Non-Communicable Diseases Practice Questions

Q: Rabies can be transmitted by all of the following routes except?

Ingestion. ### Explanation **Correct Option: C (Ingestion)** **Reasoning:** Rabies is caused by the **Lyssavirus Type 1** (a neurotropic RNA virus). The virus is highly fragile and is inactivated by gastric acid (low pH) and digestive enzymes. Therefore, the ingestion of milk or meat from a rabid animal does not transmit the disease, as the virus cannot survive the gastrointestinal environment to reach the nervous system. **Analysis of Other Options:** * **Bites (Option B):** This is the most common route (over 99% of human cases). The virus is present in the saliva of the rabid animal and is inoculated into the host via a bite. * **Licks (Option D):** Transmission occurs if the saliva of a rabid animal comes into contact with **pre-existing scratches, open wounds, or intact mucous membranes** (eyes, mouth). This is classified as a Category II or III exposure depending on the severity. * **Aerosol (Option A):** Though rare, transmission can occur via inhalation of virus-laden aerosols. This has been documented in specific laboratory accidents and among individuals exploring caves heavily populated by infected bats (guano-rich environments). **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** Typically 1–3 months (Range: 1 year). It depends on the distance of the bite from the CNS and the viral load. * **Organ Transplant:** Rabies can be transmitted via **corneal or solid organ transplants** from infected donors. * **Diagnosis:** The presence of **Negri bodies** (intracytoplasmic inclusions) in the hippocampus or cerebellum is pathognomonic (post-mortem). * **Category III Exposure:** Includes single/multiple transdermal bites, licks on broken skin, or contamination of mucous membranes with saliva. This requires both **Vaccine and Rabies Immunoglobulin (RIG)**.

Q: Which of the following diseases is associated with a chronic carrier state?

Typhoid. **Explanation:** The concept of a **carrier state** refers to an individual who harbors a specific infectious agent without showing clinical signs of the disease but serves as a potential source of infection to others. **Why Typhoid is Correct:** *Salmonella typhi* is notorious for establishing a **chronic carrier state** (defined as excreting the bacilli for more than one year). The bacteria typically persist in the **gallbladder** (biliary carriers) or, less commonly, in the urinary tract. This state is more frequent in females and those with pre-existing gallstones. The classic historical example is "Typhoid Mary." **Why Other Options are Incorrect:** * **Measles:** This is an acute viral infection characterized by high infectivity during the prodromal stage. It does **not** have a carrier state; an individual is either infected and symptomatic or immune. * **Whooping Cough (Pertussis):** There is no known chronic carrier state for *Bordetella pertussis*. Transmission occurs via respiratory droplets from active cases. * **Influenza:** This is an acute respiratory viral infection. While subclinical infections occur, there is no chronic carrier state; the virus is cleared rapidly by the immune system or leads to acute illness. **High-Yield NEET-PG Pearls:** 1. **Incubatory Carrier:** Sheds infectious agent during the incubation period (e.g., Measles, Mumps, Polio). 2. **Convalescent Carrier:** Sheds agent during recovery (e.g., Typhoid, Dysentery). 3. **Chronic Carrier:** Sheds agent for indefinite periods (e.g., Typhoid, Hepatitis B, HIV). 4. **Typhoid Management:** The drug of choice for clearing the typhoid carrier state is **Ampicillin** (often combined with Probenecid) or **Ciprofloxacin** for 4–6 weeks. Cholecystectomy may be required if gallstones are present.

Q: The Cheopis Index is used for which disease?

Plague. **Explanation:** The **Cheopis Index** is a specific entomological parameter used in the surveillance and control of **Plague**. It refers to the average number of *Xenopsylla cheopis* (the Oriental rat flea) found per rat. Since *X. cheopis* is the most efficient vector for transmitting *Yersinia pestis* from rats to humans, a high index indicates an increased risk of a plague outbreak. An index greater than **1.0** is considered the critical threshold for potential epidemic spread. **Analysis of Options:** * **Plague (Correct):** In addition to the Cheopis Index, other indices used include the *Specific Flea Index* and the *Percentage Flea Index*. Monitoring these helps in timing insecticide sprays to prevent human transmission. * **Rabies:** Surveillance focuses on animal bite statistics and post-exposure prophylaxis (PEP) coverage, not flea indices. It is a viral zoonosis transmitted via saliva. * **Yellow Fever:** The relevant indices here are the **Aedes indices** (e.g., House Index, Container Index, and Breteau Index), as the disease is transmitted by *Aedes aegypti* mosquitoes. * **Leishmaniasis (Kala-azar):** This is transmitted by the **Sandfly** (*Phlebotomus argentipes*). Surveillance involves monitoring the sandfly density in human dwellings. **High-Yield Clinical Pearls for NEET-PG:** * **Vector of Plague:** *Xenopsylla cheopis* (most common/efficient) and *Xenopsylla astia*. * **Critical Cheopis Index:** >1 (indicates immediate danger of an outbreak). * **Drug of Choice (Treatment):** Streptomycin (Gentamicin is an alternative). * **Drug of Choice (Chemoprophylaxis):** Doxycycline or Tetracycline. * **Quarantine Period:** 6 days for international travelers coming from endemic zones.

