NEET-PG 2015 - Community Medicine Practice Questions

Q: Which of the following is an example of indirect transmission by a living vector?

Transmission by mosquito. ***Transmission by mosquito*** - This is the classic example of **vector-borne transmission**, where a living biological vector (the mosquito) acts as an intermediary to transmit the infectious agent from an infected host to a susceptible one. - The disease-causing microorganism does not pass directly from person to person but is carried and transmitted by the living vector. - Examples include malaria, dengue, and filariasis. *Vertical transmission* - This refers to transmission of disease from a **mother to her child** during pregnancy, childbirth, or breastfeeding. - This is a form of **direct transmission** where the pathogen passes directly between biologically related individuals without an intermediate living vector. *Soil contact* - This represents **vehicle-borne transmission** where soil acts as a non-living vehicle (fomite) carrying pathogens. - While this is technically indirect transmission, it does not involve a **living biological vector** as specified in the question. - Examples include tetanus, hookworm, and ascariasis transmitted through contaminated soil. *Droplet infection* - This is a form of **direct transmission** where infectious droplets are expelled from the respiratory tract of an infected person and directly contact the mucous membranes of a susceptible person. - The droplets travel a short distance in close proximity, representing direct person-to-person transfer without any intermediate vector.

Q: Droplet nuclei is a type of ?

Indirect transmission of pathogens. ***Indirect transmission of pathogens*** - **Droplet nuclei** are tiny airborne particles remaining after the evaporation of respiratory droplets, suspended in the air for prolonged periods, allowing pathogens to travel over longer distances. - This mode of transmission is considered **indirect** because it involves an environmental medium (air) rather than direct contact between individuals. *Vertical transmission of pathogens* - This refers to the transmission of a pathogen from a **mother to her offspring**, either during pregnancy, childbirth, or breastfeeding. - Examples include HIV and rubella, which are transmitted directly from parent to child, unlike airborne droplet nuclei. *Direct transmission of infectious agents* - This involves immediate physical contact or exposure between an infected individual and a susceptible host (e.g., touching, kissing, sexual contact). - It does not involve an intermediate environmental vehicle such as airborne particles that travel through the air from their source. *Biological transmission of pathogens* - This type of transmission involves an **arthropod vector** that not only transmits the pathogen but also allows it to multiply or develop within its body before transmission. - Examples include malaria transmitted by mosquitoes or Lyme disease by ticks, which is distinct from airborne droplet nuclei transmission.

Q: Human, animal, fomite or objects from which infective organism enters the host is called?

Source of infection. ***Source of infection*** - The **source of infection** refers to the person, animal, object, or substance from which an infectious agent passes immediately to a host. - This can include humans, animals, fomites, or contaminated objects that directly transmit the infectious organism. - This is the proximate source from which the agent enters the host. *Infective Reservoir* - An **infective reservoir** is the long-term habitat where an infectious agent normally lives, grows, and multiplies. - The reservoir can be human, animal, plant, soil, or inanimate matter where the agent is normally found. - While a reservoir can be a source, the source is specifically the immediate point from which transmission occurs. *Infective Carrier* - An **infective carrier** is an infected person or animal that harbors a specific infectious agent without showing clinical symptoms but can transmit it to others. - A carrier is a type of source (when transmission occurs from them), but the term "source" is broader, encompassing inanimate objects and fomites as well. *None of the above* - This option is incorrect because **Source of infection** accurately describes the concept presented in the question.

Q: Drug of choice for mass therapy under filariasis control programme?

DEC. ***Correct: DEC*** - **Diethylcarbamazine (DEC)** is the drug of choice for **mass drug administration (MDA)** campaigns aimed at eliminating lymphatic filariasis. - It effectively kills **microfilariae** and has some action on adult worms, reducing transmission. - In India's National Filariasis Elimination Programme, DEC is administered along with Albendazole in annual MDA campaigns. *Incorrect: Albendazole* - While **Albendazole** is co-administered with DEC in MDA programs, it is not the sole drug of choice for mass treatment of filariasis. - Its primary role is to provide **macrofilaricidal** activity (killing adult worms) and co-treatment for other helminth infections. - It enhances the effect of DEC but is not used alone. *Incorrect: Ivermectin* - **Ivermectin** is used in MDA programs for filariasis, particularly in areas co-endemic with **onchocerciasis** or where **Loa loa** is prevalent (as DEC is contraindicated in these areas). - However, in India and most lymphatic filariasis endemic areas, **DEC** remains the primary drug. *Incorrect: Mebendazole* - **Mebendazole** is an anthelminthic primarily used for treating **intestinal nematode infections** like ascariasis, trichuriasis, and hookworm. - It is **not used** in lymphatic filariasis mass treatment programs.

