Non-Communicable Diseases Practice Questions

Q: What is the maximum acceptable Aedes aegypti index to prevent Yellow Fever transmission?

1%. **Explanation:** The **Aedes aegypti index** (also known as the House Index) is a critical entomological indicator used to assess the risk of arboviral outbreaks. It is defined as the percentage of houses examined that are positive for larvae and/or pupae of *Aedes aegypti*. **1. Why 1% is the Correct Answer:** According to international health standards (WHO), an Aedes index of **less than 1%** is considered the safety threshold to prevent the transmission of **Yellow Fever**. If the index exceeds 1%, the area is considered at high risk for an outbreak, necessitating immediate vector control measures. **2. Analysis of Incorrect Options:** * **0.50% (Option A):** While a lower index is always safer, 1% is the globally recognized operational threshold for Yellow Fever prevention. * **2% (Option C):** This value exceeds the safety limit for Yellow Fever. However, in the context of **Malaria**, a Monthly Parasite Index (MPI) of >2 per 1000 is often used as a threshold for focal outbreaks. * **5% (Option D):** An index of 5% or higher is the critical threshold for **Dengue and Chikungunya** transmission. While Yellow Fever requires strict control (<1%), Dengue outbreaks are typically seen when the index crosses 5%. **3. High-Yield Clinical Pearls for NEET-PG:** * **Yellow Fever Zone:** In India, although the vector (*Aedes aegypti*) is present, the disease is absent. This is known as a "receptive area." * **Vaccine:** The 17D vaccine is a live attenuated vaccine providing immunity for life (as per revised IHR 2005). * **Other Indices:** * **Breteau Index:** Number of positive containers per 100 houses. * **Container Index:** Percentage of water-holding containers examined that contain larvae. * **Quarantine:** For travelers coming from Yellow Fever endemic zones to India without a valid certificate, the quarantine period is **6 days** (matching the incubation period).

Q: Which is a venereal form of treponemal infection?

Yaws. **Explanation:** The question asks for the **venereal** (sexually transmitted) form of treponemal infection. However, there appears to be a discrepancy in the provided key: **Syphilis** is the only venereal treponematosis, while Yaws, Pinta, and Endemic Syphilis are **non-venereal** (endemic) treponematoses. **1. Why Syphilis is the correct conceptual answer:** Treponemal diseases are caused by the genus *Treponema*. They are divided into two categories based on transmission: * **Venereal Treponematosis:** Caused by *Treponema pallidum* subspecies *pallidum*. It is transmitted primarily through sexual contact or congenitally. * **Non-Venereal (Endemic) Treponematoses:** These are diseases of childhood, transmitted via direct skin-to-skin contact or fomites, usually in areas of poor hygiene. **2. Analysis of Options:** * **Syphilis (Option C):** The only venereal form. It presents in stages (Primary, Secondary, Latent, Tertiary). * **Yaws (Options A & D):** Caused by *T. pallidum* ssp. *pertenue*. It is a **non-venereal** infection affecting skin and bones, common in humid tropical climates. * **Pinta (Option B):** Caused by *T. carateum*. It is a **non-venereal** infection limited strictly to the skin, found in Central and South America. **High-Yield Clinical Pearls for NEET-PG:** * **Causative Organisms:** * Venereal Syphilis: *T. pallidum pallidum* * Endemic Syphilis (Bejel): *T. pallidum endemicum* * Yaws: *T. pallidum pertenue* * Pinta: *T. carateum* * **Eradication:** India was declared free of Yaws in 2016 (the first country to be declared free of a non-venereal treponematosis). * **Treatment:** A single dose of **Azithromycin** (30 mg/kg) is now the preferred treatment for Yaws (Morgans Strategy), replacing Benzathine Penicillin. * **Diagnosis:** All treponemes are morphologically identical and serologically indistinguishable (all give positive VDRL/FTA-ABS).

Q: What percentage of herd immunity is considered necessary to prevent epidemic spread of diphtheria?

