Epidemiology Practice Questions

Q: There has been a gradual increase in number of non-communicable disease cases as compared to previous years. This trend is called:

Secular. ***Secular*** - A **secular trend** refers to a long-term change or trend in the frequency of a disease or health condition over an extended period, often years or decades. - The gradual increase in the number of non-communicable disease cases over previous years is a classic example of a **secular trend**. *Periodical* - **Periodical** variations typically refer to patterns that repeat at regular intervals but are much shorter than long-term secular trends (e.g., daily, weekly). - This term does not capture the **long-term, evolving nature** of the health trend described. *Cyclical* - A **cyclical trend** describes fluctuations in disease incidence that occur over periods longer than a year, but still demonstrate a predictable, repeating cycle, often related to socioeconomic or environmental factors (e.g., a disease peaking every few years). - While it describes patterns, it implies **repetition** rather than a continuous, unidirectional increase over time. *Seasonal* - **Seasonal trends** describe variations in disease occurrence that are related to specific seasons of the year, such as the increase in influenza cases during winter. - This term specifically refers to **annual fluctuations** and does not describe a gradual increase over many years.

Q: True about epidemiology of cholera-

Food can transmit the disease. ***Food can transmit the disease*** - Cholera is commonly transmitted through the **fecal-oral route**, and **contaminated food** is a significant vehicle for this transmission. - Food can become contaminated when handled by infected individuals or prepared with **contaminated water**. *Boiling water cannot destroy the organism* - **Boiling water** for at least one minute is a highly effective method for killing Vibrio cholerae, the bacterium responsible for cholera. - High temperatures denature proteins and disrupt the cellular structure of the bacteria, rendering it inactive. *Vaccination gives 90% protection* - Oral cholera vaccines typically provide **modest protection**, ranging from 50% to 85% for a limited duration, usually around 2-5 years. - No vaccine offers 90% protection against cholera, and protection wanes over time, necessitating booster doses or revaccination. *Cholera cannot be transmitted by contaminated water* - **Contaminated water** is the primary mode of cholera transmission. - Drinking water contaminated with **Vibrio cholerae**, often from feces of infected individuals, is the most common cause of outbreaks.

Q: Which of the following studies has given coronary risk factors?

Framingham. ***Framingham*** - The **Framingham Heart Study** is a landmark prospective cohort study that has identified many of the well-known **risk factors for cardiovascular disease**, including hypertension, high cholesterol, smoking, and diabetes. - This ongoing study, started in 1948, has been instrumental in shaping our understanding of **coronary artery disease** development and prevention strategies. *North Karelia* - The **North Karelia Project** was a comprehensive community-based prevention program in Finland that successfully reduced cardiovascular disease risk factors. - While influential in demonstrating how to **implement prevention strategies**, it applied already-known risk factors rather than discovering new ones. - The program focused on reducing smoking, cholesterol, and blood pressure in the population. *Stanford study* - While Stanford University has conducted numerous influential medical studies, there isn't a single "Stanford study" primarily recognized for giving us the comprehensive list of coronary risk factors. - Many institutions contribute to medical knowledge, but the **Framingham Heart Study** stands out for this specific contribution. *MONICA* - The **MONICA (Monitoring Trends and Determinants in Cardiovascular Disease)** Project was a multinational WHO project that aimed to monitor cardiovascular disease trends and determinants. - While it provided valuable data on the **epidemiology of cardiovascular disease** and its risk factors, it primarily assessed trends in established risk factors rather than initially identifying them.

Q: Species of Anopheles causing malaria in Andaman & Nicobar island?

Anopheles epiroticus. ***Anopheles epiroticus (formerly Anopheles sundaicus)*** - **Anopheles epiroticus** is the **primary malaria vector in the Andaman & Nicobar Islands**. - It belongs to the **Anopheles sundaicus complex** and is highly adapted to **coastal and island ecosystems**. - It breeds in **brackish water** and is an efficient vector for both **Plasmodium falciparum** and **Plasmodium vivax**. - This species is characteristic of **coastal Southeast Asia** and island territories. *Anopheles dirus* - **Anopheles dirus** is a primary vector in **forest-fringed areas** of mainland Southeast Asia and northeastern India. - While it is an efficient malaria vector, it is **not the predominant species** in the Andaman & Nicobar Islands. - It typically breeds in **shaded pools** in forested areas. *Anopheles stephensi* - **Anopheles stephensi** is a major **urban and rural** malaria vector in mainland India and the Middle East. - It is adapted to **urban environments** and breeds in artificial containers. - It is **not found** in the Andaman & Nicobar Islands. *Anopheles culicifacies* - **Anopheles culicifacies** is the most widespread rural malaria vector in the **Indian subcontinent**. - It breeds in **rice fields**, irrigation channels, and other shallow freshwater bodies. - It is **not present** in the Andaman & Nicobar Islands due to the distinct island ecology.

Q: Index for estimating epidemic of plague?

Cheopis index. ***Cheopis index*** - This index is specifically used to assess the potential for a **plague outbreak** by measuring the average number of **Xenopsylla cheopis (oriental rat flea)** per rat. - A value of **1 or more** indicates a high risk of plague transmission. *Burrow index* - The burrow index is used to estimate rodent population density by counting **active burrows**. - While relevant to rodent control, it does not directly measure the **flea burden specific to plague transmission**. *Total flea index* - The total flea index is the average number of **all flea species** per rodent. - While it gives a general idea of flea infestation, it's not as specific as the Cheopis index for **plague transmission risk**, which primarily involves **X. cheopis**. *None of the options* - The **Cheopis index** is a well-established and widely used epidemiological tool for assessing plague risk. - Therefore, there is a correct option among the choices provided.

