In the context of public health, which statistical measure is most commonly used to assess the variability of health-related data?
Which scheme aims to empower adolescent girls in India through holistic development and empowerment?
Which graphical representation is best suited for depicting continuous quantitative data?
Berksonian bias is a type of ?
What is the term for the time between infection and maximum infectivity?
Which cancer type has the most effective screening procedure?
Which vaccine is used to prevent cholera?
What is the concentration of type 3 virus in the trivalent oral polio vaccine?
Botulism is most commonly due to -
Vector of scrub typhus in man?
NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs
Question 81: In the context of public health, which statistical measure is most commonly used to assess the variability of health-related data?
- A. Mean
- B. Range
- C. Variance
- D. Standard deviation (Correct Answer)
Explanation: ***Standard deviation*** - The **standard deviation** is the most common measure of **variability** in public health, as it quantifies the average amount of dispersion or spread around the mean. - It is particularly useful because it is expressed in the same units as the original data, making it easy to interpret and compare differences in health outcomes. *Mean* - The **mean** is a measure of **central tendency**, representing the average value of a dataset. - While essential for understanding the typical value, it does not provide information about the **spread or variability** of the data. *Range* - The **range** is the difference between the **maximum and minimum values** in a dataset, offering a rudimentary measure of variability. - It is highly susceptible to **outliers** and does not give a comprehensive picture of data distribution, as it only considers two values. *Variance* - **Variance** measures the average of the **squared differences** from the mean, providing an indication of how far data points deviate from the average. - While closely related to standard deviation, its units are squared, making it less intuitive for direct interpretation of variability compared to the **standard deviation**.
Question 82: Which scheme aims to empower adolescent girls in India through holistic development and empowerment?
- A. Beti Bachao Beti Padhao Scheme
- B. Balika Samriddhi Yojana (Correct Answer)
- C. Kanya Sumangala Yojana
- D. Sukanya Samriddhi Yojana
Explanation: ***Balika Samriddhi Yojana*** - Launched in **1997** by the Government of India specifically to promote the **holistic development and empowerment** of girl children. - Provides **financial assistance** at birth and scholarships at various educational milestones (Class I, III, V, VI-VII, VIII, IX-X) to support their education and development. - Aims to change societal attitudes towards the girl child, reduce gender discrimination, and ensure their **overall development** through sustained financial support. - This scheme directly addresses **empowerment through holistic development** by covering both immediate needs and long-term educational goals. *Sukanya Samriddhi Yojana* - This is a **savings scheme** launched in **2015** as part of the Beti Bachao Beti Padhao campaign. - Focuses on **financial security** through savings for future education and marriage expenses, not holistic development programs. - Parents/guardians deposit money regularly; it does not provide direct financial assistance or scholarships for development milestones. *Beti Bachao Beti Padhao Scheme* - Launched in **2015** as a national campaign to address declining **Child Sex Ratio (CSR)** and promote girls' education. - Primarily an **awareness and advocacy program** focusing on prevention of female feticide and gender-biased sex selection. - While it promotes education and gender equality, it is not a direct empowerment scheme providing financial support for holistic development. *Kanya Sumangala Yojana* - This is a **state-level scheme** launched in **2019** by the Uttar Pradesh government. - Provides financial assistance in six installments from birth to graduation to promote girls' welfare. - While similar in concept to Balika Samriddhi Yojana, it was launched much later and is limited to one state.
Question 83: Which graphical representation is best suited for depicting continuous quantitative data?
- A. Bar diagram
- B. Pie chart
- C. Histogram (Correct Answer)
- D. Pictogram
Explanation: **Histogram** - A **histogram** is specifically designed for depicting the distribution of **continuous quantitative data** by dividing the data into bins and showing the frequency of data points within each bin. - The bars in a histogram are adjacent, indicating the continuous nature of the data and representing ranges of values. *Bar diagram* - A **bar diagram** (or bar chart) is typically used for comparing **discrete categories** or displaying changes over time for categorical data. - The bars in a bar diagram are usually separated, emphasizing distinct categories rather than continuous ranges. *Pie chart* - A **pie chart** is used to show the **proportions of a whole**, representing parts of a composition for categorical data. - It is not suitable for continuous data as it provides no information about the distribution or frequency across a range of values. *Pictogram* - A **pictogram** uses images or icons to represent data, making it visually engaging, but it is generally used for **simple comparisons of discrete or categorical data**. - It lacks the precision and detail required to accurately depict the distribution or frequency of continuous quantitative data.
Question 84: Berksonian bias is a type of ?