Q: Which of the following larvicide is used under urban Malaria Scheme?

Abate. ***Abate*** - **Abate (temephos)** is an organophosphate larvicide widely used in public health programs, including the urban malaria scheme, due to its effectiveness against mosquito larvae at low concentrations. - It is applied to water storage containers, wells, and other mosquito breeding sites to **prevent the development of adult mosquitoes**. *Malathion* - **Malathion** is an organophosphate insecticide primarily used as an **adulticide** for fogging operations against adult mosquitoes, not specifically as a larvicide in urban schemes. - While it can kill larvae, its primary application and efficacy are geared towards **adult mosquito control**. *Parathion* - **Parathion** is a highly toxic organophosphate insecticide that is generally **not used in public health programs** due to its significant environmental and human health risks. - Its use is largely restricted to agricultural pest control and is **not a recommended larvicide** for urban settings. *DDT* - **DDT (dichlorodiphenyltrichloroethane)** is a persistent organic pollutant whose use has been largely banned or severely restricted globally due to its **environmental impact** and long-term toxicity. - While historically used for mosquito control (both larvae and adults), it is **not used in current urban malaria schemes** due to its banned status in many regions and resistance issues.

Q: In the context of malaria control, when is regular insecticidal spray recommended based on the Annual Parasite Index (API)?

> 2. ***> 2*** - Regular insecticidal spray, particularly **Indoor Residual Spraying (IRS)**, is a key malaria control measure recommended when the **Annual Parasite Index (API) is greater than 2**. - An API greater than 2 indicates **high endemicity** with a significant burden of malaria transmission in the community, necessitating aggressive vector control strategies. - According to **NVBDCP (National Vector Borne Disease Control Programme) guidelines**, API > 2 defines high-risk areas where routine IRS is implemented as a core intervention. *> 1* - An API between 1-2 represents **moderate endemicity**, where the focus is primarily on **active case detection, prompt treatment, and targeted interventions** rather than universal spraying. - While vector control remains important, routine widespread IRS is not the standard recommendation at this threshold. *< 2* - An API of less than 2 (which includes both moderate and low endemic areas) does not routinely warrant universal insecticidal spraying programs. - In areas with API < 2, **case management, surveillance, and selective vector control** are prioritized over widespread IRS campaigns. *< 1* - An API of less than 1 indicates **low endemicity**, where malaria transmission is minimal and sporadic. - In such areas, **surveillance, prompt case detection and treatment, and targeted interventions** are the mainstay, with IRS reserved only for focal outbreaks or high-risk pockets.

Q: Which condition has the maximum relative risk attributed to obesity?

DM. ***DM*** - Obesity is a major risk factor for Type 2 Diabetes Mellitus (T2DM), with a **relative risk often exceeding 3-7 times that of normal-weight individuals**, and even higher for severe obesity. - The link is primarily due to **insulin resistance** caused by increased adipose tissue. *Hypertension* - Obesity significantly increases the risk of hypertension, with a relative risk typically in the range of **2 to 3 times higher** than normal-weight individuals. - The mechanisms involve increased **blood volume**, **sympathetic nervous system activity**, and **renal sodium reabsorption**. *CHD* - Obesity is a strong independent risk factor for Coronary Heart Disease (CHD), contributing to a relative risk of approximately **1.5 to 2.5 times higher** than normal weight. - It often acts by exacerbating other risk factors like **hypertension**, **dyslipidemia**, and **diabetes**. *Cancer* - Obesity is linked to various cancers, including endometrial, esophageal adenocarcinoma, renal cell, and breast cancer in postmenopausal women, with relative risks typically ranging from **1.2 to 2 times higher** for specific cancers. - The pathways include **chronic inflammation**, altered **hormone levels** (e.g., estrogen), and **insulin-like growth factor signaling**.

Q: Which of the following vaccines is not freeze-dried?

