Epidemiology Practice Questions

Q: Communicability of disease is assessed by

Secondary attack rate. ***Secondary attack rate*** - The **secondary attack rate** directly measures the proportion of susceptible individuals who become infected after exposure to a primary case within a household or other closed setting, making it a direct indicator of **communicability**. - It quantifies the spread of disease from an existing case to close contacts, specifically reflecting how easily a pathogen transmits. *Incubation period* - The **incubation period** is the time from exposure to a pathogen to symptom onset, which indicates the latency of disease, not its communicability. - While it helps in case tracing and surveillance, it doesn't directly measure how easily the disease spreads from one person to another. *Serial interval* - The **serial interval** is the time between symptom onset in an infected person and symptom onset in a person infected by them; it reflects the pace of an epidemic but doesn't quantify transmissibility. - While related to transmission dynamics, it's not a direct measure of how likely an exposed person is to get sick. *Generation time* - **Generation time** is the average time between infection in a primary case and infection in a secondary case, providing a measure of the pathogen's intrinsic rate of spread. - It is similar to serial interval but focuses on infection times rather than symptom onset, and like the serial interval, it contributes to understanding disease dynamics but isn't as direct a measure of communicability as the secondary attack rate.

Q: All of the following are components of primordial prevention EXCEPT

Immunization. ***Immunization*** - **Immunization** is a component of **primary prevention**, aiming to prevent the onset of disease in healthy individuals. - Primordial prevention focuses on preventing the establishment of risk factors themselves, rather than preventing the disease directly. *Behavioural changes* - **Behavioural changes**, such as encouraging healthy lifestyles from a young age, are central to primordial prevention. - The goal is to prevent the adoption of unhealthy behaviours that could lead to disease later in life. *Health education* - **Health education**, particularly in early life stages, is a key strategy for primordial prevention. - It helps in fostering healthy habits and promoting awareness before risk factors emerge. *Nutritional education* - Providing **nutritional education** to prevent the development of poor dietary habits is a core aspect of primordial prevention. - This aims to prevent the establishment of risk factors like obesity and hypertension from an early age.

Q: ICD-10 chapter 1 describes?

Infectious and parasitic diseases. ***Infectious and parasitic diseases*** - **ICD-10 Chapter 1** specifically categorizes codes related to **infectious and parasitic diseases**, ranging from A00 to B99. - This chapter covers a broad spectrum of conditions caused by microorganisms and parasites, such as bacterial, viral, fungal, and protozoal infections. *Poisoning and consequences* - **Poisoning and certain other consequences of external causes** are covered in ICD-10 Chapter 19, with codes typically ranging from T36-T65 for poisoning by drugs, medicaments, and biological substances. - This chapter focuses on injuries, poisoning, and certain other consequences of external causes, not infectious diseases. *Psychiatric diseases* - **Mental and behavioral disorders** (often referred to as psychiatric diseases) are described in ICD-10 Chapter 5, with codes ranging from F00 to F99. - This chapter includes conditions such as mood disorders, anxiety disorders, schizophrenia, and substance-related disorders. *Diseases of the nervous system* - **Diseases of the nervous system** are categorized in ICD-10 Chapter 6, with codes ranging from G00 to G99. - This chapter covers conditions affecting the brain, spinal cord, nerves, and neuromuscular junctions, such as stroke, epilepsy, and Parkinson's disease.

Q: The disability adjusted life years (DALYs) lost due to neuropsychiatric disorders are highest in -

Unipolar depressive disorders. ***Unipolar depressive disorders*** - **Unipolar depressive disorders** are the leading cause of DALYs lost among neuropsychiatric conditions globally. - This is due to their **high prevalence**, **early age of onset**, and significant impact on **functional capacity** and quality of life. *Panic disorders* - While panic disorders significantly impair an individual's quality of life, their **prevalence** and **disability burden** are generally lower than that of unipolar depressive disorders. - They tend to cause episodic, intense distress rather than chronic, pervasive functional impairment to the same extent as severe depression. *Obsessive compulsive disorder* - **OCD** can be severely disabling, but its **prevalence** is lower than that of unipolar depressive disorders. - The impact on DALYs, while substantial for affected individuals, does not reach the global burden attributed to depression. *Bipolar affective disorders* - **Bipolar affective disorders** contribute significantly to DALYs due to their chronic nature and severe episodes of mood disturbance. - However, their **prevalence** is lower compared to unipolar depressive disorders, resulting in a lower overall DALY burden globally.

Q: Disease not under integrated disease surveillance project is?

Herpes Zoster. ***Herpes Zoster*** - **Herpes Zoster**, also known as shingles, is a viral disease that is typically not included in the list of diseases under routine surveillance by the Integrated Disease Surveillance Project (IDSP) in many regions. - The IDSP primarily focuses on diseases with **epidemic potential** or high public health impact for early detection and rapid response. *Meningoencephalitis* - **Meningoencephalitis** (inflammation of the brain and meninges) is a serious condition with epidemic potential, making it a key disease for surveillance under projects like IDSP. - Early detection of clusters can help prevent widespread outbreaks and manage severe neurological outcomes. *TB* - **Tuberculosis (TB)** is a major public health concern due to its high prevalence, chronic nature, and potential for transmission, especially drug-resistant forms. - It is consistently included in surveillance programs like IDSP for consistent monitoring, case finding, and treatment adherence. *Cholera* - **Cholera** is an acute diarrheal disease with high epidemic potential due to rapid transmission, particularly in areas with poor sanitation. - It is a critical disease for surveillance to enable quick identification of outbreaks, implementation of control measures, and prevention of mass fatalities.

