosis primarily transmitted by **Aedes** and **Culex** mosquitoes. Outbreaks are often associated with heavy rainfall and flooding. **High-Yield Clinical Pearls for NEET-PG:** * **Vector Identification:** Always remember the "Big Three" for Ixodes ticks: **Lyme disease, Babesiosis, and Human Granulocytic Anaplasmosis.** * **Maltese Cross Appearance:** On a peripheral blood smear, *Babesia* parasites often form a tetrad structure known as a "Maltese Cross," which is pathognomonic and distinguishes it from *Plasmodium falciparum*. * **Mansonia Mosquito:** Specifically associated with **Brugian Filariasis** and is unique because its larvae attach to the roots of aquatic plants (e.g., *Pistia*) for respiration.

Q: The "EYE" strategy is developed for the elimination of which disease?

Yellow fever. **Explanation:** The **EYE strategy** stands for **"Eliminate Yellow Fever Epidemics."** It is a comprehensive global strategy launched in 2017 by the WHO, UNICEF, and Gavi, the Vaccine Alliance. The initiative was developed in response to the resurgence of Yellow Fever and aims to protect nearly 1 billion people in 40 high-risk countries (mainly in Africa and the Americas) by 2026. **The strategy relies on three strategic pillars:** 1. Protecting at-risk populations through vaccination. 2. Preventing international spread. 3. Containing outbreaks rapidly. **Analysis of Incorrect Options:** * **A. Yaws:** The global strategy for Yaws is the **"Morges Strategy,"** which focuses on eradication using oral Azithromycin. * **C. Leptospirosis:** There is no specific "EYE" strategy for Leptospirosis; control focuses on rodent control and sanitation. * **D. Zika virus:** While Zika is a flavivirus like Yellow Fever, its control falls under the **"Zika Strategic Response Framework,"** focusing on vector control and pregnancy monitoring. **High-Yield NEET-PG Pearls:** * **Yellow Fever Vaccine:** The **17D strain** is a live-attenuated vaccine. It provides lifelong immunity (as per WHO International Health Regulations since 2016). * **Validity:** The International Certificate of Vaccination becomes valid **10 days** after vaccination. * **Vector:** Primarily *Aedes aegypti* (Urban cycle) and *Haemagogus* species (Sylvan/Jungle cycle). * **India Status:** India is "Yellow Fever free" but remains receptive due to the presence of the *Aedes* vector. Strict quarantine rules apply to travelers from endemic zones.

Question 1

Which of the following statements regarding Anopheles Fluviatilis is INCORRECT?

Accepted Answer

It is restricted to the Andaman and Nicobar Islands.

Answer

It breeds in moving water.

Answer

It propagates malaria at lower densities compared to other Anopheles species.

Answer

It is highly anthropophilic.

Question 2

Which of the following is not monitored in malaria surveillance currently?

Accepted Answer

Infant parasite rate

Answer

ABER

Answer

Annual parasite incidence

Answer

Slide positivity rate

Question 3

Which of the following diseases are transmitted by Aedes aegypti?

Accepted Answer

Dengue

Answer

Japanese Encephalitis

Answer

Kyasanur Forest Disease

Answer

Yellow Fever

Question 4

A sexually active woman presents with vaginal discharge. According to the syndromic approach for management, which of the following drug regimens should be prescribed?

Accepted Answer

Metronidazole, Azithromycin, Fluconazole

Answer

Metronidazole

Answer

Azithromycin

Answer

Metronidazole and Fluconazole

Question 5

In Salmonellosis disease, until when is isolation recommended?

Accepted Answer

Until stool culture is negative for three consecutive times

Answer

Until fever subsides

Answer

Until blood culture is negative

Answer

Until spleen size returns to normal

Question 6

Aedes mosquito transmits all the following diseases, EXCEPT?

Accepted Answer

West Nile fever

Answer

Dengue

Answer

Chikungunya

Answer

Yellow fever

Question 7

Which of the following statements regarding leprosy is false?

Accepted Answer

A defaulter is defined as a patient who has not collected treatment for 6 months.

Answer

Multibacillary leprosy is defined as a patient having more than 5 skin lesions.

Answer

The target for elimination of leprosy is a prevalence rate below 1 per 10,000 population.

Answer

Annual New Case Detection Rate (ANCDR) is a measure of the incidence of leprosy.

Question 8

A 2-year duration in terms of leprosy refers to what?

Accepted Answer

Post-treatment surveillance of paucibacillary leprosy

Answer

Treatment of paucibacillary leprosy

Answer

Treatment of multibacillary leprosy

Answer

Post-treatment surveillance of multibacillary leprosy

Question 9

All of the following diseases are transmitted by mosquito vectors except?

Accepted Answer

Babesiosis

Answer

West Nile fever

Answer

Brugian filariasis

Answer

Rift Valley fever

Question 10

The "EYE" strategy is developed for the elimination of which disease?

Accepted Answer

Yellow fever

Answer

Yaws

Answer

Leptospirosis

Answer

Zika virus

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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