Epidemiology Practice Questions

Q: The pattern of change in disease trends where infectious diseases are replaced by degenerative and non-communicable diseases as the main causes of morbidity and mortality is known as:

Epidemiological transition. ***Epidemiological transition*** - The **epidemiological transition** describes the shift in disease patterns from infectious diseases as leading causes of death to non-communicable, chronic, and degenerative diseases. - This transition is typically associated with **socioeconomic development**, improved public health, sanitation, and increased life expectancy. - It was first described by **Abdel Omran** in 1971 and includes three stages: the age of pestilence and famine, the age of receding pandemics, and the age of degenerative and man-made diseases. *Incorrect: Paradoxical transition* - This term is **not a recognized concept** in epidemiology. - It does not describe a systemic pattern of disease trend changes. *Incorrect: Demographic transition* - The **demographic transition** refers to changes in birth and death rates over time in a population, leading to shifts in age structure. - While related to epidemiological changes, it specifically describes **population dynamics**, not disease patterns themselves. - It typically precedes or accompanies epidemiological transition. *Incorrect: Cross transition* - This term is **not a recognized concept** in epidemiology. - It does not describe a systemic pattern of disease trend changes.

Q: The time interval between reception of infection and maximum infectivity of the host is known as-

Latent period. ***Latent period*** - This is the time from **infection to infectiousness**, meaning the period until the host can transmit the pathogen to another susceptible host. - The highest infectivity typically occurs during this period or shortly after its completion, making it a critical measure for understanding disease transmission. *Median incubation period* - The **incubation period** is the time from exposure to a pathogen until the first appearance of symptoms. - The median incubation period represents the **midpoint** of this time frame across an infected population. *Generation time* - **Generation time** is defined as the interval between the onset of infectiousness in a primary case and the onset of infectiousness in a secondary case infected by the primary case. - It measures the **time between successive generations of infection**, not the time to maximum infectivity within a single host. *Serial interval* - The **serial interval** is the time from symptom onset in a primary case to symptom onset in a secondary case infected by the primary case. - It is a measure related to the **spread of symptomatic illness**, and while often correlated with generation time, it is not specifically about the host's infectivity level.

Q: WER stands for

Weekly epidemiological record. ***Weekly epidemiological record*** - The **Weekly Epidemiological Record (WER)** is a key publication of the **World Health Organization (WHO)**. - It serves as an essential instrument for the rapid dissemination of **epidemiological information** on cases and outbreaks of diseases under the **International Health Regulations**. *World epidemic record* - This option is incorrect because while the WER deals with **epidemics**, the full and correct name emphasizes the **weekly publication schedule** and broader "epidemiological" scope, not just "epidemic." - Using "World epidemic record" is not the accepted or official nomenclature for the publication. *Weekly environmental record* - This option is incorrect as the **WER** focuses specifically on **disease surveillance** and **epidemiology**, not environmental data. - While environmental factors can influence disease, the primary scope of the WER is on disease prevalence, incidence, and outbreaks. *World epidemiological record* - This option is incorrect because the official publication is called the **"Weekly" Epidemiological Record**, highlighting its regular, week-by-week updates. - Omission of "Weekly" changes the accuracy of the title.

Q: Disease highly transmitted during incubation period is -

Chickenpox. ***Chickenpox (Varicella)*** - Chickenpox is **highly contagious during the late incubation period**, specifically **1-2 days before the rash appears**. - The incubation period is 10-21 days (usually 14-16 days), and transmission begins **before any clinical symptoms** are evident. - This makes chickenpox unique as it spreads efficiently during the true incubation period (asymptomatic phase). - Transmission continues until **all lesions have crusted over** (usually 5-7 days after rash onset). *Measles* - While measles is highly contagious, it is most infectious during the **prodromal phase** (fever, cough, coryza, conjunctivitis) and early rash phase. - The prodromal phase occurs **after the incubation period ends** (incubation is 10-14 days of asymptomatic infection). - Some transmission may occur in the last 1-2 days of incubation, but peak infectivity is during the symptomatic prodromal phase. *Pertussis* - Pertussis is most contagious during the **catarrhal stage**, which follows the incubation period. - The catarrhal stage is characterized by runny nose, low-grade fever, and mild cough (symptomatic phase). - Infectivity decreases significantly after 3 weeks of illness or after 5 days of appropriate antibiotic therapy. *Cholera* - Cholera is transmitted via the **fecal-oral route** through contaminated water or food. - While some bacterial shedding occurs during incubation, peak transmission happens during the **symptomatic phase** with severe diarrhea causing massive bacterial shedding. - Most transmission occurs from symptomatic or recently symptomatic individuals.

