Which is the main vector of Dengue?
Which of the following is a zoonotic disease?
Which of the following statements about the Late Expanding Phase of the Demographic Cycle is TRUE?
What does the net reproduction rate indicate?
Which agency monitors air quality in India?
In which of the following diseases is mass vaccination considered ineffective?
Secondary prevention is applicable to
Which method is primarily used to assess HIV prevalence?
What is the most common cancer diagnosed in men?
Which disease is associated with a propagative cycle?
NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs
Question 21: Which is the main vector of Dengue?
- A. A. aegypti (Correct Answer)
- B. Culex
- C. Anopheles
- D. Aedes scutellaris
Explanation: ***A. aegypti*** - **Aedes aegypti** is the primary vector responsible for transmitting the **Dengue virus** to humans. - It is a **day-biting mosquito** found predominantly in tropical and subtropical regions. *Culex* - **Culex mosquitoes** are known vectors for diseases like **Japanese encephalitis**, **West Nile virus**, and **filariasis**. - They are generally **night-biting** and do not play a significant role in Dengue transmission. *Anopheles* - **Anopheles mosquitoes** are the primary vectors for **malaria** in humans. - They are not associated with the transmission of the Dengue virus. *Aedes scutellaris* - While part of the **Aedes genus**, **Aedes scutellaris** is a secondary vector for Dengue in the **Pacific region**. - The main vector for Dengue globally remains **Aedes aegypti**, followed by **Aedes albopictus** in some regions.
Question 22: Which of the following is a zoonotic disease?
- A. Hydatid cyst (Correct Answer)
- B. Malaria
- C. Filariasis
- D. Dengue fever
Explanation: ***Hydatid cyst*** - This disease is caused by the larval stage of the tapeworm **Echinococcus granulosus**, which completes its life cycle in dogs and sheep. - Humans can become infected by ingesting material contaminated with **Echinococcus eggs**, typically from contact with infected dogs or contaminated food/water, making it a zoonotic disease. *Malaria* - Malaria is transmitted by the **Anopheles mosquito** biting infected humans and then uninfected humans. - While it involves a vector, its primary reservoir is humans and it is not typically considered zoonotic as there is no animal-to-human transmission from a non-human primary reservoir. *Filariasis* - Filariasis is spread by various mosquito vectors (e.g., **Culex, Anopheles, Aedes**) that transmit parasitic worms to humans. - The life cycle primarily involves humans and mosquitos, and it is not classified as a zoonotic disease. *Dengue fever* - Dengue fever is a viral infection transmitted by **Aedes mosquitoes** (primarily *Aedes aegypti* and *Aedes albopictus*) between humans. - Similar to malaria, while it involves a vector, the primary reservoir is humans, and it is not considered zoonotic.
Question 23: Which of the following statements about the Late Expanding Phase of the Demographic Cycle is TRUE?
- A. Death Rate becomes significantly lower than Birth Rate during this phase
- B. Death Rate declines more than Birth Rate (Correct Answer)
- C. Birth Rate remains consistently high while Death Rate starts to decline significantly
- D. Birth Rate remains higher than Death Rate, leading to population growth
Explanation: ***Death Rate declines more than Birth Rate*** - In the **Late Expanding Phase**, the **birth rate** remains high, while the **death rate** continues to fall **rapidly** due to improved healthcare, sanitation, and nutrition. - This significant decline in the death rate, coupled with a still high birth rate, results in a rapid and substantial increase in **population growth** (demographic explosion). - The key characteristic is the **greater rate of decline** in death rate compared to birth rate. *Birth Rate remains consistently high while Death Rate starts to decline significantly* - The word **"starts"** is the critical error here - it describes the **Early Expanding Phase**, not the Late Expanding Phase. - In the **Late Expanding Phase**, the death rate has *already been declining* and continues to decline rapidly. - The death rate decline **begins** in the Early Expanding Phase, not the Late Expanding Phase. *Death Rate becomes significantly lower than Birth Rate during this phase* - While this statement is true, it describes a **consequence** rather than the defining characteristic of the Late Expanding Phase. - This condition exists throughout the expanding phases, making it less specific. - The defining feature is the **rate of decline** of death rate being greater than any decline in birth rate. *Birth Rate remains higher than Death Rate, leading to population growth* - This statement is true but **too generic** - it applies to all expanding phases where population growth occurs. - It does not specifically distinguish the **Late Expanding Phase** from the Early Expanding Phase. - The unique feature of the Late Expanding Phase is the **rapid and dramatic decline** in death rate while birth rate remains high.
