Community Medicine
6 questionsVaccine derived polio virus outbreaks are due to?
Which of the following statements regarding polio vaccination is false?
Reservoir of infection in enteric fever?
Among the following options, the minimum acceptable Rideal-Walker coefficient for disinfectant used for cholera stool would be?
Most common route of nosocomial infection [Hospital-acquired infection]?
Behavioral surveillance survey is done in?
NEET-PG 2015 - Community Medicine NEET-PG Practice Questions and MCQs
Question 931: Vaccine derived polio virus outbreaks are due to?
- A. Type-2 poliovirus (Correct Answer)
- B. Type-3 poliovirus
- C. Type-1 poliovirus
- D. All types of poliovirus
Explanation: ***Type-2 poliovirus*** - The **type 2 poliovirus (PV2)** component of the oral polio vaccine (OPV) has historically been associated with the majority of vaccine-derived poliovirus (VDPV) outbreaks. - The **attenuated PV2 strain** in OPV can revert to neurovirulent forms in rare cases, leading to outbreaks, especially in areas with low vaccination coverage. - Type 2 was responsible for **>90% of circulating VDPV (cVDPV) cases**, which led to the global switch from trivalent OPV to bivalent OPV (without type 2) in April 2016. *Type-3 poliovirus* - While **type 3 poliovirus (PV3)** was also part of OPV, **wild type 3 poliovirus was declared eradicated in 2019** (last case in 2012). - VDPV outbreaks due to PV3 are rare compared to PV2. *Type-1 poliovirus* - **Type 1 poliovirus (PV1)** is still endemic in some regions and causes wild poliovirus (WPV) infections. - Although PV1 is included in bivalent OPV, **VDPV outbreaks** from the PV1 component are very rare compared to PV2. *All types of poliovirus* - While all three serotypes of poliovirus were historically included in trivalent OPV, **PV2 is overwhelmingly responsible** for VDPV outbreaks. - **Wild type 2 poliovirus was eradicated in 2015** (last case 1999), but the vaccine strain continued to cause VDPV outbreaks until type 2 was removed from routine OPV.
Question 932: Which of the following statements regarding polio vaccination is false?
- A. OPV induces both humoral and intestinal immunity
- B. IPV is given intramuscularly
- C. First OPV is given at 4 weeks (Correct Answer)
- D. Both killed and live vaccines are available
Explanation: ***First OPV is given at 4 weeks*** - The first dose of **Oral Polio Vaccine (OPV)** is typically given at birth, often referred to as the **"zero dose,"** before the 4-week mark. - Subsequent doses are given at 6, 10, and 14 weeks of age as part of the routine immunization schedule, making the statement that the first OPV is given at 4 weeks false. *OPV induces both humoral and intestinal immunity* - **OPV** is a **live attenuated vaccine** that replicates in the gut, thereby stimulating both a systemic **humoral immune response** (producing antibodies in the bloodstream) and **local intestinal immunity** (IgA antibodies in the gut). - This **intestinal immunity** is crucial for preventing viral replication in the gut and reducing transmission. *IPV is given intramuscularly* - The **Inactivated Polio Vaccine (IPV)**, also known as the **Salk vaccine**, is administered via injection, specifically through the **intramuscular route**. - This method ensures systemic absorption and the development of **humoral immunity**. *Both killed and live vaccines are available* - There are two main types of polio vaccines: **Oral Polio Vaccine (OPV)**, which is a **live attenuated vaccine**, and **Inactivated Polio Vaccine (IPV)**, which is a **killed vaccine**. - Both types have been instrumental in polio eradication efforts, each with distinct advantages and disadvantages.
Question 933: Reservoir of infection in enteric fever?
- A. Birds
- B. Cow
- C. Man (Correct Answer)
- D. Water
Explanation: ***Man*** - Humans are the **sole natural reservoir** for *Salmonella Typhi* and *Salmonella Paratyphi*, the causative agents of enteric fever (typhoid and paratyphoid fever). - The bacteria can persist in the **gallbladder** of asymptomatic carriers, who can then shed the bacteria in their feces, contributing to transmission. *Birds* - Birds are not considered a primary reservoir for the **causative pathogens of enteric fever** (*Salmonella Typhi* or *Paratyphi*). - They are more commonly associated with other *Salmonella* serotypes, such as *Salmonella Enteritidis*, which cause **gastroenteritis** rather than systemic enteric fever. *Cow* - Cows are not a primary reservoir for the organisms responsible for **enteric fever**; these pathogens are specifically adapted to humans. - While cows can carry various *Salmonella* species, they are typically associated with **foodborne outbreaks** of *Salmonella*-induced **gastroenteritis**, not typhoid fever. *Water* - Water is a **vehicle for transmission** of enteric fever, becoming contaminated with human feces containing *Salmonella Typhi* or *Paratyphi*. - It is not a reservoir because the bacteria do not naturally **multiply or persist indefinitely** in water without a human source.