Q: Which vaccine is contraindicated in pregnancy?

Varicella. **Explanation:** The core principle in obstetric immunization is that **live attenuated vaccines** are generally **contraindicated** during pregnancy. This is due to the theoretical risk of the vaccine virus crossing the placenta and causing fetal infection or congenital anomalies. **1. Why Varicella is the Correct Answer:** The Varicella vaccine contains a live attenuated virus (Oka strain). Administration during pregnancy poses a risk of **Congenital Varicella Syndrome**, characterized by limb hypoplasia, skin scarring, and microcephaly. Women are advised to avoid pregnancy for at least 28 days (1 month) after receiving this vaccine. **2. Analysis of Incorrect Options:** * **Hepatitis A & B:** These are **inactivated (killed) or recombinant vaccines**. They are not contraindicated if the risk of infection is high. Hepatitis B vaccination is specifically indicated for pregnant women at risk of occupational exposure or those with infected partners. * **Rabies:** This is a **post-exposure prophylaxis (PEP)** vaccine. Since rabies is 100% fatal, the vaccine is **never contraindicated** in pregnancy if a category II or III bite occurs. Life-saving interventions always take precedence. **3. NEET-PG High-Yield Pearls:** * **Absolute Contraindications in Pregnancy:** Live vaccines like **MMR (Measles, Mumps, Rubella)**, **Varicella**, **Yellow Fever**, and **BCG**. * **The Exception:** Yellow Fever vaccine may be given if travel to an endemic area is unavoidable and the risk of disease outweighs the risk of vaccination. * **Safest/Recommended:** **Tetanus, Diphtheria, and acellular Pertussis (Tdap)** is recommended in every pregnancy (ideally between 27–36 weeks) to provide passive immunity to the neonate. * **Influenza:** The **inactivated** injectable flu vaccine is safe and recommended in any trimester; however, the **Live Attenuated Influenza Vaccine (LAIV/Nasal spray)** is contraindicated.

Q: Four split skin smears from a single patient show the following results: Two samples contain 10 bacilli per 100 high power fields (hpf), and two samples contain over 1000 bacilli per average fields. What is the bacteriological index?

3.5. To solve this question, we must first determine the **Bacteriological Index (BI)** for each individual smear using Ridley’s Logarithmic Scale and then calculate the average. ### 1. Understanding the Calculation The BI is calculated based on the density of *M. leprae* in skin smears: * **1+**: 1–10 bacilli per 100 high power fields (hpf) * **2+**: 1–10 bacilli per 10 hpf * **3+**: 1–10 bacilli per average field * **4+**: 10–100 bacilli per average field * **5+**: 100–1000 bacilli per average field * **6+**: >1000 bacilli per average field **Step-by-step calculation for this patient:** * **Smears 1 & 2:** 10 bacilli/100 hpf = **1+** (each) * **Smears 3 & 4:** >1000 bacilli/avg field = **6+** (each) * **Total BI Sum:** 1 + 1 + 6 + 6 = **14** * **Average BI:** 14 ÷ 4 (total sites) = **3.5** ### 2. Why Other Options are Incorrect * **B (4.5), C (5.5), D (6.5):** These values result from incorrect application of the Ridley scale or mathematical errors in averaging. For instance, a BI of 6.5 is impossible as the maximum scale value is 6. ### 3. High-Yield Clinical Pearls for NEET-PG * **Sites for Smear:** Usually taken from 4–6 sites (e.g., both earlobes, two lesions, and the nasal mucosa). * **BI vs. MI:** While **BI** measures the total bacterial load (living and dead), the **Morphological Index (MI)** measures the percentage of solid-staining (viable) bacilli. * **WHO Classification:** * **Paucibacillary (PB):** BI < 2 at all sites. * **Multibacillary (MB):** BI ≥ 2 at any site (though clinically, any positive smear is now treated as MB). * **Treatment Duration:** MB Leprosy requires 12 months of MDT (Rifampicin, Dapsone, Clofazimine), while PB requires 6 months (Rifampicin, Dapsone).

Q: What is true about the epidemiology of influenza?