- A. Selection bias (Correct Answer)
- B. Information bias
- C. Interviewer bias
- D. Recall bias
Explanation: ***Selection bias*** - **Berkson's bias** is a form of **selection bias** that arises in studies conducted using hospital data. - It occurs when the probability of admission to a hospital or inclusion in a study is conditional on both exposure and disease status, leading to a **flawed association** between them. *Interviewer bias* - **Interviewer bias** is a type of **information bias** where the interviewer's expectations or knowledge about the study or participants influence the way information is sought or recorded. - This typically affects the **data collection process** and not the selection of participants. *Information bias* - **Information bias** is a broad category of biases that arise from **systematic errors in measurement** or classification of exposure or disease. - While Berkson's bias can lead to misinformation, its root cause is in how subjects are selected, not how data on those subjects is collected after selection. *Recall bias* - **Recall bias** is a type of **information bias** where there are systematic differences in the way participants **recall past events or exposures**. - It is particularly common in **case-control studies** where individuals with a disease may remember exposures differently than healthy controls.
Question 85: What is the term for the time between infection and maximum infectivity?
- A. Communicable period
- B. Generation time (Correct Answer)
- C. Incubation period
- D. Serial interval
Explanation: ***Generation time*** - This is the **time interval** between receipt of infection by a host and the moment of **maximum infectivity** of that same host. - It is a crucial parameter in epidemiology for understanding **disease transmission dynamics** and the speed at which an epidemic can spread. *Incubation period* - This refers to the time from **exposure to an infectious agent** until the **onset of symptoms**. - It does not directly account for the timing of viral shedding or peak infectivity. *Serial interval* - This is the time between **symptom onset in a primary case** and **symptom onset in a secondary case** it infects. - While related to transmission, it focuses on symptomatic presentation rather than peak infectivity. *Communicable period* - This is the time during which an infected individual is **capable of transmitting** the infectious agent to others. - It represents the entire duration of potential transmission, not specifically the peak infectivity.
Question 86: Which cancer type has the most effective screening procedure?
- A. Prostate Cancer
- B. Colon Cancer
- C. Cervical Cancer (Correct Answer)
- D. Gastric Cancer
Explanation: ***Cervical Cancer*** - **Pap smear and HPV testing** represent the most effective cancer screening program, with proven reduction of **>70% in cervical cancer incidence and mortality**. - Screening detects **pre-cancerous lesions (CIN)** during the long latent period, allowing for effective intervention before cancer develops. - Well-established guidelines with high sensitivity, specificity, and cost-effectiveness make it a **public health success story**. - Particularly relevant in Indian context where cervical cancer burden is high and screening programs are being expanded. *Colon Cancer* - **Colonoscopy** and **fecal occult blood testing (FOBT)** are highly effective, allowing direct visualization and removal of precancerous polyps. - While very effective with proven mortality reduction, screening uptake is lower and the procedure is more invasive than cervical cancer screening. - Effectiveness is comparable but cervical cancer screening has achieved greater population-level impact historically. *Prostate Cancer* - Screening with **PSA (prostate-specific antigen) testing** and **digital rectal exam (DRE)** is controversial due to potential for **overdiagnosis and overtreatment** of indolent cancers. - Impact on overall mortality reduction is debated, and it doesn't prevent cancer through detection of precancerous lesions like cervical/colon cancer screening. *Gastric Cancer* - **Gastric cancer screening** is not routinely recommended in most countries including India due to lower prevalence and lack of a highly effective, non-invasive screening method. - **Endoscopy** can detect gastric cancer but is typically performed in symptomatic individuals or high-risk populations (e.g., Japan, Korea), not as a general population screening tool.
Question 87: Which vaccine is used to prevent cholera?
- A. CVD 103-HgR
- B. Ty21 A
- C. WC-rBS (Correct Answer)
- D. None of the options
Explanation: ***WC-rBS*** * **WC-rBS** stands for **whole-cell, recombinant B subunit** vaccine, also known as **Dukoral**. * It is an **oral inactivated vaccine** containing killed *Vibrio cholerae* O1 bacteria and the recombinant B subunit of the cholera toxin, providing immunity against cholera. * **WC-rBS is the WHO-prequalified cholera vaccine** widely used in India and recommended for travellers and in epidemic settings. * It provides protection against both O1 and O139 serogroups and offers some cross-protection against ETEC (enterotoxigenic *E. coli*). *CVD 103-HgR* * **CVD 103-HgR** (commercially known as **Vaxchora**) is an **oral live-attenuated cholera vaccine** approved by the FDA. * It is a genetically modified *Vibrio cholerae* O1 Inaba strain with deleted cholera toxin genes. * While this is also a cholera vaccine, **it is primarily used in the United States** and is not the standard vaccine used in India or recommended by WHO for mass vaccination campaigns. * In the Indian context and for NEET-PG examinations, **WC-rBS (Dukoral) is the recognized cholera vaccine**. *Ty21a* * **Ty21a** is an **oral live-attenuated vaccine** used to prevent **typhoid fever**. * It is specifically designed to target *Salmonella Typhi* bacteria, not *Vibrio cholerae*. *None of the options* * This option is incorrect because WC-rBS is the well-established and WHO-recommended vaccine for the prevention of cholera in the Indian context.
