NEET-PG 2013 - Community Medicine Practice Questions

Q: Infectivity period of chickenpox is ?

1 day before and 4 days after appearance of rash. ***1 day before and 4 days after appearance of rash*** - The infectivity period of **chickenpox (varicella)** begins approximately **1-2 days (24-48 hours) before the rash appears**. - It extends until **all lesions have crusted over**, which typically occurs around **5-6 days after rash onset**, though some sources cite **4-5 days**. - This option represents the **commonly accepted timeframe** taught in Indian medical curricula and NEET PG examinations. *4 days before and 5 days after appearance of rash* - The **pre-rash infectivity period is too long** in this option; chickenpox is infectious for only **1-2 days before rash**, not 4 days. - While the "5 days after" is medically accurate, the incorrect pre-rash duration makes this option wrong. *Only when scab falls* - This statement is **incorrect**; infectivity starts much earlier, **1-2 days before the rash appears**. - By the time scabs fall, the person is **no longer infectious**, as crusted lesions contain non-infectious material. - This option ignores the critical **pre-rash and early rash infectious period**. *Entire incubation period* - The **incubation period** for chickenpox is usually **10-21 days**, during which the individual is **not infectious** for most of this time. - Infectivity begins only in the **last 1-2 days of incubation** (just before rash onset) and continues into the eruptive phase, not for the entire duration.

Q: Which of the following is the primary component of the AFP (Acute Flaccid Paralysis) case definition used in polio surveillance?

Onset of acute flaccid paralysis. ***Onset of acute flaccid paralysis*** - The primary component of the **AFP case definition** for polio surveillance is the acute onset of **flaccid paralysis** in a child under 15 years, or paralytic illness in a person of any age when polio is suspected. - This definition is crucial for identifying all potential cases of polio, regardless of the cause, to ensure thorough investigation and prevent outbreaks. *Stool specimen positive for poliovirus* - A positive stool specimen for poliovirus is a **laboratory confirmation** of polio infection, but it is not the primary component of the initial case definition. - The AFP case definition aims for **high sensitivity** to capture all possible cases for investigation, even before laboratory results are available. *Presence of residual paralysis after 60 days* - Residual paralysis after 60 days is an important indicator for **classifying a confirmed polio case** and understanding the long-term impact. - However, it is a **follow-up criterion** used after the initial detection of AFP, not the primary component that triggers the initial surveillance. *All of the above* - While laboratory confirmation and residual paralysis provide further information about a case, the **initial identification relies specifically on the clinical presentation** of acute flaccid paralysis. - The broad clinical definition ensures that no potential polio case is missed, initiating an immediate public health response.

Q: Which of the following is NOT a criterion for defining a polio epidemic?

Cases occurring during a 6 month period. ***Correct: Cases occurring during a 6 month period*** - The definition of a polio epidemic primarily focuses on criteria like the number of cases, their geographical proximity, and the viral serotype causing the infection, not a specific duration of time over which cases occur. - While an outbreak naturally unfolds over a period, a fixed 6-month window is **not a formal defining criterion** for an epidemic, which typically emphasizes a sudden, significant increase above expected levels. *Incorrect: 2 or more cases* - An epidemic is generally defined by an **unusual increase in disease incidence**, and even two confirmed cases, especially in areas with low endemicity or where polio is eradicated, can signal an outbreak. - The presence of **two or more paralytic polio cases** within a specific area is often considered a critical threshold for declaring an epidemic, particularly for **wild poliovirus**. *Incorrect: Cases should occur in same locality* - For an epidemic to be declared, the cases must be **geographically linked** to indicate a common source or local transmission. - Cases spread across different, unconnected regions would suggest **sporadic occurrences** rather than a localized epidemic. *Incorrect: Caused by same virus type* - An epidemic implies a **common etiologic agent**, meaning the cases should be linked to the same serotype of **poliovirus** (e.g., wild poliovirus type 1). - If cases are caused by different serotypes, it indicates **multiple independent introductions** rather than a single epidemic outbreak.

Q: In typhoid, a person is considered a permanent carrier if they excrete bacilli for more than how many months?