Q: Among various species of mosquitoes belonging to Anopheles genus, one that is highly anthropophilic and transmits even at low density is

Anopheles fluviatilis. ***Anopheles fluviatilis*** - This species is known for being **highly anthropophilic** (prefers human blood) and having a high vectorial capacity, allowing it to transmit malaria effectively even at **low mosquito densities**. - Its efficient transmission at low densities makes it a significant vector, particularly in forest and foothill regions. *Anopheles culicifacies* - This is a major vector in rural India, particularly prevalent in **agricultural areas** and at higher densities. - While an important vector, it is generally associated with higher densities for efficient transmission compared to *An. fluviatilis*. *Anopheles stephensi* - This species is a primary vector in **urban and peri-urban areas**, adapted to breeding in domestic water containers. - While anthropophilic, its transmission efficiency at very low densities is not as pronounced as *An. fluviatilis* in its characteristic habitats. *Anopheles sundaicus* - This species is typically found in **coastal saline or brackish water** breeding sites in Southeast Asia. - While it is an important vector in those specific ecological niches, it doesn't possess the same level of efficient low-density transmission and broad anthropophilic behavior as *An. fluviatilis* across different settings.

Q: Incidence of TB in a community is measured by

Sputum smear positive. ***Sputum smear positive*** - The **incidence of TB** in a community is best measured by the number of new **sputum smear-positive** cases, as these individuals are actively shedding bacilli and are infectious. - This method directly identifies individuals with **active disease** who are capable of transmitting the infection, thus reflecting new cases rather than past exposure. *Tuberculin test positive* - A **positive tuberculin test** (or TST) indicates exposure to TB bacilli and an immune response, but it does not differentiate between **latent TB infection (LTBI)** and active disease. - Many individuals with a positive test will never develop active TB, making it a poor measure of the *incidence of new active cases*. *Mantoux test positive* - The **Mantoux test** is another name for the **tuberculin skin test (TST)**, yielding the same limitations as "tuberculin test positive." - It primarily measures **delayed-type hypersensitivity** to tuberculin proteins, reflecting prior exposure rather than current, active, and transmissible disease. *Sputum culture* - While **sputum culture** is the gold standard for diagnosing active TB disease due to its high sensitivity, it is more expensive and time-consuming than sputum smear microscopy. - For measuring incidence at a community level, **sputum smear positivity** is often preferred for its practicality, speed, and ability to identify the most infectious cases promptly.

Question 1

There has been a gradual increase in number of non-communicable disease cases as compared to previous years. This trend is called:

Accepted Answer

Secular

Answer

Periodical

Answer

Cyclical

Answer

Seasonal

Question 2

True about epidemiology of cholera-

Accepted Answer

Food can transmit the disease

Answer

Boiling water cannot destroy the organism

Answer

Vaccination gives 90% protection

Answer

Cholera cannot be transmitted by contaminated water

Question 3

Which of the following studies has given coronary risk factors?

Accepted Answer

Framingham

Answer

Stanford study

Answer

MONICA

Answer

North Karelia

Question 4

Species of Anopheles causing malaria in Andaman & Nicobar island?

Accepted Answer

Anopheles epiroticus

Answer

Anopheles dirus

Answer

Anopheles stephensi

Answer

Anopheles culicifacies

Question 5

Index for estimating epidemic of plague?

Accepted Answer

Cheopis index

Answer

Burrow index

Answer

Total flea index

Answer

None of the options

Question 6

Key indicator for AFP surveillance?

Accepted Answer

At least one case of non-polio AFP per year per 100000 population of under 15 years

Answer

At least one case of non-polio AFP per year per 1000 population of under 5 years

Answer

At least one case of non-polio AFP per year per 10000 population of under 15 years

Answer

At least one case of non-polio AFP per year per 100000 population of under 5 years

Question 7

Which one of the following statements about influence of smoking on risk of Coronary Heart Disease is not true?

Accepted Answer

Influence of smoking is only additive to other risk factors for CHD

Answer

Influence of smoking is synergistic to other risk factors for CHD

Answer

Influence of smoking is independent of other risk factors for CHD

Answer

Influence of smoking is directly related to number of cigarettes smoked per day

Question 8

Among various species of mosquitoes belonging to Anopheles genus, one that is highly anthropophilic and transmits even at low density is

Accepted Answer

Anopheles fluviatilis

Answer

Anopheles culicifacies

Answer

Anopheles stephensi

Answer

Anopheles sundaicus

Question 9

There are 40 new cases of carcinoma of breast per 100,000 women/ year in country 'X' & 100 new cases / 100,000 women/ year in Country 'Y'. Based on this statistical data which of the following statement is true?

Accepted Answer

Country 'X' has more number of younger women than country 'Y'

Answer

More women in Country 'Y' are smokers

Answer

More preventive & screening measures like mammography are available in Country 'X'

Answer

More women in Country 'X' had breastfed their children

Question 10

Incidence of TB in a community is measured by

Accepted Answer

Sputum smear positive

Answer

Tuberculin test positive

Answer

Mantoux test positive

Answer

Sputum culture

Epidemiology — MCQs

Epidemiology — MCQs

On this page

Practice by Chapter

Want unlimited practice?