Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 271: The primary function of NIH (National Institutes of Health) is

A. Medical research (Correct Answer)
B. Public health policy
C. Clinical trials
D. Disease surveillance

Explanation: ***Medical research*** - The **National Institutes of Health (NIH)** is the primary biomedical research agency of the United States, comprising 27 institutes and centers - Its stated mission is to seek fundamental knowledge about living systems and apply that knowledge to **enhance health, lengthen life, and reduce illness and disability** - The NIH conducts and funds **medical research** across virtually all areas of medicine and public health, making this its core primary function - It is the world's largest public funder of biomedical research, with a budget primarily dedicated to research grants and intramural research programs *Disease surveillance* - Disease surveillance is primarily the responsibility of the **CDC (Centers for Disease Control and Prevention)**, not the NIH - While NIH research may inform surveillance strategies, **monitoring and tracking disease patterns** is not the NIH's primary organizational function - The NIH focuses on understanding disease mechanisms and developing interventions through research *Public health policy* - The NIH provides **evidence-based research** that informs public health policy but does not primarily create or enforce policy - Policy-making authority rests with the **Department of Health and Human Services (HHS)** and other regulatory agencies like the FDA - The NIH's role is to generate the scientific knowledge base that guides policy decisions *Clinical trials* - The NIH conducts and funds extensive **clinical trials** through its Clinical Center and grant mechanisms - However, clinical trials are a **methodology of medical research**, not a separate primary function - Clinical trials serve the broader mission of medical research by testing hypotheses and interventions developed through basic and translational research

Question 272: Provision of services at Suraksha Clinic includes

A. Blood transfusion safety services
B. Immunization services
C. STI/RTI services (Correct Answer)
D. Diarrhea control services

Explanation: ***STI/RTI services*** - **Suraksha clinics** are specifically designed under the National AIDS Control Programme (NACP) to provide comprehensive diagnostic, treatment, and counseling services for individuals with **sexually transmitted infections (STIs) and reproductive tract infections (RTIs)** including HIV. - They focus on promoting sexual health and preventing the spread of STIs through education, awareness, and clinical management. *Blood transfusion safety services* - These services are typically handled by **blood banks** and specialized transfusion medicine departments, focusing on donor screening, blood processing, and safe transfusion practices. - They are not a primary service offered by **Suraksha clinics**, which are geared towards STI/RTI management. *Immunization services* - Immunization services are usually provided at **primary health centers**, pediatric clinics, or through public health campaigns aimed at preventing infectious diseases via vaccination. - While important for public health, they are not the core offering of **Suraksha clinics**. *Diarrhea control services* - Diarrhea control services, including oral rehydration therapy and hygiene education, are typically offered by **general practitioners**, community health workers, and maternal and child health programs. - These are distinct from the specialized focus of **Suraksha clinics** on STI/RTI services.

Question 273: Which of the following is not helpful in preventing dracunculiasis?

A. Filtering of drinking water
B. Education regarding water hygiene
C. Active search for new cases
D. Mass mebendazole treatment (Correct Answer)

Explanation: ***Mass mebendazole treatment*** - Dracunculiasis (guinea worm disease) is caused by the nematode *Dracunculus medinensis*, which is transmitted through contaminated water containing copepods (water fleas) infested with larvae. **Mebendazole** is an anthelmintic medication effective against intestinal worms but has no known efficacy against *Dracunculus medinensis*. - This treatment strategy would be **ineffective** in breaking the life cycle of the guinea worm or preventing infection. *Filtering of drinking water* - This is a highly effective method as it removes the **copepods** (water fleas) containing the *Dracunculus medinensis* larvae from drinking water, thus preventing ingestion and infection. - Providing **cloth filters** or teaching filtration techniques is a cornerstone of dracunculiasis eradication programs. *Education regarding water hygiene* - Educating communities about the transmission of the disease through contaminated water and the importance of only drinking safe water is crucial for behavioral change and prevention. - This includes advising against entering water sources when infected to prevent adult worms from releasing larvae, thereby interrupting the **transmission cycle**. *Active search for new cases* - Identifying and isolating individuals with emerging guinea worms allows for proper wound care and prevents them from re-contaminating water sources with new larvae. - This strategy, combined with **containment measures** for infected individuals, is vital for monitoring and interrupting disease transmission in endemic areas.

Question 274: Infections which are transmitted from man to vertebrate animals are called?

A. Amphixenosis
B. Zooanthroponosis (Correct Answer)
C. Anthropozoonosis
D. Enzootics

Explanation: ***Zooanthroponosis*** - This term precisely describes infections transmitted from **humans to vertebrate animals**. - It signifies a specific direction of transmission, distinguishing it from general zoonotic diseases. *Amphixenosis* - This term refers to diseases that can be transmitted **back and forth** between humans and animals, potentially circulating in both populations. - It implies a bidirectional transmission pattern, which is not solely from man to animal. *Anthropozoonosis* - This term describes infections transmitted from **animals to humans**, which is the reverse of what the question asks. - Examples include rabies or leptospirosis, where the animal is the primary source of infection for humans. *Enzootics* - This term describes a disease that is **constantly present** in an animal population within a particular geographic area. - It refers to the endemic occurrence of a disease in animals, not the direction of transmission between species.

