Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 531: Chikungunya is transmitted by

A. Aedes (Correct Answer)
B. Anopheles
C. Mansonia
D. Culex

Explanation: ***Aedes*** - **Chikungunya virus** is primarily transmitted to humans through the bites of infected **Aedes aegypti** and **Aedes albopictus** mosquitoes. - These mosquitoes are characterized by their **daytime biting** habits and often breed in **domestic water containers**. *Anopheles* - **Anopheles mosquitoes** are the primary vectors for **malaria**, transmitting **Plasmodium parasites**. - They are generally more active during **dusk and dawn** and are not known to transmit chikungunya. *Mansonia* - **Mansonia mosquitoes** are known vectors for certain types of **filariasis** (e.g., Brugian filariasis) and some arboviruses, but not chikungunya. - They are distinctive for their larvae attaching to and obtaining oxygen from the **roots of aquatic plants**. *Culex* - **Culex mosquitoes** are significant vectors for a variety of diseases, including **West Nile virus**, **Japanese encephalitis**, and **filariasis**. - While they can transmit a range of arboviruses, they are not the primary vectors for chikungunya.

Question 532: Louse transmits:

A. Chagas disease
B. Sleeping sickness
C. Trench fever (Correct Answer)
D. Chikungunya fever

Explanation: ***Trench fever*** - **Trench fever** is caused by the bacterium *Bartonella quintana*, which is primarily transmitted to humans through the feces of the **body louse** (*Pediculus humanus corporis*). - The louse vector plays a crucial role in spreading the infection, especially in crowded and unsanitary conditions. *Chagas disease* - **Chagas disease** is caused by the parasite *Trypanosoma cruzi* and is transmitted by blood-sucking **reduviid bugs** (also known as "kissing bugs"), not lice. - The parasite is typically transmitted when infected bug feces enter the bite wound or mucous membranes. *Sleeping sickness* - **Sleeping sickness** (African trypanosomiasis) is caused by *Trypanosoma brucei* and is transmitted by the bite of infected **tsetse flies**, not lice. - The tsetse fly injects the parasite into the human host during a blood meal. *Chikungunya fever* - **Chikungunya fever** is a viral disease transmitted to humans by infected **mosquitoes**, primarily *Aedes aegypti* and *Aedes albopictus*, not lice. - The virus is spread when these mosquitoes feed on an infected person and then bite another person.

Question 533: Which of the following is not a sexually transmitted disease -

A. Hepatitis B
B. Yaws
C. Amoebiasis (Correct Answer)
D. Bacterial vaginosis

Explanation: ***Amoebiasis*** - Amoebiasis is caused by the parasite **Entamoeba histolytica** and is primarily transmitted through the **oral-fecal route**, often via contaminated food or water. - It is **not considered a sexually transmitted infection** in standard medical classifications, though rare transmission through oral-anal sexual contact has been documented. - This is the expected answer for diseases NOT primarily transmitted sexually. *Hepatitis B* - **Hepatitis B virus (HBV)** is readily transmitted through sexual contact, especially through the exchange of bodily fluids (blood, semen, vaginal fluids). - It is a **well-recognized sexually transmitted infection**, along with transmission through blood products and vertical transmission from mother to child. *Yaws* - Yaws is caused by the bacterium **Treponema pallidum pertenue** and is transmitted through **direct non-sexual skin-to-skin contact** with infectious lesions. - It is a **tropical disease primarily affecting children** through casual contact during play and is **NOT classified as a sexually transmitted disease**. - Note: While technically not an STD, amoebiasis is the conventional answer as yaws may appear in some older classifications of contact-transmitted diseases. *Bacterial vaginosis* - Bacterial vaginosis (BV) is an imbalance of naturally occurring vaginal bacteria, which can be influenced by sexual activity. - While **not strictly an STI** in the traditional sense (not caused by a single transmissible pathogen), it is more common in sexually active women and is often evaluated in STI clinics.

Question 534: Surgical gloves are disposed in which BMW category ?