Diphtheria, Pertussis, and Tetanus (DPT) Vaccine. ***Diphtheria, Pertussis, and Tetanus (DPT) Vaccine*** - The DPT vaccine is a **liquid vaccine** that contains inactivated toxins and bacterial components, making it stable in liquid form. - It does not require **freeze-drying** because its components are chemically stable and do not degrade significantly in solution. *Measles Vaccine* - The measles vaccine is a **live attenuated vaccine** that needs to be freeze-dried to maintain the viability and stability of the live virus. - Freeze-drying helps preserve the vaccine's potency by removing water, which prevents degradation during storage and transport. *Rubella Vaccine* - Similar to the measles vaccine, the rubella vaccine is a **live attenuated vaccine** and is therefore provided in a freeze-dried form. - This process ensures the long-term stability and efficacy of the viral components, which would otherwise degrade in a liquid state. *BCG Vaccine* - The BCG (Bacillus Calmette-Guérin) vaccine is a **live attenuated bacterial vaccine** used against tuberculosis, and it is also manufactured as a freeze-dried product. - Freeze-drying is essential for maintaining the viability of the live attenuated *Mycobacterium bovis* strain.

Q: Which vaccine is the most widely used globally in childhood vaccination programs, aside from the Oral Polio Vaccine (OPV)?

DPT vaccine. ***DPT vaccine*** - The **DPT (diphtheria, pertussis, and tetanus) vaccine** is the most widely used childhood vaccine globally after OPV, forming the backbone of the **WHO's Expanded Programme on Immunization (EPI)**. - It has **near-universal adoption** across countries worldwide with approximately **86% global coverage** and is administered as a **3-dose primary series** to all children, making it the standard benchmark for measuring immunization program performance. - Its widespread use reflects the global burden of these three bacterial diseases and the vaccine's proven efficacy in preventing severe outcomes and transmission. *BCG vaccine* - The **BCG (Bacillus Calmette-Guérin) vaccine** protects against **tuberculosis** and is widely used, particularly in countries with high TB prevalence. - However, its use is **not universal** – many countries with low TB incidence (such as the USA and several European nations) do not include BCG in routine childhood schedules, limiting its global "universality" compared to DPT. - BCG is typically given as a **single dose at birth**, whereas DPT requires multiple doses throughout infancy. *Influenza vaccine* - The **influenza vaccine** is recommended annually due to antigenic drift of the virus, but its global childhood vaccination coverage is significantly lower compared to standard EPI vaccines like DPT. - It is often prioritized for specific risk groups rather than universal immunization for all children in many parts of the world. *Pneumococcal vaccine* - The **pneumococcal vaccine** targets **Streptococcus pneumoniae**, a cause of pneumonia, meningitis, and other severe diseases. - While increasingly integrated into national immunization schedules, its global adoption (especially as of 2015) was still lower than DPT, with many low- and middle-income countries only recently introducing it.

Question 1

Which of the following is an example of indirect transmission by a living vector?

Accepted Answer

Transmission by mosquito

Answer

Vertical transmission

Answer

Soil contact

Answer

Droplet infection

Question 2

Droplet nuclei is a type of ?

Accepted Answer

Indirect transmission of pathogens

Answer

Direct transmission of infectious agents

Answer

Vertical transmission of pathogens

Answer

Biological transmission of pathogens

Question 3

Human, animal, fomite or objects from which infective organism enters the host is called?

Accepted Answer

Source of infection

Answer

Infective Reservoir

Answer

Infective Carrier

Answer

None of the above

Question 4

What is the definition of a reservoir in the context of infectious diseases?

Accepted Answer

Person, animal or substance in which infectious agent lives and multiplies

Answer

Person, animal or object from which infectious agent is transmitted to host

Answer

Person or animal in which infectious agent causes a disease

Answer

Person or animal that transmits the infectious agent mechanically

Question 5

Drug of choice for mass therapy under filariasis control programme?

Accepted Answer

DEC

Answer

Albendazole

Answer

Ivermectin

Answer

Mebendazole

Question 6

Which of the following larvicide is used under urban Malaria Scheme?

Accepted Answer

Abate

Answer

Malathion

Answer

Parathion

Answer

DDT

Question 7

In the context of malaria control, when is regular insecticidal spray recommended based on the Annual Parasite Index (API)?

Accepted Answer

> 2

Answer

< 1

Answer

< 2

Answer

> 1

Question 8

Which condition has the maximum relative risk attributed to obesity?

Accepted Answer

DM

Answer

Hypertension

Answer

CHD

Answer

Cancer

Question 9

Which of the following vaccines is not freeze-dried?

Accepted Answer

Diphtheria, Pertussis, and Tetanus (DPT) Vaccine

Answer

Measles Vaccine

Answer

Rubella Vaccine

Answer

BCG Vaccine

Question 10

Which vaccine is the most widely used globally in childhood vaccination programs, aside from the Oral Polio Vaccine (OPV)?

Accepted Answer

DPT vaccine

Answer

BCG vaccine

Answer

Influenza vaccine

Answer

Pneumococcal vaccine

NEET-PG 2015 — Community Medicine