Question 88: What is the concentration of type 3 virus in the trivalent oral polio vaccine?
- A. 400,000 TCID 50
- B. 100,000 TCID 50
- C. 300,000 TCID 50
- D. 600,000 TCID 50 (Correct Answer)
Explanation: ***600,000 TCID 50*** - The **trivalent oral polio vaccine (tOPV)** traditionally contained specific concentrations of each serotype: **type 1 (1,000,000 TCID50/dose)**, **type 2 (100,000 TCID50/dose)**, and **type 3 (600,000 TCID50/dose)**. - Type 3 poliovirus requires a **higher concentration (600,000 TCID50)** compared to type 2 to achieve adequate immunogenicity and protection. - The **World Health Organization (WHO)** established these specific formulations for tOPV to ensure optimal efficacy and safety for each serotype. *100,000 TCID 50* - This is the concentration of **type 2 poliovirus** in tOPV, not type 3. - Due to the **global eradication of wild poliovirus type 2** by 2015, tOPV was replaced with bivalent OPV (bOPV) containing only types 1 and 3 in routine immunization programs. *400,000 TCID 50* - This concentration does not correspond to any standard poliovirus serotype in the traditional trivalent oral polio vaccine. - This value falls between type 2 (100,000) and type 3 (600,000) concentrations but is not used. *300,000 TCID 50* - This concentration is not the standard for any poliovirus serotype in the traditional trivalent oral polio vaccine. - Each serotype has a **distinct, empirically determined concentration** to achieve optimal immunity while minimizing adverse effects.
Question 89: Botulism is most commonly due to -
- A. Egg
- B. Milk
- C. Meat
- D. Home-canned vegetables (Correct Answer)
Explanation: ***Home-canned vegetables*** - **Home-canned vegetables** are the **most common** source of botulism, particularly improperly processed low-acid vegetables like beans, corn, and asparagus - *Clostridium botulinum* spores survive inadequate heat treatment and germinate in the **anaerobic, low-acid environment** of improperly canned foods - The **lack of sufficient heat sterilization** (pressure canning at 121°C/250°F is required) allows spore survival and subsequent toxin production - Most foodborne botulism outbreaks are traced to **home-canned vegetables** rather than commercially processed foods *Meat* - While improperly preserved meats can cause botulism, they are **not the most common source** in epidemiological data - Commercial meat processing standards and refrigeration significantly reduce this risk - Meat-associated botulism is more common in certain cultural practices involving fermented or preserved meats *Egg* - **Eggs** are not associated with botulism as they do not provide the anaerobic environment necessary for *Clostridium botulinum* toxin production - Eggs are more commonly linked to **Salmonella infections** if improperly handled or undercooked *Milk* - **Milk** and dairy products are not typical sources of botulism - **Pasteurization** and refrigeration prevent conditions favorable for *C. botulinum* growth - Dairy products are more associated with **Listeria** or **Campylobacter** if contaminated
Question 90: Vector of scrub typhus in man?
- A. O. tsutsugamushi
- B. Leptotrombidium deliense (Correct Answer)
- C. Lice
- D. Pediculus humanus
Explanation: ***Leptotrombidium deliense*** - This is the **chigger mite** species primarily responsible for transmitting **scrub typhus** to humans. - **Larval mites (chiggers)** of this species feed on human skin and transmit the bacterium *Orientia tsutsugamushi*. *O. tsutsugamushi* - This is the **causative agent** of scrub typhus, not the vector. - It is a **rickettsial bacterium** transmitted by infected chiggers. *Lice* - **Lice** (e.g., *Pediculus humanus corporis*) are vectors for diseases like **epidemic typhus** (caused by *Rickettsia prowazekii*) and **relapsing fever**, but not scrub typhus. - They are **blood-sucking insects** distinct from mites. *Pediculus humanus* - This refers to **human lice**, specifically *Pediculus humanus capitis* (head louse) or *Pediculus humanus corporis* (body louse). - As mentioned, lice transmit diseases like epidemic typhus, not **scrub typhus**.