A. Solid Waste
B. Yellow Category (Infectious Waste) (Correct Answer)
C. Expired or Discarded Medicines
D. Human Anatomical Waste

Explanation: ***Yellow Category (Infectious Waste)*** - Surgical gloves are classified as **infectious waste** because they come into contact with blood, body fluids, and other potentially infectious materials during surgical procedures. - The Yellow Category in Bio-Medical Waste Management (BMW) Rules is designated for infectious waste, including items contaminated with **blood and body fluids**. - This is the correct disposal category for used surgical gloves. *Solid Waste* - This is a broad category for general waste that is not infectious or hazardous. - Surgical gloves, due to their potential contamination with infectious materials, are classified more specifically as biomedical waste under the Yellow category, not general solid waste. *Expired or Discarded Medicines* - This category is for pharmaceutical waste, including unused or expired medications. - Surgical gloves are medical devices used for protection, not medicinal products, and therefore do not belong in this category. *Human Anatomical Waste* - This category includes human tissues, organs, body parts, and recognizable anatomical specimens. - Surgical gloves are protective barriers used during procedures, not anatomical waste from the patient, and are classified separately as infectious waste.

Question 535: All are true regarding Japanese encephalitis disease except:

A. Man acts as reservoir (Correct Answer)
B. Pig vaccination control transmission
C. Vector is Culex vishnui
D. None of the options are true

Explanation: ***Man acts as reservoir*** - Humans are considered **dead-end hosts** for Japanese encephalitis; they do not develop sufficiently high viremia to transmit the virus back to mosquitoes. - The primary reservoirs for the Japanese encephalitis virus are **pigs** and **wading birds**. *Pig vaccination control transmission* - **Vaccinating pigs** is an effective strategy to control Japanese encephalitis transmission because pigs are significant amplifier hosts, producing high levels of viremia. - By reducing the viral load in the pig population, pig vaccination helps **break the transmission cycle** between mosquitoes and humans. *Vector is Culex vishnui* - The primary vector involved in the transmission of Japanese encephalitis is indeed **Culex mosquitoes**, with **Culex vishnui complex** being a significant group responsible for its spread in many endemic regions. - These mosquitoes primarily breed in **rice paddies** and other stagnant water sources, which are common in areas where the disease is prevalent. *None of the options are true* - This option is incorrect because the statements regarding **pig vaccination** and the **Culex vishnui** vector are true in the context of Japanese encephalitis. - The initial premise that "Man acts as reservoir" is the false statement, making it the correct answer to the "except" question.

Question 536: Contact isolation is done for:

A. Mumps
B. MRSA (Correct Answer)
C. Diphtheria
D. Typhoid

Explanation: ***MRSA*** - **Methicillin-resistant *Staphylococcus aureus* (MRSA)** is transmitted primarily through direct contact with infected patients or contaminated environmental surfaces, necessitating **contact isolation** measures. - These measures include the use of **gloves and gowns** upon entering the patient's room to prevent spread. *Mumps* - Mumps is a viral infection primarily transmitted via **respiratory droplets**, requiring **droplet isolation** rather than contact isolation. - The virus spreads through coughing and sneezing, necessitating measures like wearing a surgical mask. *Diphtheria* - Diphtheria, caused by *Corynebacterium diphtheriae*, is spread through **respiratory droplets** from close contact with an infected person, requiring **droplet isolation**. - This typically involves wearing a mask and sometimes eye protection. *Typhoid* - Typhoid fever is a **fecal-oral disease** caused by *Salmonella Typhi*, transmitted through contaminated food and water. - While proper hand hygiene is crucial, it generally does not require specific isolation precautions beyond **standard precautions** in a hospital setting for most patients.

