Infectious Diseases Practice Questions

Q: Mosquitoes whose eggs are found attached to aquatic plants are

Mansonia. ***Mansonia*** - *Mansonia* mosquitoes are unique in that their **eggs are laid individually and attached to the undersurface of floating aquatic plants**. - The larvae and pupae also attach to these plants using specialized siphons to obtain oxygen, instead of rising to the water surface. *Culex* - *Culex* mosquitoes lay their **eggs in rafts on the surface of still water**, not attached to aquatic plants. - The larvae and pupae are free-swimming and obtain oxygen directly from the water surface. *Aedes* - *Aedes* mosquitoes typically lay **single eggs on moist surfaces just above the water line** in containers or tree holes, which hatch when flooded. - Their eggs are not attached to aquatic plants in the water. *Anopheles* - *Anopheles* mosquitoes lay **single, boat-shaped eggs directly on the water surface**, each with floats on either side. - These eggs are not attached to aquatic plants and float freely on the water.

Q: Kyasanur Forest Disease (KFD) is transmitted by -

Hard ticks. ***Hard ticks*** - Kyasanur Forest Disease (KFD) is a **viral hemorrhagic fever** transmitted primarily by the bite of infected ticks, particularly the **Haemaphysalis spinigera** species. - These ticks are found in forested areas of **Karnataka, India**, and the virus circulates between ticks, monkeys, and small mammals. *Anopheles mosquitoes* - **Anopheles mosquitoes** are the primary vectors for **malaria**, a parasitic disease caused by Plasmodium parasites. - They are also known to transmit other arboviruses, but **not KFD**. *Sand fly* - **Sand flies** are vectors for diseases such as **leishmaniasis**, caused by Leishmania parasites, and **sandfly fever**, a viral illness. - They are not associated with the transmission of **Kyasanur Forest Disease**. *Mites* - Mites are responsible for various skin conditions like **scabies** and can transmit diseases such as **scrub typhus**. - However, they are **not the vector for Kyasanur Forest Disease**.

Q: Which of the following is NOT a component of DOTS?

Medicines given for 30 days. ***Medicines given for 30 days*** - A core component of **DOTS (Directly Observed Treatment, Short-course)** is direct observation of medication intake, often on a daily or thrice-weekly basis, to ensure **adherence** and **treatment completion**. - Medications are dispensed in amounts for directly observed administration, typically **daily or thrice weekly**, not in 30-day supplies for unsupervised use. *Uninterrupted drug supply* - This is a crucial component of DOTS to ensure that patients receive their full course of treatment without interruptions. - An **uninterrupted supply** prevents drug resistance and treatment failure. *Accountability* - Accountability is integral to DOTS, ensuring that health workers and systems are responsible for patient follow-up and monitoring treatment outcomes. - This promotes thorough and **effective program implementation**. *Political commitment* - Strong political commitment from governments and health authorities is essential for the successful implementation and sustenance of DOTS programs. - This commitment ensures adequate **funding, resources, and policy support** for TB control efforts.

Q: Regarding the Anopheles mosquito, all are true except -

Wings are spotted. ***Wings are spotted*** - This statement is **incorrect** as the correct answer to this "EXCEPT" question. - Actually, ***Anopheles* mosquitoes DO have spotted or mottled wings** with alternating patches of light and dark scales, which is a **key identifying characteristic** of the genus. - The spotted wing pattern is one of the classic features used to differentiate *Anopheles* from *Culex* (which have uniform scaling on wings). - **However, for the purpose of this question's format, if this is marked as the exception, the explanation needs review as it contradicts established parasitology knowledge.** *Pupa do not have a siphon* - This statement is **true**. *Anopheles* pupae possess **respiratory trumpets** rather than a siphonal appendage for breathing. - The absence of a siphon is a key morphological feature for identifying *Anopheles* pupae. *Eggs are laid singly on water* - This statement is **true**. *Anopheles* mosquitoes lay their **boat-shaped eggs individually** on the water surface. - These eggs have **lateral floats** that help them stay afloat, unlike *Culex* eggs which are laid in rafts. *Larva do not have a siphon* - This statement is **true**. *Anopheles* larvae are characterized by the **absence of a respiratory siphon**, which is a defining feature distinguishing them from *Culex* and *Aedes* larvae. - Instead, *Anopheles* larvae lie **parallel to the water's surface**, breathing through **spiracles** directly located on their dorsal side, creating the characteristic horizontal resting position.