Extra-human reservoirs are seen.. ### Explanation **Correct Answer: D. Extra-human reservoirs are seen.** Influenza viruses, particularly **Influenza A**, exhibit a vast extra-human reservoir. They infect a wide range of animals and birds (e.g., ducks, chickens, pigs, horses, and seals). These reservoirs are crucial for the emergence of new subtypes through **antigenic shift** (genetic reassortment), which can lead to pandemics. In contrast, Influenza B and C are almost exclusively human pathogens. **Analysis of Incorrect Options:** * **A. Asymptomatic cases are seen rarely:** This is incorrect. Subclinical or asymptomatic infections are quite common in influenza and play a significant role in the rapid spread of the virus within a community. * **B. The incubation period is 10-12 hours:** This is incorrect. The incubation period for influenza is typically **1 to 4 days**, with an average of **2 days**. It is short, but not as brief as 10 hours. * **C. Pandemics are rare:** While pandemics do not occur every year, they are a characteristic feature of Influenza A. Major pandemics have occurred at intervals (e.g., 1918, 1957, 1968, and 2009). The statement is misleading because the *potential* for pandemics is a defining epidemiological trait of the virus. **High-Yield NEET-PG Pearls:** * **Antigenic Shift:** Major abrupt change (reassortment) in Influenza A only; leads to **Pandemics**. * **Antigenic Drift:** Minor point mutations in Influenza A and B; leads to **Epidemics** and necessitates annual vaccine updates. * **Period of Communicability:** Adults are infectious from 1 day before to 5 days after the onset of symptoms. * **Drug of Choice:** Oseltamivir (Neuraminidase inhibitor) is the preferred treatment for both seasonal and avian flu. * **Vaccine:** The most common is the **Inactivated (killed)** vaccine given IM; the Live Attenuated Influenza Vaccine (LAIV) is administered intranasally.

Q: After vaccination against Japanese encephalitis, when does immunity develop?

30 days. **Explanation:** The correct answer is **30 days (Option A)**. In the context of Japanese Encephalitis (JE) vaccination, particularly with the live attenuated SA 14-14-2 vaccine (which is the strain used in India's Universal Immunization Programme), it takes approximately one month for the body to mount a protective immune response. **Why 30 days is correct:** Immunity following JE vaccination is not immediate. Studies on seroconversion indicate that while some antibodies appear earlier, a robust, protective level of neutralizing antibodies (titer ≥1:10) typically develops by **4 weeks (28-30 days)** post-vaccination. This timeframe is crucial for public health planning during outbreaks or before traveling to endemic areas. **Analysis of Incorrect Options:** * **7 days (Option B):** This is too early for a primary immune response to reach protective thresholds. * **10 days (Option C):** While some IgM may be detectable, the protective IgG response is still maturing. * **21 days (Option D):** Although the immune response is well underway, the standard clinical and textbook consensus for full immunity is 30 days. **High-Yield Facts for NEET-PG:** * **Vaccine Strain:** The most common vaccine used in India is the **SA 14-14-2** (Live Attenuated, Chinese origin). * **UIP Schedule:** Two doses are given under the Universal Immunization Programme—the 1st dose at **9 months** (with Measles/MR) and the 2nd dose at **16–24 months** (with DPT booster). * **Route:** Subcutaneous (0.5 ml). * **Vector:** Primarily transmitted by the **Culex tritaeniorhynchus** mosquito, which breeds in stagnant water like rice fields. * **Amplifier Host:** The **Pig** is the most important amplifier host (the mosquito-pig-mosquito cycle). Humans are "dead-end" hosts.

Question 1

Rabies can be transmitted by all of the following routes except?

Accepted Answer

Ingestion

Answer

Aerosol

Answer

Bites

Answer

Licks

Question 2

Which of the following diseases is associated with a chronic carrier state?

Accepted Answer

Typhoid

Answer

Measles

Answer

Whooping cough

Answer

Influenza

Question 3

Which of the following is an AIDS-defining criterion as per WHO?

Accepted Answer

Generalized lymphadenopathy

Answer

Fever, weight loss, and fatigue

Answer

Pneumocystis carinii Pneumonia

Answer

Mycobacterium avium infection

Question 4

The Cheopis Index is used for which disease?

Accepted Answer

Plague

Answer

Rabies

Answer

Yellow fever

Answer

Leishmaniasis

Question 5

Which vaccine is contraindicated in pregnancy?

Accepted Answer

Varicella

Answer

Hepatitis A

Answer

Rabies

Answer

Hepatitis B

Question 6

Which of the following statements about whooping cough is false?

Accepted Answer

Asymptomatic carriers are the most important source of infection.

Answer

It commonly affects children under 1 year of age.

Answer

Primary cases are the most important source of infection.

Answer

The secondary attack rate is high.

Question 7

Four split skin smears from a single patient show the following results: Two samples contain 10 bacilli per 100 high power fields (hpf), and two samples contain over 1000 bacilli per average fields. What is the bacteriological index?

Accepted Answer

3.5

Answer

4.5

Answer

5.5

Answer

6.5

Question 8

What is true about the epidemiology of influenza?

Accepted Answer

Extra-human reservoirs are seen.

Answer

Asymptomatic cases are seen rarely.

Answer

The incubation period is 10-12 hours.

Answer

Pandemics are rare.

Question 9

All of the following are zoonotic infections EXCEPT?

Accepted Answer

HIV

Answer

Plague

Answer

Japanese Encephalitis

Answer

Tuberculosis

Question 10

After vaccination against Japanese encephalitis, when does immunity develop?

Accepted Answer

30 days

Answer

7 days

Answer

10 days

Answer

21 days

Non-Communicable Diseases — MCQs

Non-Communicable Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?