Question 537: The online software used to monitor TB control program under RNTCP is:

A. NIRBHAI
B. NIKSHAY (Correct Answer)
C. e-DOTS
D. NISCHAY

Explanation: ***Correct Answer: NIKSHAY*** - **NIKSHAY** is the official **web-based patient management system** for monitoring the TB control program under the **Revised National Tuberculosis Control Programme (RNTCP)**, now known as the National Tuberculosis Elimination Programme (NTEP) - It serves as a comprehensive platform for **real-time case notification, treatment monitoring, and tracking of patient outcomes** - Enables **digital recording** of TB patient details, treatment regimens, and follow-up information across India *Incorrect: NIRBHAI* - This is not a recognized software platform associated with RNTCP or TB control monitoring - No official government health program uses this name for TB surveillance *Incorrect: e-DOTS* - While **DOTS (Directly Observed Treatment, Short-course)** is the core treatment strategy for TB, e-DOTS is not the comprehensive online monitoring software - e-DOTS may refer to electronic recording of DOTS adherence, but **NIKSHAY** is the overarching national platform *Incorrect: NISCHAY* - This is not a recognized software platform for RNTCP monitoring - Does not correspond to any official TB control initiative in India

Question 538: Which of the following is a Category A bioterrorism agent?

A. Brucella
B. Nipah virus
C. Bacillus anthracis (Correct Answer)
D. Coxiella

Explanation: ***Bacillus anthracis*** - **_Bacillus anthracis_** (causing anthrax) is a classic example of a **Category A bioterrorism agent** due to its high mortality, ease of dissemination, and potential for major public health impact. - Category A agents are considered the **highest priority** because they pose a significant risk to national security. *Brucella* - **_Brucella_** species are classified as **Category B bioterrorism agents**. - They are moderately easy to disseminate and can cause moderate morbidity but generally have a **low mortality rate**. *Nipah virus* - **Nipah virus** is categorized as a **Category C bioterrorism agent**. - These are emerging pathogens that could be engineered for mass dissemination in the future, but their current risk is lower than Category A or B. *Coxiella* - **_Coxiella burnetii_** (causing Q fever) is classified as a **Category B bioterrorism agent**. - It is relatively easy to disseminate and can cause high morbidity but has a **low mortality rate**.

Question 539: Nosocomial infections are diagnosed after how many hours of hospitalization / admission?

A. 48 hours (Correct Answer)
B. 96 hours
C. 72 hours
D. 24 hours

Explanation: ***48 hours*** - Nosocomial infections, also known as **hospital-acquired infections (HAIs)**, are defined as infections that develop at least **48 hours** after hospital admission. - This time frame helps differentiate infections acquired in the hospital setting from those the patient was incubating upon admission. *96 hours* - A 96-hour threshold is **too long** for the standard definition of a nosocomial infection. - Infections emerging after this extended period would almost certainly be considered hospital-acquired, but the conventional diagnostic window is shorter. *72 hours* - While 72 hours might capture many HAIs, it is **not the universally accepted or most common cutoff** for defining a nosocomial infection. - The 48-hour mark is more widely used for epidemiological and diagnostic purposes. *24 hours* - Infections diagnosed within **24 hours** of admission are typically considered to have been present or incubating **prior to hospitalization**. - This short timeframe is generally insufficient to classify an infection as hospital-acquired.

Question 540: Vector for Zika virus disease is:

A. Culex
B. Aedes Aegypti (Correct Answer)
C. Phlebotomus
D. Anopheles stephensi

Explanation: ***Aedes aegypti*** - The **Aedes aegypti mosquito** is the primary vector responsible for transmitting the Zika virus to humans. - This mosquito species is also known to transmit other arboviruses, including **dengue** and **chikungunya** viruses. *Culex* - **Culex mosquitoes** are known vectors for diseases such as **West Nile virus** and **Japanese encephalitis**. - They are generally not considered primary vectors for the Zika virus. *Phlebotomus* - **Phlebotomus (sandflies)** are vectors for parasitic diseases, most notably **leishmaniasis**. - They are not involved in the transmission of viral infections like Zika. *Anopheles stephensi* - **Anopheles mosquitoes**, particularly *Anopheles stephensi*, are the main vectors for **malaria**. - They do not play a role in the transmission of the Zika virus.

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