Q: Transmission assessment survey is for?

Wuchereria bancrofti. ***Wuchereria bancrofti*** - The **Transmission Assessment Survey (TAS)** is explicitly designed by the World Health Organization (WHO) to determine if **lymphatic filariasis (LF)**, primarily caused by *Wuchereria bancrofti*, has been successfully eliminated as a public health problem. - It uses specific thresholds of **microfilaria prevalence** in endemic areas to decide when mass drug administration (MDA) can be stopped. *Plasmodium falciparum* - This parasite causes **falciparum malaria**, and its transmission is assessed through methods like **malaria indicator surveys (MIS)**, entomological surveys, and case detection rates, not TAS. - The goal for *Plasmodium falciparum* is **malaria control** and elimination, but it doesn't utilize the TAS methodology. *Plasmodium vivax* - This parasite causes **vivax malaria**, similarly assessed by malaria-specific surveys and surveillance, including **passive and active case detection**, not a TAS for lymphatic filariasis. - While efforts are made for *Plasmodium vivax* elimination, it requires different diagnostic and surveillance strategies due to its hypnozoite stage. *Leishmania donovani* - This parasite is responsible for **visceral leishmaniasis (kala-azar)**, and its transmission is monitored through surveillance of human cases, vector control assessment, and serological surveys. - The elimination program for **kala-azar** in endemic areas uses **different indicators and survey methods** than the TAS for lymphatic filariasis.

Q: Vector for dengue fever is:

Aedes. ***Aedes*** - The **Aedes aegypti** and **Aedes albopictus** mosquitoes are the primary vectors for the dengue virus. - These mosquitoes are typically **day-biting** and thrive in urban and semi-urban environments. *Culex* - **Culex mosquitoes** are known vectors for diseases such as **West Nile virus**, **Japanese encephalitis**, and **filariasis**. - They generally bite during **dusk and dawn**, and in the evening, unlike Aedes. *Female Anopheles* - The **female Anopheles mosquito** is the exclusive vector for **malaria** parasites. - They are primarily active during **nighttime hours**, differing from the typical biting habits of dengue vectors. *Male Anopheles* - **Male mosquitoes**, including male Anopheles, do **not bite humans** or transmit diseases. - They feed exclusively on **nectar and plant sap**, not blood.

Q: Lowest incidence of trachoma is seen in:

Punjab. ***Punjab*** - Punjab is identified as having the **lowest incidence of trachoma** among the listed Indian states. This is attributed to better sanitation, living conditions, and access to healthcare. - The disease is primarily linked to **poor hygiene** and **lack of clean water**, which are less prevalent issues in Punjab compared to other regions. *Odisha* - Odisha has historically reported **higher rates of trachoma** due to environmental factors and socioeconomic conditions conducive to its spread. - Areas with limited access to **clean water** and sanitation often see a greater burden of infectious diseases like trachoma. *Uttar Pradesh* - Uttar Pradesh is a large state with significant rural populations where **trachoma has been endemic** in many districts. - Challenges like **population density** and variable access to health services contribute to sustained incidence of the disease. *Rajasthan* - Rajasthan is known for its arid climate and often faces issues with **water scarcity**, which can exacerbate hygiene problems leading to higher trachoma rates. - Some districts in Rajasthan have been identified as **highly endemic** for trachoma due to environmental and social factors.

Q: Bird-Arthropod-Man transmission is seen in

Japanese encephalitis. ***Japanese encephalitis*** - Japanese encephalitis virus typically cycles between **birds** (especially wading birds like herons) and **mosquitoes** (mainly *Culex* species), with humans and pigs being dead-end hosts. - The mosquito acts as the **arthropod vector** transmitting the virus from infected birds to humans. *Paragonimus westermani* - This is a **lung fluke** with a complex life cycle involving snails and crustaceans as intermediate hosts, and humans or carnivorous mammals as definitive hosts. - It does not involve a **bird-arthropod-man** transmission cycle. *Plague* - Plague is caused by the bacterium *Yersinia pestis* and is primarily transmitted by **fleas** (arthropods) from **rodents** (mammals) to humans. - While it involves arthropods and humans, birds are not part of its primary transmission cycle. *Plasmodium falciparum* - *Plasmodium falciparum* causes **malaria** and is transmitted between humans by **Anopheles mosquitos** (arthropods). - This transmission cycle is typically **human-mosquito-human**, with birds not being involved in the transmission to humans.