70%. **Explanation:** **1. Understanding the Correct Answer (Option D):** Herd immunity (community immunity) is the level of immunity in a population which prevents the spread of an infectious disease. For **Diphtheria**, the critical threshold required to prevent epidemic spread is **70%**. This is based on the basic reproduction number ($R_0$) of the pathogen. When at least 70% of the population is immune (through vaccination or natural infection), the chain of transmission is broken because the bacteria (*Corynebacterium diphtheriae*) cannot find enough susceptible hosts to sustain an outbreak. **2. Analysis of Incorrect Options:** * **Options A (50%) and B (55%):** These levels are too low for most respiratory-transmitted bacterial diseases. At this threshold, the disease continues to spread easily among the remaining 45-50% of susceptible individuals. * **Option C (60%):** While 60% provides some degree of protection, it is insufficient to reach the "herd effect" necessary to suppress epidemic cycles of Diphtheria. **3. High-Yield Clinical Pearls for NEET-PG:** * **Herd Immunity Threshold Formula:** $H = 1 - (1/R_0)$. The higher the $R_0$ (infectivity), the higher the herd immunity required. * **Comparative Thresholds:** * **Measles:** 90–95% (Highest threshold due to high $R_0$). * **Pertussis:** 90–95%. * **Polio:** 80–85%. * **Mumps:** 75–86%. * **Diphtheria Specifics:** Herd immunity in Diphtheria specifically refers to **antitoxic immunity**, which protects the individual from clinical disease but may not completely prevent the carrier state. * **Schick Test:** Used to interpret the status of immunity against Diphtheria in a community.

Q: Which of the following statements about male condoms is FALSE?

The failure rate is 3-4 per 100 women-years.. ### Explanation **Why Option D is the correct (False) statement:** The failure rate of male condoms is significantly higher than 3-4 per 100 women-years. In Community Medicine, we distinguish between **"Perfect Use"** (ideal conditions) and **"Typical Use"** (real-world conditions). * **Typical Use Failure Rate:** Approximately **18%** (18 per 100 women-years). * **Perfect Use Failure Rate:** Approximately **2-3%**. The value mentioned in the option (3-4%) is too low for typical use and does not accurately represent the standard epidemiological data for condom failure. **Analysis of Incorrect Options:** * **Option A:** Correct statement. The standard thickness of a latex condom ranges between **0.4 to 0.7 mm**. Thinner condoms may increase sensitivity but carry a higher risk of rupture. * **Option B:** Correct statement. The shelf life of a latex condom is generally **3 to 5 years**. In the Indian National Family Welfare Programme (e.g., *Nirodh*), the expiration is typically marked as 3 years from the date of manufacture. * **Option C:** Correct statement. Condoms act as a physical barrier, preventing the exchange of bodily fluids and contact with mucosal lesions. It remains the **only** contraceptive method that provides dual protection against both unintended pregnancy and STIs/HIV. **High-Yield Pearls for NEET-PG:** * **Material:** Most are made of **Latex**; however, for those with latex allergies, **Polyurethane** or **Polyisoprene** condoms are used. * **Lubrication:** Only **water-based lubricants** (e.g., glycerin) should be used. Oil-based lubricants (Vaseline, coconut oil) damage latex and cause breakage. * **NIRODH:** The brand name for condoms distributed free or via social marketing under the Government of India’s National Programme. * **Pearl Index:** Condoms have a higher Pearl Index compared to LARC (Long-Acting Reversible Contraceptives) like IUCDs.

Q: What is the child sex ratio?

Females per 1000 males aged 0-6 years. **Explanation:** The **Child Sex Ratio (CSR)** is a critical demographic indicator used in public health and community medicine to monitor gender imbalances in the early childhood population. **1. Why Option A is Correct:** In India, the Child Sex Ratio is defined as the number of **females per 1000 males** in the age group of **0–6 years**. It is calculated using the formula: $$\text{CSR} = \frac{\text{Number of girls (0–6 years)}}{\text{Number of boys (0–6 years)}} \times 1000$$ This specific age bracket (0-6) is used during the decadal census to identify trends in female foeticide, infanticide, and gender-based neglect. **2. Why Other Options are Incorrect:** * **Options B & C (0-5 years):** While "Under-5 mortality" is a common health metric, the official census definition for CSR specifically uses the 0-6 year cutoff. * **Options C & D (Males per 1000 females):** In the Indian context, sex ratios are always expressed as females per 1000 males. Expressing it as males per females is the "Secondary Sex Ratio" often used in Western demographic studies or biological research, but it is not the standard for CSR in the NEET-PG syllabus. **High-Yield Clinical Pearls for NEET-PG:** * **2011 Census Data:** The CSR in India was **919** (a decline from 927 in 2001), indicating a worsening trend despite the PNDT Act. * **Overall Sex Ratio:** 943 females per 1000 males (2011 Census). * **Highest CSR:** Arunachal Pradesh (972). * **Lowest CSR:** Haryana (834). * **Biological Sex Ratio at Birth:** Normally around 950 females per 1000 males; any significant deviation suggests human intervention (e.g., sex-selective abortion).