Question 934: Among the following options, the minimum acceptable Rideal-Walker coefficient for disinfectant used for cholera stool would be?
- A. 4
- B. 10
- C. 2 (Correct Answer)
- D. 7
Explanation: ***2 (Minimum acceptable among given options)*** - The **Rideal-Walker coefficient** measures disinfectant efficacy relative to phenol as the standard reference - A coefficient of **2** means the disinfectant is **twice as effective** as phenol against test organisms (*Salmonella typhi* and *Staphylococcus aureus*) - While higher coefficients are preferred for highly infectious materials like cholera stool, **2 represents the minimum acceptable threshold** among the given options that still provides reasonable disinfection efficacy - Standard practice recommends disinfectants with RW coefficient ≥5 for cholera stool, but among the choices provided, 2 is the lowest that meets basic acceptability criteria *4 (Better choice but not the minimum)* - A coefficient of **4** means the disinfectant is **four times more effective** than phenol - This provides **more robust disinfection** and would be preferred over a coefficient of 2 - However, the question specifically asks for the **minimum acceptable** value, not the optimal value - Among the options, this is not the minimum *7 (Highly effective)* - A coefficient of **7** indicates the disinfectant is **seven times more potent** than phenol - This represents **very good disinfection efficacy** and exceeds minimum requirements - This is well above the minimum acceptable threshold *10 (Excellent efficacy)* - A coefficient of **10** means the disinfectant is **ten times more effective** than phenol - This represents **excellent disinfection power** with a very high safety margin - While ideal for high-risk situations, this far exceeds the minimum acceptable requirement
Question 935: Most common route of nosocomial infection [Hospital-acquired infection]?
- A. Droplet transmission
- B. Direct contact (Correct Answer)
- C. Indirect contact
- D. Vehicle transmission
Explanation: **Direct contact** - **Direct contact** with colonized or infected patients is the predominant mode of transmission for many common nosocomial pathogens like **MRSA** and **VRE**. - This often involves healthcare workers' hands becoming contaminated and then touching other patients. *Droplet transmission* - Involves the transmission of infectious agents through **respiratory droplets** produced during coughing, sneezing, or talking. - While significant for some infections (e.g., influenza, pertussis), it is not the most common route overall for nosocomial infections. *Indirect contact* - Occurs when an infectious agent is transferred via a **contaminated intermediate object** or person. - Although important (e.g., contaminated medical devices), it is generally less frequent than direct patient-to-patient transmission. *Vehicle transmission* - Involves transmission through **contaminated inanimate vehicles** like food, water, medications, or surgical instruments. - While outbreaks can occur via this route (e.g., contaminated endoscopes), it is not the most common day-to-day transmission mechanism in hospitals.
Question 936: Behavioral surveillance survey is done in?
- A. AIDS (Correct Answer)
- B. TB
- C. Filaria
- D. Malaria
Explanation: ***AIDS*** - Behavioral surveillance surveys are crucial for understanding and monitoring behaviors related to **HIV transmission**, such as sexual practices and drug use, among at-risk populations. - These surveys help in designing and evaluating **prevention programs** by identifying trends in risky behaviors and knowledge, attitudes, and practices (KAP) concerning HIV. *Filaria* - Surveillance for filaria primarily involves **entomological surveys** (mosquito monitoring) and **parasitological surveys** (blood examinations for microfilariae). - Behavioral aspects are less central to direct surveillance compared to disease vectors and infection rates. *TB* - Tuberculosis surveillance mainly focuses on **case detection**, **treatment outcomes**, and monitoring **drug resistance** through clinical and laboratory data. - While patient adherence to treatment involves behavior, there isn't a dedicated "behavioral surveillance survey" method specifically for TB. *Malaria* - Malaria surveillance involves monitoring **parasitemia rates**, **vector populations**, and **antimalarial drug resistance**. - Behavioral components like bed net usage are important, but the primary surveillance methods are not termed "behavioral surveillance surveys" in the same structured way as for HIV.
Microbiology
3 questionsWhat is a common characteristic of the H5N1 and H7N7 strains of influenza?
Capsular polysaccharide derived vaccine is available for all meningococci except?
A woman traveling from Bihar to Delhi is suspected to have Kala-azar. Suitable investigation is?
NEET-PG 2015 - Microbiology NEET-PG Practice Questions and MCQs
Question 931: What is a common characteristic of the H5N1 and H7N7 strains of influenza?