1 year. **1 year** - A person is defined as a permanent carrier of typhoid if they excrete **Salmonella Typhi** in their feces or urine for **more than one year** after the acute illness. - This long-term excretion is often associated with chronic infection of the **gallbladder**, particularly in individuals with gallstones. - The definition of chronic/permanent carrier status is set at **≥12 months** of continuous bacillary excretion. *3 months* - Excreting bacilli for 3 months after acute typhoid is considered a **convalescent carrier state**, not a permanent one. - Many individuals clear the infection within this timeframe without becoming chronic carriers. *6 months* - While prolonged, 6 months of excretion still falls under the definition of a **convalescent or temporary carrier**, rather than a permanent carrier. - The threshold for "permanent" or "chronic" carrier status is typically set at 12 months. *3 years* - While a person excreting bacilli for 3 years would certainly be a permanent carrier, the established definition for permanent carrier status is met at **1 year**, not 3 years. - This option represents an unnecessarily longer duration than the standard definition.

Q: Malaria is transmitted in Rural areas by?

Anopheles culicifacies. ***Anopheles culicifacies*** - **_Anopheles culicifacies_** is the **primary vector of malaria in rural areas of India** and is also found in Southeast Asia. - Its breeding habitats often include **rice fields, irrigation channels, and temporary water collections** common in rural agricultural settings. - It accounts for a major proportion of rural malaria transmission in the Indian subcontinent. *Anopheles stephensi* - **_Anopheles stephensi_** is a significant malaria vector primarily found in **urban and semi-urban areas**, including parts of the Middle East, India, and Iran. - Its preferred breeding sites are **artificial containers found in urban environments**, such as water storage tanks, overhead tanks, and cisterns. *Anopheles dirus* - **_Anopheles dirus_** is a dominant malaria vector in **forested and hilly regions of Southeast Asia**, often associated with forest malaria. - It's known for outdoor feeding behavior and maintaining transmission in relatively undisturbed natural environments. *None of the options* - This option is incorrect because **_Anopheles culicifacies_** is a well-established and significant vector for malaria in rural areas of India. - Identification of a specific primary vector for rural transmission makes this choice invalid.

Q: What is the most common Anopheles mosquito responsible for malaria in India?

Anopheles culicifacies. ***Anopheles culicifacies*** - This species is the **most common and primary malaria vector in India**, responsible for approximately 60-70% of all malaria transmission in the country. - It is the **major rural vector** of malaria, especially in agricultural areas, and transmits both *Plasmodium vivax* and *P. falciparum*. - Given that the majority of India's population resides in rural areas where malaria burden is highest, *A. culicifacies* is the most important vector overall. *Anopheles stephensi* - This species is recognized as the **primary urban vector** of malaria in India, particularly for *P. vivax* and *P. falciparum*. - Its ability to breed in artificial containers makes it well-adapted to urban environments, but it accounts for a smaller proportion of total malaria cases compared to *A. culicifacies*. *Anopheles fluviatilis* - This species is an **important vector in hilly and forest areas** of India, rather than being the most common overall. - It is known to transmit both *P. vivax* and *P. falciparum* in these specific ecological niches. *Anopheles subpictus* - While present in India, *A. subpictus* is generally considered a **poor vector** of malaria due to its low susceptibility to Plasmodium infection. - It mainly breeds in diverse habitats including paddy fields and brackish water.

Q: Which indicator best measures the operational efficiency of a malaria control programme?

Annual blood examination rate. ***Annual blood examination rate*** - The **Annual Blood Examination Rate (ABER)** directly reflects the proportion of the population that has been tested for malaria, indicating the reach and effectiveness of surveillance activities. - A high ABER suggests that active case detection and diagnosis are being effectively implemented, which is crucial for operational efficiency in identifying and managing cases. *Infant parasite rate* - The **infant parasite rate** measures the prevalence of malaria infection among infants, serving as an indicator of recent transmission intensity. - While important for assessing disease burden and transmission, it doesn't directly measure the operational effectiveness of interventions like testing or treatment programs. *Slide positivity rate* - The **slide positivity rate (SPR)** is the proportion of positive malaria slides among all slides examined, indicating the likelihood of an individual seeking testing to actually have malaria. - While SPR helps understand disease activity among tested individuals, it doesn't reflect the full operational reach of a program in the general population or the overall testing effort. *Mosquito bite rate* - The **mosquito bite rate** measures the number of mosquito bites per person per night, indicating the level of human exposure to malaria vectors. - This is an entomological indicator of transmission risk and the impact of vector control, but it does not directly assess the operational efficiency of human-centric interventions like diagnosis and treatment programs.

Q: The international quarantine period for yellow fever as approved by the Government of India is ?

