Community Medicine
5 questionsIn which of the following diseases is mass vaccination considered ineffective?
What is the term for the time between infection and maximum infectivity?
Which method is primarily used to assess HIV prevalence?
What is the most common cancer diagnosed in men?
Which of the following statements about the population pyramid of India is incorrect?
NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs
Question 621: In which of the following diseases is mass vaccination considered ineffective?
- A. Tetanus (Correct Answer)
- B. None of the options
- C. Measles
- D. Polio
Explanation: ***Correct: Tetanus*** - Mass vaccination is considered **ineffective** for tetanus because it is **not a communicable disease** transmitted person-to-person - Tetanus is caused by **Clostridium tetani** spores present in soil and environment - Since there is **no herd immunity** benefit, vaccinating large populations simultaneously does not break any chain of transmission - **Individual immunization** with tetanus toxoid is highly effective for personal protection, but this is different from mass vaccination strategies used for communicable diseases - The focus for tetanus prevention is on **universal immunization** and **wound management**, not mass campaigns *Incorrect: Measles* - Mass vaccination for measles is **highly effective** due to its person-to-person transmission - Achieving high vaccination coverage (>95%) provides **herd immunity** and can lead to **elimination** - The **MMR vaccine** is a cornerstone of mass immunization programs worldwide *Incorrect: Polio* - Mass vaccination campaigns (Pulse Polio) have been **extremely effective** in nearly eradicating polio globally - The disease spreads through the fecal-oral route, making mass vaccination crucial for breaking transmission chains - Both **OPV** and **IPV** provide individual and community protection through herd immunity *Incorrect: None of the options* - This is incorrect because tetanus is a clear example where mass vaccination strategy is ineffective due to lack of person-to-person transmission
Question 622: What is the term for the time between infection and maximum infectivity?
- A. Communicable period
- B. Generation time (Correct Answer)
- C. Incubation period
- D. Serial interval
Explanation: ***Generation time*** - This is the **time interval** between receipt of infection by a host and the moment of **maximum infectivity** of that same host. - It is a crucial parameter in epidemiology for understanding **disease transmission dynamics** and the speed at which an epidemic can spread. *Incubation period* - This refers to the time from **exposure to an infectious agent** until the **onset of symptoms**. - It does not directly account for the timing of viral shedding or peak infectivity. *Serial interval* - This is the time between **symptom onset in a primary case** and **symptom onset in a secondary case** it infects. - While related to transmission, it focuses on symptomatic presentation rather than peak infectivity. *Communicable period* - This is the time during which an infected individual is **capable of transmitting** the infectious agent to others. - It represents the entire duration of potential transmission, not specifically the peak infectivity.
Question 623: Which method is primarily used to assess HIV prevalence?
- A. Sentinel surveillance in high-risk populations (Correct Answer)
- B. Passive surveillance through reporting systems
- C. Disease registries for HIV patients
- D. Active case finding through outreach programs
Explanation: ***Sentinel surveillance in high-risk populations*** - **Sentinel surveillance** focuses on specific, well-defined groups, such as pregnant women or individuals attending STD clinics, to get a representative estimate of **HIV prevalence** in the broader community. - This method is particularly effective for diseases that are difficult to track through general population surveys due to stigma or low overall prevalence. *Passive surveillance through reporting systems* - **Passive surveillance** relies on healthcare providers voluntarily reporting cases, which often leads to **underreporting** and an incomplete picture of an epidemic's true scope. - It primarily captures known cases rather than estimating the overall **prevalence** within a population. *Disease registries for HIV patients* - **Disease registries** are valuable for tracking the natural history, treatment outcomes, and long-term trends among *diagnosed* individuals, but they do not capture undiagnosed cases, thus not accurately representing **prevalence**. - They provide data on incidence (new cases) and patient management but are less suited for estimating the total number of people living with the disease at a given time. *Active case finding through outreach programs* - **Active case finding** aims to identify new cases within specific communities, usually in response to an outbreak or in populations with known high risk. - While it identifies undiagnosed individuals, its primary goal is case identification and linkage to care, rather than providing a **statistically representative prevalence** estimate for an entire population.
Question 624: What is the most common cancer diagnosed in men?
- A. Bladder cancer
- B. Colorectal cancer
- C. Oral cancer (Correct Answer)
- D. Prostate cancer
Explanation: ***Oral cancer*** - **Oral cancer** is the most common cancer diagnosed in men in India, particularly cancers of the **lip, oral cavity, and oropharynx**. - India accounts for approximately **one-third of the global burden** of oral cancers. - Major risk factors include **tobacco chewing (gutka, pan masala, betel quid), smoking, and alcohol consumption**. - Early detection through **oral examination** and avoiding tobacco products are key preventive measures. *Prostate cancer* - While prostate cancer is the most common cancer in men in **Western populations**, it ranks **much lower in India** (typically 3rd-5th most common). - Incidence is increasing in urban Indian populations due to improved detection and lifestyle changes. *Bladder cancer* - **Bladder cancer** is significant but less common than oral cancer in Indian men. - Risk factors include **smoking** and occupational exposure to chemicals. *Colorectal cancer* - **Colorectal cancer** is increasing in incidence in India but remains less common than oral cancer in men. - Screening with **colonoscopy** is recommended for early detection, especially in those with family history.