Q: Quarantine duration is primarily based on:

Maximum incubation. ***Maximum incubation*** - Quarantine duration is set to cover the **maximum incubation period** of a disease to ensure that individuals who are infected but asymptomatic eventually develop symptoms and can be isolated. - This prevents potentially infected individuals from transmitting the disease to others after their isolation period ends. *Generation time* - **Generation time** is the average time between an individual becoming infected and that individual infecting others. - While related to transmission, it's not the primary determinant for the **maximum duration an asymptomatic person could be infectious** without showing symptoms, which is the focus of quarantine. *Serial interval* - The **serial interval** is the time between symptom onset in an infected person and symptom onset in a person they infect. - Like generation time, it describes the pace of an epidemic but doesn't define the **outer limit of when an infected person might show symptoms** to determine quarantine length. *Minimum incubation period* - The **minimum incubation period** is the shortest time between exposure and symptom onset. - Relying on the minimum incubation period would lead to a quarantine that is too short, as many individuals would still be in their **asymptomatic infectious phase** after quarantine ends.

Q: Incubation period of which disease is less than 7 days?

Cholera. ***Cholera*** - Cholera has a very short incubation period, typically ranging from **a few hours to 5 days**, often within 2 to 3 days. - This rapid onset is due to the quick action of **Vibrio cholerae toxin** on the intestinal lining. *Measles* - The incubation period for measles is generally **10 to 14 days** from exposure to the onset of fever. - The characteristic rash appears several days after the initial fever. *Mumps* - Mumps typically has an incubation period of **16 to 18 days**, with a range of 12 to 25 days. - This longer period precedes the onset of symptoms like fever and **parotid gland swelling**. *Leishmaniasis* - The incubation period for leishmaniasis can be highly variable, ranging from **weeks to months or even years**, depending on the species and form of the disease (visceral, cutaneous). - This lengthy period reflects the complex life cycle of the **Leishmania parasite** within the host.

Q: Incubation period of Salmonella typhi -

3-21 days. ***3-21 days*** - The typical incubation period for **Salmonella Typhi**, the bacterium causing typhoid fever, ranges from **3 to 21 days**. - This period allows the bacteria to multiply in the host before symptoms such as fever, headache, and malaise begin to appear. *2-5 days* - This incubation period is generally too short for **typhoid fever**, which typically has a longer course due to the pathogen's systemic spread. - Shorter incubation periods are more characteristic of other forms of **salmonellosis**, such as gastroenteritis. *14-25 days* - While overlap exists, a consistent range of **14 to 25 days** tends to skew towards the longer end of the typical incubation period, potentially missing earlier presentations. - The **3-21 day range** is more commonly cited in medical literature as the average window. *0-60 days* - An incubation period of **0-60 days** is excessively broad and lacks clinical precision for **typhoid fever**. - While rare cases might fall outside the typical range, this option includes an implausible immediate onset (0 days) and an overly protracted maximum duration.

Question 1

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

Question 2

Communicability of disease is assessed by

Accepted Answer

Secondary attack rate

Answer

Incubation period

Answer

Serial interval

Answer

Generation time

Question 3

All of the following are components of primordial prevention EXCEPT

Accepted Answer

Immunization

Answer

Behavioural changes

Answer

Health education

Answer

Nutritional education

Question 4

ICD-10 chapter 1 describes?

Accepted Answer

Infectious and parasitic diseases

Answer

Poisoning and consequences

Answer

Psychiatric diseases

Answer

Diseases of the nervous system

Question 5

The disability adjusted life years (DALYs) lost due to neuropsychiatric disorders are highest in -

Accepted Answer

Unipolar depressive disorders

Answer

Panic disorders

Answer

Obsessive compulsive disorder

Answer

Bipolar affective disorders

Question 6

Disease not under integrated disease surveillance project is?

Accepted Answer

Herpes Zoster

Answer

Meningoencephalitis

Answer

TB

Answer

Cholera

Question 7

Quarantine duration is primarily based on:

Accepted Answer

Maximum incubation

Answer

Generation time

Answer

Serial interval

Answer

Minimum incubation period

Question 8

Incubation period of which disease is less than 7 days?

Accepted Answer

Cholera

Answer

Measles

Answer

Mumps

Answer

Leishmaniasis

Question 9

Incubation period of Salmonella typhi -

Accepted Answer

3-21 days

Answer

2-5 days

Answer

14-25 days

Answer

0-60 days

Question 10

All of the following are true about the Herd immunity for infectious diseases except -

Accepted Answer

It is more easily achieved for infections that do not have a sub-clinical phase

Answer

In the case of tetanus it does not protect the individual

Answer

It is affected by the presence and distribution of alternative animal hosts

Answer

It refers to group protection beyond what is afforded by the protection of immunized individuals

Epidemiology — MCQs

Epidemiology — MCQs

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