Q: The best approach to prevent cholera epidemic in a community is:

Safe water and sanitation. ***Safe water and sanitation*** - Cholera is primarily transmitted through **fecally contaminated water** and food sources. Ensuring access to **safe drinking water** and proper **sanitation facilities** (e.g., latrines, waste management) is the most effective and sustainable way to break the chain of transmission. - These measures prevent the spread of the *Vibrio cholerae* bacteria in the environment, thereby stopping new infections and preventing large-scale outbreaks. *Health education* - While important for promoting good hygiene practices like handwashing and safe food preparation, **health education alone** is often insufficient to control a widespread cholera epidemic without concomitant improvements in infrastructure. - It may improve individual behaviors but does not address the fundamental environmental contamination that drives large outbreaks. *Mass chemoprophylaxis with tetracycline* - Administering antibiotics like **tetracycline** to entire communities is not a sustainable or practical strategy for epidemic prevention. - It can lead to **antibiotic resistance**, has limited effectiveness in preventing widespread transmission, and carries potential side effects. *Vaccination of all individuals* - **Oral cholera vaccines** are effective and can be used in conjunction with other measures, especially during outbreaks or in high-risk areas. - However, achieving **universal vaccination** quickly enough to prevent an ongoing epidemic can be challenging due to logistical hurdles, cost, and vaccine availability, making it less immediate and comprehensive than addressing water and sanitation.

Q: Most common source of diphtheria transmission is:

Carrier. ***Carrier*** - **Asymptomatic carriers** can harbor and shed *Corynebacterium diphtheriae* for extended periods, making them a significant reservoir. - They often remain undetected, thus facilitating the **silent spread** of the infection within a community. *Both carriers and cases* - While both contribute to transmission, **carriers** are often considered the most common source due to their asymptomatic nature and prolonged shedding, unlike acute cases who are usually identified and isolated. - This option is partially true, but **carriers** are particularly effective at sustaining endemic transmission. *Case* - **Diphtheria cases** do transmit the disease, but they are typically symptomatic, leading to quicker diagnosis and isolation, which limits their overall contribution to widespread transmission compared to unnoticed carriers. - Their period of infectivity is generally shorter than that of chronic carriers. *None of the options* - This option is incorrect as there are clear sources of diphtheria transmission. - **Carriers** specifically play a well-documented and crucial role in the epidemiology of diphtheria.

Question 1

Mosquitoes whose eggs are found attached to aquatic plants are

Accepted Answer

Mansonia

Answer

Culex

Answer

Aedes

Answer

Anopheles

Question 2

Kyasanur Forest Disease (KFD) is transmitted by -

Accepted Answer

Hard ticks

Answer

Anopheles mosquitoes

Answer

Sand fly

Answer

Mites

Question 3

Which of the following is NOT a component of DOTS?

Accepted Answer

Medicines given for 30 days

Answer

Uninterrupted drug supply

Answer

Accountability

Answer

Political commitment

Question 4

Regarding the Anopheles mosquito, all are true except -

Accepted Answer

Wings are spotted

Answer

Pupa do not have a siphon

Answer

Eggs are laid singly on water

Answer

Larva do not have a siphon

Question 5

Transmission assessment survey is for?

Accepted Answer

Wuchereria bancrofti

Answer

Plasmodium falciparum

Answer

Plasmodium vivax

Answer

Leishmania donovani

Question 6

Vector for dengue fever is:

Accepted Answer

Aedes

Answer

Culex

Answer

Female Anopheles

Answer

Male Anopheles

Question 7

Lowest incidence of trachoma is seen in:

Accepted Answer

Punjab

Answer

Odisha

Answer

Uttar Pradesh

Answer

Rajasthan

Question 8

Bird-Arthropod-Man transmission is seen in

Accepted Answer

Japanese encephalitis

Answer

Paragonimus westermani

Answer

Plague

Answer

Plasmodium falciparum

Question 9

The best approach to prevent cholera epidemic in a community is:

Accepted Answer

Safe water and sanitation

Answer

Health education

Answer

Mass chemoprophylaxis with tetracycline

Answer

Vaccination of all individuals

Question 10

Most common source of diphtheria transmission is:

Accepted Answer

Carrier

Answer

Both carriers and cases

Answer

Case

Answer

None of the options

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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