Q: Population of a village on 1st January is 16,500. Since 1st January, 22 new cases of TB were detected during the year. Total registered cases were 220. What is the incidence of TB?

133 per 100,000. ***133 per 100,000*** - The **incidence rate** calculates the frequency of new occurrences of a disease in a population over a specified time period. - It is calculated as (Number of new cases / Population at risk) * 100,000. Here, (22 / 16,500) * 100,000 = **133.33 per 100,000**. *100 per 100,000* - This value would be obtained if the number of new cases was 16.5 (16.5 / 16,500 * 100,000). - This calculation does not reflect the given number of **new cases (22)**. *121 per 100,000* - This value would be obtained if the number of new cases was 20 (20 / 16,500 * 100,000) or if the **population was different**. - This option does not match the actual data provided for the new cases and population. *111 per 100,000* - This value would be obtained if the number of new cases was approximately 18.3 (18.3 / 16,500 * 100,000). - It does not correctly reflect the **incidence calculation** based on the given number of 22 new cases.

Question 1

Which of the following is true about annual risk of TB (ARI)

Accepted Answer

It is assessed by tuberculin conversion in previously non-vaccinated children

Answer

ARI of 1% = 50 new cases

Answer

It represents new cases of TB

Answer

Current ARI in India is 1.7%

Question 2

The pattern of change in disease trends where infectious diseases are replaced by degenerative and non-communicable diseases as the main causes of morbidity and mortality is known as:

Accepted Answer

Epidemiological transition

Answer

Paradoxical transition

Answer

Demographic transition

Answer

Cross transition

Question 3

The time interval between reception of infection and maximum infectivity of the host is known as-

Accepted Answer

Latent period

Answer

Median incubation period

Answer

Generation time

Answer

Serial interval

Question 4

WER stands for

Accepted Answer

Weekly epidemiological record

Answer

World epidemic record

Answer

Weekly environmental record

Answer

World epidemiological record

Question 5

Disease highly transmitted during incubation period is -

Accepted Answer

Chickenpox

Answer

Pertussis

Answer

Cholera

Answer

Measles

Answer

Brucellosis

Question 6

Population of a village on 1st January is 16,500. Since 1st January, 22 new cases of TB were detected during the year. Total registered cases were 220. What is the incidence of TB?

Accepted Answer

133 per 100,000

Answer

100 per 100,000

Answer

121 per 100,000

Answer

111 per 100,000

Question 7

"Tracking" of blood pressure means:

Accepted Answer

High blood pressures in children tend to perpetuate in adults

Answer

Controlling high BP with nifedipine

Answer

Pictorial representation of serial blood pressures of an individual

Answer

None of the options

Question 8

In the International death certificate one of the following is not true -

Accepted Answer

Part I of the certificate deals with the immediate cause only

Answer

Part I of the certificate deals with the immediate cause and also the underlying cause

Answer

Part II records significantly associated diseases

Answer

The certificate has been recommended by the WHO for international comparability

Question 9

What happens in disease elimination:

Accepted Answer

Interruption of disease transmission from large geographical areas

Answer

Global eradication of disease agent

Answer

Incidence is reduced by 10%

Answer

Prevalence is reduced by 10%

Question 10

An influenza pandemic is defined as:

Accepted Answer

A worldwide epidemic of influenza caused by a new virus strain

Answer

A localized outbreak of seasonal influenza

Answer

An annual recurrence of influenza in winter months

Answer

A gradual increase in influenza cases over several years

Epidemiology — MCQs

Epidemiology — MCQs

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