Question 625: Which of the following statements about the population pyramid of India is incorrect?
- A. India has narrow apex
- B. Developing countries have bulge in the center
- C. India has narrow base (Correct Answer)
- D. India has broad base
Explanation: ***Correct Answer: India has narrow base*** - A **narrow base** in a population pyramid indicates a **low birth rate** and a small proportion of young people. - This statement is **INCORRECT for India**, as India's population pyramid has a **broad base** due to high birth rates and a large proportion of children and young people. - This is the correct answer because the question asks for the incorrect statement. *Incorrect Option: India has narrow apex* - A **narrow apex** signifies a **smaller proportion of older individuals**, indicating lower life expectancy. - This is TRUE for India's population pyramid, making it an incorrect answer choice. *Incorrect Option: Developing countries have bulge in the center* - A **bulge in the center** represents a larger cohort of working-age adults in developing countries undergoing demographic transition. - This reflects improvements in childhood survival and declining (but still substantial) birth rates. - This is TRUE, making it an incorrect answer choice. *Incorrect Option: India has broad base* - A **broad base** indicates a **high birth rate** and large proportion of young children in the population. - This is TRUE and characteristic of India's population structure, making it an incorrect answer choice.
Microbiology
1 questionsWhich disease is classified as 'multibacillary'?
NEET-PG 2012 - Microbiology NEET-PG Practice Questions and MCQs
Question 621: Which disease is classified as 'multibacillary'?
- A. Leprosy (Correct Answer)
- B. Tuberculosis
- C. Trachoma
- D. Tetanus
Explanation: **Leprosy** - Leprosy, caused by *Mycobacterium leprae*, is classified by the **WHO** into **paucibacillary (PB)** and **multibacillary (MB)** forms based on bacterial load and number of skin lesions. - **Multibacillary leprosy** is defined as having more than 5 skin lesions with positive skin smears, requiring a longer treatment regimen (12 months of multidrug therapy with rifampicin, dapsone, and clofazimine). - This classification is specific to **leprosy** and is crucial for determining appropriate treatment duration and drug combinations. *Tuberculosis* - Tuberculosis is classified by **anatomical location** (pulmonary vs. extrapulmonary), **drug susceptibility** (drug-sensitive vs. drug-resistant), or **smear status** (smear-positive vs. smear-negative). - The term **'multibacillary'** is not used in TB classification, making this an incorrect option. *Trachoma* - Trachoma is a chronic **keratoconjunctivitis** caused by *Chlamydia trachomatis*, classified by **clinical stages** (TF, TI, TS, TT, CO) according to the WHO simplified grading system. - The paucibacillary/multibacillary classification does **not apply** to trachoma. *Tetanus* - Tetanus is a **toxin-mediated disease** caused by *Clostridium tetani*, manifesting as muscle spasms and lockjaw. - Classification is based on **clinical severity** (localized, generalized, cephalic, neonatal), not bacterial load, making the term 'multibacillary' inapplicable.
Obstetrics and Gynecology
1 questionsWhich contraceptive method has the lowest pregnancy failure rate (typical use)?
NEET-PG 2012 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 621: Which contraceptive method has the lowest pregnancy failure rate (typical use)?
- A. Diaphragm
- B. Condom
- C. Intrauterine Contraceptive Device (IUCD) (Correct Answer)
- D. Oral Contraceptive Pills (OCP)
Explanation: ***Intrauterine Contraceptive Device (IUCD)*** - **IUCDs** are highly effective, with a **pregnancy failure rate of less than 1%** in typical use due to their long-acting and reversible nature, requiring no daily action from the user. - They are **fit-and-forget methods**, eliminating user error inherent in other forms of contraception, leading to very low typical use failure rates. *Diaphragm* - The **diaphragm** has a significantly higher typical use failure rate (around 12-16%) because its effectiveness depends on **correct placement** and consistent use with spermicide before each intercourse. - It is a **user-dependent method**, making its efficacy susceptible to improper use or non-use during sexual activity. *Condom* - **Condoms** have a typical use failure rate of about 13-18%, largely due to **incorrect use**, breakage, or slippage. - Their effectiveness relies heavily on **consistent and proper application** with every act of intercourse. *Oral Contraceptive Pills (OCP)* - **Oral Contraceptive Pills (OCPs)** have a typical use failure rate of approximately 7-9%, primarily because effectiveness is dependent on **daily adherence** at roughly the same time. - **Missed pills** are a common reason for failure, significantly increasing the risk of pregnancy compared to methods that do not require daily action.