Question 24: What does the net reproduction rate indicate?
- A. Number of live births per 1000 mid-year population
- B. Number of live births per 1000 women of child bearing age
- C. Average number of daughters a newborn girl will have during her lifetime (Correct Answer)
- D. None of the options
Explanation: ***Average number of daughters a newborn girl will have during her lifetime*** - The **net reproduction rate (NRR)** specifically measures the average number of **daughters** a newborn girl is expected to have throughout her reproductive years, taking into account **mortality** rates. - An NRR of 1 indicates that each generation of women is exactly replacing itself, while an NRR greater or less than 1 suggests population growth or decline, respectively. - This is the **correct definition** of NRR and focuses on female offspring as they are the ones who will contribute to the next generation. *Number of live births per 1000 mid-year population* - This describes the **crude birth rate (CBR)**, which is a general measure of fertility but does not account for the age and sex structure of the population or mortality rates. - It includes all live births in relation to the total population, not specifically focusing on the generational replacement of females. *Number of live births per 1000 women of child bearing age* - This definition refers to the **general fertility rate (GFR)**, which is a more refined measure of fertility than the crude birth rate, as it focuses on women in their reproductive years (typically 15-49 years). - However, it still does not track the replacement of daughters who will become mothers, nor does it factor in mortality within the female population. *None of the options* - This option is incorrect because one of the given options accurately defines the net reproduction rate. - The net reproduction rate is a well-established demographic indicator used in population studies and public health planning.
Question 25: Which agency monitors air quality in India?
- A. None of the above
- B. Central pollution control board (Correct Answer)
- C. Central air quality board
- D. Central public works dept
Explanation: ***Central pollution control board*** - The **Central Pollution Control Board (CPCB)** is responsible for setting standards and monitoring air quality across India. - It works under the **Ministry of Environment, Forest and Climate Change (MoEFCC)**. *Central air quality board* - There is **no specific agency** or board named "Central Air Quality Board" in India. - Air quality monitoring falls under the broader mandate of pollution control. *Central public works dept* - The **Central Public Works Department (CPWD)** is primarily involved in the construction and maintenance of government buildings and infrastructure. - It does **not have a mandate** for environmental monitoring like air quality. *None of the options* - This option is incorrect because the **Central Pollution Control Board** is the correct agency responsible for air quality monitoring. - There is a specific statutory organization fulfilling this role.
Question 26: In which of the following diseases is mass vaccination considered ineffective?
- A. Tetanus (Correct Answer)
- B. None of the options
- C. Measles
- D. Polio
Explanation: ***Correct: Tetanus*** - Mass vaccination is considered **ineffective** for tetanus because it is **not a communicable disease** transmitted person-to-person - Tetanus is caused by **Clostridium tetani** spores present in soil and environment - Since there is **no herd immunity** benefit, vaccinating large populations simultaneously does not break any chain of transmission - **Individual immunization** with tetanus toxoid is highly effective for personal protection, but this is different from mass vaccination strategies used for communicable diseases - The focus for tetanus prevention is on **universal immunization** and **wound management**, not mass campaigns *Incorrect: Measles* - Mass vaccination for measles is **highly effective** due to its person-to-person transmission - Achieving high vaccination coverage (>95%) provides **herd immunity** and can lead to **elimination** - The **MMR vaccine** is a cornerstone of mass immunization programs worldwide *Incorrect: Polio* - Mass vaccination campaigns (Pulse Polio) have been **extremely effective** in nearly eradicating polio globally - The disease spreads through the fecal-oral route, making mass vaccination crucial for breaking transmission chains - Both **OPV** and **IPV** provide individual and community protection through herd immunity *Incorrect: None of the options* - This is incorrect because tetanus is a clear example where mass vaccination strategy is ineffective due to lack of person-to-person transmission
Question 27: Secondary prevention is applicable to
- A. Early stage of disease (Correct Answer)
- B. Factors leading to disease
- C. Advanced stage of disease
- D. None of the options
Explanation: ***Early stage of disease*** - **Secondary prevention** focuses on early detection and prompt treatment to halt the progression of an existing disease. - This stage is crucial for interventions like **screening tests** and **early diagnosis**, which aim to minimize the impact of the disease once it has begun. *Factors leading to disease* - This relates to **primary prevention**, which aims to prevent the disease from occurring in the first place by addressing risk factors or promoting health. - Examples include **vaccination** or promoting healthy lifestyle choices. *Advanced stage of disease* - This is the domain of **tertiary prevention**, which focuses on managing the disease, preventing complications, and improving quality of life once the disease is well-established. - Rehabilitation and long-term care are key aspects of this stage. *None of the options* - This option is incorrect because secondary prevention specifically targets the **early stage of disease** to prevent further progression and adverse outcomes.