- A. Frequent endemic infection in man
- B. Have same frequency of antigenic variation
- C. Strains of avian influenza (Correct Answer)
- D. None of the options
Explanation: ***Strains of avian influenza*** - Both **H5N1** and **H7N7** are well-known subtypes of the **influenza A virus** that primarily infect birds. - While they can infect humans, their natural reservoir and main hosts are **avian species**. *Frequent endemic infection in man* - These strains are not endemic in humans; human infections are typically **sporadic** and associated with close contact with infected birds. - They lack efficient **human-to-human transmission**, which prevents them from becoming endemic in the human population. *Have same frequency of antigenic variation* - Although both undergo **antigenic variation**, the specific frequency and patterns can differ between strains and are influenced by various factors, including their host range and circulation dynamics. - It is inaccurate to assume identical frequencies of **antigenic drift** and **shift** for different viral subtypes. *None of the options* - This option is incorrect because "Strains of avian influenza" is a correct and common characteristic shared by both H5N1 and H7N7.
Question 932: Capsular polysaccharide derived vaccine is available for all meningococci except?
- A. Group C
- B. Group B (Correct Answer)
- C. Group Y
- D. Group A
Explanation: ***Group B*** - The capsular polysaccharide of **Group B meningococci** is composed of **polysialic acid**, which is poorly immunogenic in humans because it structurally mimics human neural cell adhesion molecules. - Due to its **poor immunogenicity** and risk of autoantibody production, traditional polysaccharide vaccines are ineffective against Group B. *Group A* - Polysaccharide vaccines for **Group A meningococci** (e.g., in Menactra, Menveo) are effective in inducing a protective immune response. - Group A is a major cause of meningococcal disease, particularly in the **"meningitis belt"** of sub-Saharan Africa. *Group C* - **Capsular polysaccharide vaccines** are available and effective against Group C meningococcal disease, often included in quadrivalent formulations. - These vaccines elicit a robust **antibody response** against the Group C polysaccharide. *Group Y* - Vaccines containing the **capsular polysaccharide** of Group Y meningococci are effective and commonly included in quadrivalent vaccines. - Group Y is a significant cause of meningococcal disease, particularly in **North America and Europe**.
Question 933: A woman traveling from Bihar to Delhi is suspected to have Kala-azar. Suitable investigation is?
- A. P24 antigen
- B. Rk-39 test (Correct Answer)
- C. Combo RDT
- D. HRP-2 antigen
Explanation: ***Rk-39 test*** - The **Rk-39 test** is a rapid diagnostic test highly sensitive and specific for detecting antibodies against the **kinesin-related protein K39** of *Leishmania donovani*, the causative agent of **Kala-azar (visceral leishmaniasis)**. - It is particularly useful in **endemic regions** like Bihar for quick and accurate diagnosis, especially in patients with suspected Kala-azar presenting with fever, splenomegaly, and pancytopenia. *P24 antigen* - **P24 antigen** testing is primarily used for the diagnosis of **HIV infection**. - It detects the **core protein p24** of the HIV virus, which is not relevant for the diagnosis of Kala-azar. *Combo RDT* - A **Combo RDT** (Rapid Diagnostic Test), without further specification, typically refers to tests for **malaria**, which detect antigens like **HRP-2** and **aldolase**. - While RDTs are used for parasitic diseases, this general term does not specifically refer to a test for **Kala-azar**. *HRP-2 antigen* - **HRP-2 (Histidine-rich protein 2) antigen** is a specific marker for **Plasmodium falciparum**, used in the diagnosis of **malaria**. - It is not associated with the diagnosis of **Kala-azar**, which is caused by *Leishmania donovani*.
Pharmacology
1 questionsWhich of the following medications is not indicated for the treatment or prophylaxis of seasonal influenza?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 931: Which of the following medications is not indicated for the treatment or prophylaxis of seasonal influenza?
- A. Amantadine
- B. Rimantadine
- C. Oseltamivir
- D. Acyclovir (Correct Answer)
Explanation: ***Acyclovir*** - **Acyclovir** is an antiviral medication specifically used to treat infections caused by **herpes viruses** (e.g., HSV, VZV), not influenza viruses. - It works by inhibiting **viral DNA polymerase**, a mechanism distinct from how anti-influenza drugs act. - **This drug has never been indicated for influenza** - it is the correct answer to this "not indicated" question. *Amantadine* - **Amantadine** is an M2 ion channel inhibitor that **was indicated** for influenza A treatment and prophylaxis. - Although no longer recommended due to widespread **resistance** among circulating influenza strains, it remains a drug that was formally indicated for seasonal influenza. *Rimantadine* - **Rimantadine** is also an M2 ion channel inhibitor, structurally related to amantadine, with a similar mechanism of action. - Like amantadine, it **was indicated** for influenza treatment or prophylaxis but is no longer recommended due to high rates of **resistance** in circulating influenza A viruses. *Oseltamivir* - **Oseltamivir** is a **neuraminidase inhibitor** currently approved and recommended for the treatment and prophylaxis of both influenza A and B. - It reduces viral spread by preventing the release of new virions from infected cells and remains a first-line agent for seasonal influenza.