Community Medicine
6 questionsInfectivity period of chickenpox is ?
Which of the following is the primary component of the AFP (Acute Flaccid Paralysis) case definition used in polio surveillance?
Which of the following is NOT a criterion for defining a polio epidemic?
In typhoid, a person is considered a permanent carrier if they excrete bacilli for more than how many months?
Malaria is transmitted in Rural areas by?
Which indicator best measures the operational efficiency of a malaria control programme?
NEET-PG 2013 - Community Medicine NEET-PG Practice Questions and MCQs
Question 531: Infectivity period of chickenpox is ?
- A. 1 day before and 4 days after appearance of rash (Correct Answer)
- B. Only when scab falls
- C. Entire incubation period
- D. 4 days before and 5 days after appearance of rash
Explanation: ***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.
Question 532: Which of the following is the primary component of the AFP (Acute Flaccid Paralysis) case definition used in polio surveillance?
- A. All of the above
- B. Stool specimen positive for poliovirus
- C. Onset of acute flaccid paralysis (Correct Answer)
- D. Presence of residual paralysis after 60 days
Explanation: ***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.
Question 533: Which of the following is NOT a criterion for defining a polio epidemic?
- A. Caused by same virus type
- B. Cases should occur in same locality
- C. 2 or more cases
- D. Cases occurring during a 6 month period (Correct Answer)
Explanation: ***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.
Question 534: In typhoid, a person is considered a permanent carrier if they excrete bacilli for more than how many months?
- A. 3 months
- B. 6 months
- C. 1 year (Correct Answer)
- D. 3 years
Explanation: **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.
Question 535: Malaria is transmitted in Rural areas by?
- A. Anopheles stephensi
- B. Anopheles dirus
- C. Anopheles culicifacies (Correct Answer)
- D. None of the options
Explanation: ***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.
Question 536: Which indicator best measures the operational efficiency of a malaria control programme?
- A. Infant parasite rate
- B. Slide positivity rate
- C. Mosquito bite rate
- D. Annual blood examination rate (Correct Answer)
Explanation: ***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.
Internal Medicine
2 questionsWhich of the following statements about polio is false?
Which of the following is NOT a symptom of mild dehydration?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 531: Which of the following statements about polio is false?
- A. 99% non paralytic
- B. Aseptic meningitis
- C. Flaccid paralysis
- D. Increased tendon reflexes (Correct Answer)
Explanation: ***Increased tendon reflexes*** - Polio causes **lower motor neuron damage**, specifically to the anterior horn cells of the spinal cord [1]. - This damage leads to **flaccid paralysis** and **decreased or absent deep tendon reflexes**, not increased reflexes [3]. *99% non paralytic* - The vast majority of poliovirus infections (approximately 95-99%) are **asymptomatic** or cause only mild, non-specific symptoms. - Only a small percentage of infected individuals develop the more severe paralytic form of the disease. *Flaccid paralysis* - Poliovirus directly attacks and destroys **motor neurons** in the anterior horn of the spinal cord [1]. - This damage results in **muscle weakness** and loss of muscle tone, leading to **flaccid paralysis** [3]. *Aseptic meningitis* - About 1-5% of poliovirus infections can manifest as **aseptic meningitis**, characterized by symptoms like fever, headache, neck stiffness, and vomiting without bacterial infection [2]. - This form of meningitis is typically **self-limiting** and does not lead to paralysis [2].
Question 532: Which of the following is NOT a symptom of mild dehydration?
- A. Thirst
- B. Restlessness
- C. Dry tongue
- D. Normal BP (Correct Answer)
Explanation: ***Normal BP*** - In **mild dehydration**, the body's compensatory mechanisms, such as increased heart rate and vasoconstriction, typically manage to maintain a **normal blood pressure**. [1] - A significant drop in **blood pressure** (hypotension) is usually indicative of **moderate to severe dehydration**, where these compensatory mechanisms begin to fail. [2] *Thirst* - **Thirst** is one of the **earliest and most reliable** indicators of dehydration, as the body signals a need for fluid intake. [3] - It arises in response to increased plasma osmolality and decreased blood volume, both occurring even in **mild dehydration**. [3] *Restlessness* - **Restlessness** can be an early sign of discomfort and altered mental status associated with **mild dehydration**, particularly in infants and young children. - As the body struggles to maintain fluid balance, individuals may experience irritability and general unease. *Dry tongue* - A **dry tongue** and **dry sticky mucous membranes** are common signs of mild to moderate dehydration. - This symptom results from reduced salivary production due to decreased fluid volume in the body.
Microbiology
2 questionsWhich staining method is specifically used for the detection of mycoplasma?
All are non-sporing anaerobes of medical importance except which of the following?
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 531: Which staining method is specifically used for the detection of mycoplasma?
- A. Dienes method (Correct Answer)
- B. Fontana method
- C. Lavaditi method
- D. No applicable method
Explanation: ***Dienes method*** - The **Dienes staining method** is a specialized procedure used specifically to identify **Mycoplasma colonies** grown on agar medium. - It works by staining the characteristic **fried-egg appearance** of Mycoplasma colonies. *Fontana method* - The Fontana method is a **silver impregnation stain** used primarily for the visualization of **spirochetes**, such as *Treponema pallidum*. - It is not suitable for detecting Mycoplasma due to their distinct cellular structure and size differences compared to spirochetes. *Lavaditi method* - The Lavaditi method is another type of **silver stain** developed for the detection of **spirochetes** in tissue sections. - Similar to the Fontana method, it is not appropriate for the identification of Mycoplasma. *No applicable method* - This statement is incorrect as the **Dienes method** is, in fact, specifically applicable and widely used for the detection and identification of Mycoplasma colonies. - There are established microbiological techniques for identifying Mycoplasma.
Question 532: All are non-sporing anaerobes of medical importance except which of the following?
- A. Bacteroides
- B. Fusobacterium
- C. Clostridia (Correct Answer)
- D. Actinomyces
Explanation: ***Clostridia*** - This genus is characterized by its ability to form **spores**, which are highly resistant structures allowing survival in adverse conditions. - Examples include *Clostridium difficile*, *Clostridium tetani*, and *Clostridium botulinum*, all of which are important human pathogens. *Actinomyces* - *Actinomyces* are **non-sporing, Gram-positive, anaerobic rods** that cause chronic, granulomatous infections, often forming sinus tracts. - They are known for producing characteristic **"sulfur granules"** in pus. *Bacteroides* - *Bacteroides* are **non-sporing, Gram-negative, anaerobic rods** that are a major component of the normal human gut flora. - They are frequently involved in **intra-abdominal infections** and abscess formation. *Fusobacterium* - *Fusobacterium* species are **non-sporing, Gram-negative, fusiform-shaped anaerobic rods**. - They are common in the **oral cavity** and can cause infections such as Vincent's angina and Lemierre's syndrome.