Infectious Diseases Practice Questions

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.

Q: Under National Vector Borne Diseases Control Programme, operational efficiency of antimalarial measures is assessed by:

Annual Parasite Incidence. ***Annual Parasite Incidence*** - **Annual Parasite Incidence (API)** is a key indicator for assessing the operational efficiency of malaria control measures as it measures the **number of confirmed malaria cases per 1,000 population per year**. - A decrease in API over time suggests that antimalarial measures are effectively reducing the incidence of malaria in the population. *Infant parasite rate* - The **infant parasite rate** specifically focuses on malaria infection prevalence in infants, often reflecting recent transmission. - While important for understanding ongoing transmission, it may not reflect the overall operational efficiency of all antimalarial measures across all age groups. *Slide positivity rate* - The **slide positivity rate (SPR)** indicates the proportion of blood smears examined that are positive for malaria parasites. - SPR reflects the intensity of transmission and diagnostic efficiency, but a high SPR could also indicate poor case detection or treatment, making it less direct for assessing operational efficiency of control over a population. *Annual Blood Examination Rate* - The **Annual Blood Examination Rate (ABER)** indicates the proportion of the population whose blood is examined for malaria parasites within a year. - ABER reflects surveillance efforts and case detection, but a high ABER without a corresponding decrease in malaria cases does not necessarily signify efficient control measures for reducing disease burden.

Question 1

Kyasanur Forest Disease (KFD) is transmitted by -

Accepted Answer

Hard ticks

Answer

Anopheles mosquitoes

Answer

Sand fly

Answer

Mites

Question 2

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 3

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 4

Transmission assessment survey is for?

Accepted Answer

Wuchereria bancrofti

Answer

Plasmodium falciparum

Answer

Plasmodium vivax

Answer

Leishmania donovani

Question 5

Vector for dengue fever is:

Accepted Answer

Aedes

Answer

Culex

Answer

Female Anopheles

Answer

Male Anopheles

Question 6

Lowest incidence of trachoma is seen in:

Accepted Answer

Punjab

Answer

Odisha

Answer

Uttar Pradesh

Answer

Rajasthan

Question 7

Bird-Arthropod-Man transmission is seen in

Accepted Answer

Japanese encephalitis

Answer

Paragonimus westermani

Answer

Plague

Answer

Plasmodium falciparum

Question 8

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 9

Most common source of diphtheria transmission is:

Accepted Answer

Carrier

Answer

Both carriers and cases

Answer

Case

Answer

None of the options

Question 10

Under National Vector Borne Diseases Control Programme, operational efficiency of antimalarial measures is assessed by:

Accepted Answer

Annual Parasite Incidence

Answer

Infant parasite rate

Answer

Slide positivity rate

Answer

Annual Blood Examination Rate

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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