Ophthalmology
1 questionsWhat is the most common protozoan associated with keratitis?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 621: What is the most common protozoan associated with keratitis?
- A. Plasmodium
- B. Acanthamoeba (Correct Answer)
- C. Toxoplasma
- D. Entamoeba histolytica
Explanation: ***Acanthamoeba*** - **Acanthamoeba keratitis** is a serious and painful infection of the eye's cornea, most commonly associated with **contact lens wearers** who do not properly disinfect their lenses. - The organism is a **free-living protozoan** found in soil and water. *Plasmodium* - **Plasmodium** species are the causative agents of **malaria**, a disease that primarily affects **red blood cells** and the liver. - While it can manifest with ocular symptoms like **retinopathy**, it does not typically cause **keratitis**. *Toxoplasma* - **Toxoplasma gondii** causes **toxoplasmosis**, an infection that can lead to **chorioretinitis** (inflammation of the retina and choroid), especially in immunocompromised individuals or congenitally infected infants. - It does not directly cause **keratitis** as its primary ocular manifestation. *Entamoeba histolytica* - **Entamoeba histolytica** is the protozoan responsible for **amebiasis**, particularly **amoebic dysentery** and **liver abscesses**. - Ocular involvement with *Entamoeba histolytica* is extremely rare and typically involves **metastatic lesions** to the orbit or eyelids, not directly primary keratitis.
Pharmacology
2 questionsAs per RNTCP guidelines, Multi drug resistance (MDR) TB is defined as resistance to:
Which of the following is the mechanism of action of tetanospasmin ?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 621: As per RNTCP guidelines, Multi drug resistance (MDR) TB is defined as resistance to:
- A. Rifampicin
- B. Rifampicin, isoniazid and ethambutol
- C. None of the above
- D. Rifampicin and isoniazid (Correct Answer)
Explanation: ***Rifampicin and isoniazid*** - According to **RNTCP guidelines** (now NTEP), **MDR-TB** is specifically defined as tuberculosis that is resistant to at least both **rifampicin** and **isoniazid**. - These two drugs are the **most potent first-line anti-TB medications**, and resistance to both significantly complicates treatment. *Rifampicin* - While resistance to **rifampicin alone** is a serious concern, it is classified as **rifampicin-resistant TB (RR-TB)**, not full **MDR-TB**. - **MDR-TB** requires resistance to at least two key first-line drugs. *Rifampicin, isoniazid and ethambutol* - Resistance to **rifampicin**, **isoniazid**, and **ethambutol** would be a form of **MDR-TB** (as it includes resistance to rifampicin and isoniazid), but it is a more extensive form of resistance. - The minimum definition of **MDR-TB** focuses on the two most crucial first-line drugs. *None of the above* - This option is incorrect because there is a specific definition for **MDR-TB** that aligns with one of the provided choices. - The guidelines clearly define **MDR-TB** based on resistance to specific drugs.
Question 622: Which of the following is the mechanism of action of tetanospasmin ?
- A. Inhibition of release of GABA and glycine (Correct Answer)
- B. Inhibition of Ach release from synapse
- C. Inhibition of protein synthesis
- D. Activation of adenylyl cyclase
Explanation: ***Inhibition of release of GABA and glycine*** - **Tetanospasmin** is a potent neurotoxin produced by *Clostridium tetani* that acts by blocking the release of inhibitory neurotransmitters, specifically **GABA (gamma-aminobutyric acid)** and **glycine**, from presynaptic terminals in the spinal cord and brainstem. - This inhibition leads to **uncontrolled muscle spasms**, rigidity, and convulsions, characteristic of tetanus, due to the lack of inhibitory signals to motor neurons. *Inhibition of Ach release from synapse* - This mechanism is characteristic of **botulinum toxin** (produced by *Clostridium botulinum*), not tetanospasmin. - Botulinum toxin inhibits the release of **acetylcholine (ACh)** at the neuromuscular junction, leading to flaccid paralysis. *Inhibition of protein synthesis* - This mechanism is associated with toxins like **diphtheria toxin** and **exotoxin A** from *Pseudomonas aeruginosa*. - These toxins inactivate elongation factor-2 (EF-2), thereby blocking protein synthesis and causing cell death. *Activation of adenylyl cyclase* - Toxins such as **cholera toxin** and **pertussis toxin** act by activating adenylyl cyclase, leading to an increase in intracellular cAMP levels. - This mechanism causes effects like severe diarrhea in cholera and respiratory symptoms in whooping cough.