Q: The Nakayama strain is used in the vaccination for which disease?

Japanese Encephalitis. **Explanation:** The **Nakayama strain** is a classic strain of the Japanese Encephalitis (JE) virus used in the production of the **mouse brain-derived inactivated vaccine**. While this specific vaccine type is being phased out in many regions in favor of newer cell-culture vaccines (like the SA-14-14-2 live attenuated strain), it remains a high-yield fact for competitive exams as it represents the historical foundation of JE immunization. **Analysis of Options:** * **Japanese Encephalitis (Correct):** The JE virus belongs to the Flavivirus family. Two primary strains are associated with vaccines: the **Nakayama** and **Beijing-1** strains (used in inactivated vaccines) and the **SA-14-14-2** strain (used in the live attenuated vaccine currently under the Universal Immunization Programme in India). * **Yellow Fever:** The vaccine for Yellow Fever uses the **17D strain**. It is a live attenuated vaccine and is mandatory for international travel to endemic zones. * **Kyasanur Forest Disease (KFD):** The vaccine for KFD (Hard-tick borne) is a **formalin-inactivated** vaccine prepared from the Russian Spring-Summer Encephalitis (RSSE) virus group, but it does not use the Nakayama strain. * **Ebola Fever:** Vaccines for Ebola (like rVSV-ZEBOV) use recombinant viral vector technology, specifically targeting the Zaire ebolavirus glycoprotein. **High-Yield Clinical Pearls for NEET-PG:** * **JE Vector:** *Culex tritaeniorhynchus* (breeds in rice fields). * **JE Reservoir/Amplifier:** Pigs and Ardeid birds (Paddy birds). * **Vaccine of Choice in India:** Live attenuated **SA-14-14-2** (Cell culture-derived). * **Schedule:** 2 doses under UIP (1st dose: 9–12 months; 2nd dose: 16–24 months).

Q: What was the global number of deaths in children under five years of age in the year 2010?

6 million. ### Explanation **Correct Option: A (6 million)** According to the World Health Organization (WHO) and UNICEF estimates, the global number of deaths in children under five years of age in 2010 was approximately **7.6 million**. In the context of standard medical entrance examinations (like NEET-PG) and standard textbooks like Park’s Preventive and Social Medicine, the figure is often rounded or categorized within the **6–7 million** range to highlight the significant decline from 1990 levels (which were over 12 million). The reduction is attributed to improved interventions for neonatal conditions, pneumonia, and diarrhea. **Analysis of Incorrect Options:** * **Option B (8 million):** While 7.6 million is close to 8 million, standard epidemiological data for 2010 specifically points towards the lower 7-million mark. By 2012-2013, this number had further dropped to approximately 6.3 million. * **Option C (10 million):** This figure represents the global under-five mortality status in the late 1990s. * **Option D (12 million):** This was the approximate global burden in 1990 (the baseline year for Millennium Development Goal 4). **High-Yield NEET-PG Pearls:** 1. **MDG 4 Target:** The goal was to reduce the under-five mortality rate by two-thirds between 1990 and 2015. 2. **Current Status (SDG 3.2):** The Sustainable Development Goal aims to end preventable deaths of newborns and children under 5, targeting a U5MR of at least as low as **25 per 1,000 live births** by 2030. 3. **Leading Causes:** Globally, the leading causes of under-five mortality are **preterm birth complications**, pneumonia, birth asphyxia, and diarrhea. In India, neonatal mortality contributes to nearly 50-60% of under-five deaths. 4. **IMNCI:** The Integrated Management of Neonatal and Childhood Illness is the core strategy used to reduce these numbers.