Question 28: Which method is primarily used to assess HIV prevalence?
- A. Sentinel surveillance in high-risk populations (Correct Answer)
- B. Passive surveillance through reporting systems
- C. Disease registries for HIV patients
- D. Active case finding through outreach programs
Explanation: ***Sentinel surveillance in high-risk populations*** - **Sentinel surveillance** focuses on specific, well-defined groups, such as pregnant women or individuals attending STD clinics, to get a representative estimate of **HIV prevalence** in the broader community. - This method is particularly effective for diseases that are difficult to track through general population surveys due to stigma or low overall prevalence. *Passive surveillance through reporting systems* - **Passive surveillance** relies on healthcare providers voluntarily reporting cases, which often leads to **underreporting** and an incomplete picture of an epidemic's true scope. - It primarily captures known cases rather than estimating the overall **prevalence** within a population. *Disease registries for HIV patients* - **Disease registries** are valuable for tracking the natural history, treatment outcomes, and long-term trends among *diagnosed* individuals, but they do not capture undiagnosed cases, thus not accurately representing **prevalence**. - They provide data on incidence (new cases) and patient management but are less suited for estimating the total number of people living with the disease at a given time. *Active case finding through outreach programs* - **Active case finding** aims to identify new cases within specific communities, usually in response to an outbreak or in populations with known high risk. - While it identifies undiagnosed individuals, its primary goal is case identification and linkage to care, rather than providing a **statistically representative prevalence** estimate for an entire population.
Question 29: What is the most common cancer diagnosed in men?
- A. Bladder cancer
- B. Colorectal cancer
- C. Oral cancer (Correct Answer)
- D. Prostate cancer
Explanation: ***Oral cancer*** - **Oral cancer** is the most common cancer diagnosed in men in India, particularly cancers of the **lip, oral cavity, and oropharynx**. - India accounts for approximately **one-third of the global burden** of oral cancers. - Major risk factors include **tobacco chewing (gutka, pan masala, betel quid), smoking, and alcohol consumption**. - Early detection through **oral examination** and avoiding tobacco products are key preventive measures. *Prostate cancer* - While prostate cancer is the most common cancer in men in **Western populations**, it ranks **much lower in India** (typically 3rd-5th most common). - Incidence is increasing in urban Indian populations due to improved detection and lifestyle changes. *Bladder cancer* - **Bladder cancer** is significant but less common than oral cancer in Indian men. - Risk factors include **smoking** and occupational exposure to chemicals. *Colorectal cancer* - **Colorectal cancer** is increasing in incidence in India but remains less common than oral cancer in men. - Screening with **colonoscopy** is recommended for early detection, especially in those with family history.
Question 30: Which disease is associated with a propagative cycle?
- A. None of the options
- B. Plague
- C. Filaria (Correct Answer)
- D. Malaria
Explanation: ***Filaria*** - The **filarial worm** undergoes a **biological transmission cycle** in the mosquito vector where microfilariae develop through larval stages (L1 → L2 → L3) with multiplication. - This represents a **cyclopropagative cycle** (both development and multiplication occur in the vector). - In the context of this question and classical teaching, filaria is considered the standard example of biological transmission with vector multiplication. - The infective L3 larvae multiply from a single microfilaria, and multiple larvae can develop within one mosquito. *Plague* - **Plague** (*Yersinia pestis*) is transmitted by fleas through **mechanical transmission**. - Bacteria multiply in the flea's gut causing blockage (blocking transmission), but this is not considered a true biological cycle. - The pathogen does not undergo developmental stages in the vector. *Malaria* - **Malaria** (*Plasmodium* spp.) undergoes the **sporogonic cycle** in the mosquito, which is also a **cyclopropagative cycle**. - Gametocytes → ookinete → oocyst → sporozoites (development with multiplication). - While biologically similar to filaria, in classical epidemiology teaching, filaria is more commonly cited as the example for propagative transmission. *None of the options* - This option is incorrect as filaria demonstrates biological transmission with multiplication in the vector. - Both filaria and malaria technically undergo cyclopropagative cycles, but filaria is the conventional answer in medical education contexts.