6 days. ***6 days*** - The **incubation period** for yellow fever is typically 3-6 days, and the 6-day quarantine period is internationally accepted to cover this range. - This period is established to prevent the importation and spread of the disease by ensuring that individuals arriving from endemic areas do not develop symptoms after arrival. *9 days* - This duration is **longer than the internationally recognized incubation period** for yellow fever and is not the standard quarantine period. - Implementing a 9-day quarantine would be excessive and not based on the typical disease progression. *10 days* - A 10-day quarantine period is also **not the standard** for yellow fever as approved by international health regulations or by the Government of India. - While some diseases may require a 10-day quarantine, yellow fever's incubation period makes 6 days sufficient. *12 days* - A 12-day quarantine is **significantly longer** than necessary for yellow fever, as virtually all cases would manifest symptoms within the first 6 days. - This period is typically associated with diseases with much longer incubation periods, which is not the case for yellow fever.

Q: Based on the type of life cycle, zoonoses are classified into all of the following except -

Anthropozoonoses. ***Anthropozoonoses*** - This is **NOT a life cycle-based classification** of zoonoses. - It describes the **direction of transmission** (animals to humans), not the complexity or types of hosts required in the parasite's life cycle. - While a valid classification of zoonoses, it is based on **transmission pattern**, not life cycle characteristics. *Cyclo-zoonoses* - These are zoonoses that require **more than one vertebrate host species** to complete their life cycle, but **no invertebrate host** is involved. - This IS a life cycle-based classification. - Examples include **taeniasis** (tapeworm infections) where the parasite cycles between humans and livestock. *Meta-zoonoses* - These zoonoses require **both vertebrate and invertebrate hosts** to complete their life cycle. - This IS a life cycle-based classification. - The **invertebrate host** acts as an essential part of the life cycle for maturation or multiplication of the pathogen (e.g., **arboviruses** transmitted by mosquitoes, **plague** via fleas). *Sporozoonoses* - While this term is **not part of the standard WHO classification** of zoonoses by life cycle, the prefix "sporo-" refers to **spore-forming stages** in parasitic life cycles. - The standard WHO classification includes: **Orthozoonoses** (direct), **Cyclozoonoses**, **Metazoonoses**, and **Saprozoonoses** (requiring inanimate environment). - However, this term relates to life cycle characteristics (spore stages), not transmission direction.

Question 1

Infectivity period of chickenpox is ?

Accepted Answer

1 day before and 4 days after appearance of rash

Answer

Only when scab falls

Answer

Entire incubation period

Answer

4 days before and 5 days after appearance of rash

Question 2

Which of the following is the primary component of the AFP (Acute Flaccid Paralysis) case definition used in polio surveillance?

Accepted Answer

Onset of acute flaccid paralysis

Answer

All of the above

Answer

Stool specimen positive for poliovirus

Answer

Presence of residual paralysis after 60 days

Question 3

Which of the following is NOT a criterion for defining a polio epidemic?

Accepted Answer

Cases occurring during a 6 month period

Answer

Caused by same virus type

Answer

Cases should occur in same locality

Answer

2 or more cases

Question 4

In typhoid, a person is considered a permanent carrier if they excrete bacilli for more than how many months?

Accepted Answer

1 year

Answer

3 months

Answer

6 months

Answer

3 years

Question 5

Malaria is transmitted in Rural areas by?

Accepted Answer

Anopheles culicifacies

Answer

Anopheles stephensi

Answer

Anopheles dirus

Answer

None of the options

Question 6

What is the most common Anopheles mosquito responsible for malaria in India?

Accepted Answer

Anopheles culicifacies

Answer

Anopheles stephensi

Answer

Anopheles subpictus

Answer

Anopheles fluviatilis

Question 7

Which indicator best measures the operational efficiency of a malaria control programme?

Accepted Answer

Annual blood examination rate

Answer

Infant parasite rate

Answer

Slide positivity rate

Answer

Mosquito bite rate

Question 8

All are features of yellow fever except?

Accepted Answer

Validity of vaccination begins immediately after vaccination

Answer

Caused by vector aedes

Answer

IP 3-6 days

Answer

1 attack gives life long immunity

Question 9

The international quarantine period for yellow fever as approved by the Government of India is ?

Accepted Answer

6 days

Answer

9 days

Answer

10 days

Answer

12 days

Question 10

Based on the type of life cycle, zoonoses are classified into all of the following except -

Accepted Answer

Anthropozoonoses

Answer

Cyclo-zoonoses

Answer

Sporozoonoses

Answer

Meta-zoonoses

NEET-PG 2013 — Community Medicine