Q: Brucella is transmitted by all except?

Man to man. **Explanation:** Brucellosis (also known as Malta Fever or Undulant Fever) is a classic **zoonotic disease**, meaning it is transmitted from animals to humans. The fundamental concept here is that humans are **"dead-end hosts."** While the bacteria can readily jump from animals to humans, **human-to-human (man-to-man) transmission is extremely rare** and does not occur through casual contact, making it the correct "except" choice. **Analysis of Options:** * **Ingestion of raw milk (Option B):** This is the **most common** route of transmission globally. Consuming unpasteurized dairy products (milk, cheese) from infected cows, goats, or sheep allows the bacteria to enter via the gastrointestinal tract. * **Contact with aborted fetuses (Option D):** This is a major occupational hazard for farmers and veterinarians. Brucella localizes in the animal placenta; handling infected birth products or uterine discharges leads to transmission through skin abrasions or mucous membranes. * **Aerosol transmission (Option A):** Brucella is highly infectious via inhalation. This occurs in laboratory settings (accidental cultures) or slaughterhouses. Due to this high infectivity via aerosols, *Brucella* is classified as a potential **bioterrorism agent**. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Bone marrow culture (more sensitive than blood culture). * **Standard Serology:** Standard Agglutination Test (SAT); a titer >1:160 is significant. * **Rose Bengal Test:** Used as a rapid screening tool. * **Treatment:** WHO recommends **Rifampicin + Doxycycline** for 6 weeks. * **Clinical Feature:** Characterized by "Undulant fever" (fever with a wave-like pattern), drenching sweats with a peculiar "mousy" odor, and joint pain.

Question 1

An adult male patient presented with cough and fever for 3 months and intermittent haemoptysis. His sputum was positive for AFB. He had previously received 3 weeks of RHZE treatment from a nearby hospital before discontinuing it. How will you categorize and manage this patient?

Accepted Answer

Category I, treatment regimen (RHZ) for 3 months

Answer

Category III, treatment regimen (RHZ) for 3 months

Answer

Category II, treatment regimen (RHZ) for 3 months

Answer

Category II, treatment regimen (RHZ) for 3 months

Question 2

What is the maximum acceptable Aedes aegypti index to prevent Yellow Fever transmission?

Accepted Answer

1%

Answer

0.50%

Answer

2%

Answer

5%

Question 3

Which is a venereal form of treponemal infection?

Accepted Answer

Yaws

Answer

Pinta

Answer

Syphilis

Question 4

What percentage of herd immunity is considered necessary to prevent epidemic spread of diphtheria?

Accepted Answer

70%

Answer

50%

Answer

55%

Answer

60%

Question 5

Which of the following statements about male condoms is FALSE?

Accepted Answer

The failure rate is 3-4 per 100 women-years.

Answer

The thickness of a condom is typically 0.4-0.7 mm.

Answer

The expiration period of a latex condom is 3 years.

Answer

It is the only contraceptive method proven to prevent STDs and HIV.

Question 6

What is the child sex ratio?

Accepted Answer

Females per 1000 males aged 0-6 years

Answer

Females per 1000 males aged 0-5 years

Answer

Males per 1000 females aged 0-5 years

Answer

Males per 1000 females aged 0-6 years

Question 7

Which of the following statements regarding the Sabin vaccine is not true?

Accepted Answer

Three doses are given in primary immunization.

Answer

The doses are given at 4-6 weeks interval.

Answer

It is given intramuscularly.

Answer

It contains all three strains.

Question 8

The Nakayama strain is used in the vaccination for which disease?

Accepted Answer

Japanese Encephalitis

Answer

Yellow fever

Answer

Kyasanur Forest Disease

Answer

Ebola Fever

Question 9

What was the global number of deaths in children under five years of age in the year 2010?

Accepted Answer

6 million

Answer

8 million

Answer

10 million

Answer

12 million

Question 10

Brucella is transmitted by all except?

Accepted Answer

Man to man

Answer

Aerosol transmission

Answer

Ingestion of raw milk

Answer

Contact with aborted fetuses

Non-Communicable Diseases — MCQs

Non-Communicable Diseases — MCQs

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