Question 275: An 18-year-old college student presents with fever, headache, neck stiffness, and petechial rash on his ankles. Lumbar puncture shows abundance of white blood cells with extracellular as well as intracellular gram-negative diplococci. Select the most appropriate isolation precaution.

A. Airborne precautions
B. Droplet precautions (Correct Answer)
C. Contact precautions
D. Standard precautions

Explanation: ***Droplet precautions*** - The presentation of **fever, headache, neck stiffness, petechial rash**, and **Gram-negative diplococci** in the cerebrospinal fluid confirms **meningococcal meningitis**, which is transmitted via **respiratory droplets**. - **Droplet precautions** are essential to prevent the spread of infectious particles expelled during coughing, sneezing, or talking, which typically travel short distances (within 3 feet) before falling. *Airborne precautions* - **Airborne precautions** are reserved for diseases transmitted by **aerosolized particles** that can remain suspended in the air for longer periods and travel greater distances, such as **tuberculosis** or **measles**. - While **meningitis** can be serious, its primary mode of transmission is through larger droplets, not fine aerosols requiring N95 respirators or negative pressure rooms. *Contact precautions* - **Contact precautions** are indicated for infections spread through **direct contact** with an infected person or **indirect contact** with contaminated surfaces or objects, like **Clostridium difficile** or **MRSA**. - This patient's symptoms and confirmed pathogen indicate a respiratory route of transmission, not primarily through direct physical contact. *Standard precautions* - **Standard precautions** involve basic infection prevention practices applied to all patient encounters, such as **hand hygiene** and use of **personal protective equipment (PPE)** depending on anticipated exposure. - While always necessary, they are insufficient alone for preventing the spread of diseases transmitted via droplets, which require additional measures like **masking** for close contact.

Question 276: Isolation is useful for -

A. Diphtheria
B. Hepatitis A
C. Typhoid
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - **Isolation** is a critical infection control measure used to separate sick individuals from healthy ones to prevent disease transmission. - For diseases like **diphtheria**, **hepatitis A**, and **typhoid**, which are contagious, isolating infected patients helps limit the spread of pathogens. *Diphtheria* - **Diphtheria** is a highly contagious bacterial infection primarily transmitted through respiratory droplets. - **Isolation** of infected individuals is essential to prevent transmission to susceptible contacts. *Hepatitis A* - **Hepatitis A** is a viral liver infection spread mainly through the fecal-oral route, often via contaminated food or water. - **Isolation** is important, especially in settings with poor hygiene, to prevent further spread. *Typhoid* - **Typhoid fever** is caused by *Salmonella Typhi* and is transmitted through contaminated food and water. - **Isolation** of infected individuals, particularly those who are carriers, is crucial to prevent outbreaks.

Question 277: Under RNTCP sputum sample slide with 3 AFB per oil immersion field will be reported as:

A. ++ (2+) (Correct Answer)
B. + (1+)
C. Scanty
D. +++ (3+)

Explanation: **++ (2+)** - According to the Revised National Tuberculosis Control Programme (RNTCP) guidelines, a sputum smear with 1-10 **Acid-Fast Bacilli (AFB)** per oil immersion field is graded as **2+**. - This categorization helps in assessing the **bacterial load** and guiding treatment decisions in tuberculosis management. *+ (1+)* - This grading is used for sputum smears where 10-99 AFB are found in 100 oil immersion fields. - This is a lower bacillary load than observed in the given scenario, which implies a higher concentration of AFB per field. *Scanty* - The "scanty" category is applied when 1-9 AFB are found in 100 oil immersion fields. - The question describes finding 3 AFB per oil immersion field, indicating a much higher concentration than what would be considered "scanty." *+++ (3+)* - A 3+ grading is assigned when more than 10 AFB are seen per oil immersion field. - The presence of only 3 AFB per field falls below this threshold for a 3+ classification.

Question 278: Which disease doesn't require chemoprophylaxis?

A. Cholera
B. Measles
C. Conjunctivitis (Correct Answer)
D. Malaria

Explanation: ***Conjunctivitis*** - **Viral conjunctivitis** (most common form) is **self-limiting** and does **not require chemoprophylaxis** for contacts - Management focuses on **hygiene measures** and supportive care rather than antibiotic prophylaxis - Even bacterial conjunctivitis does not routinely warrant chemoprophylaxis for contacts; treatment is reserved for **active cases only** - Unlike other infectious diseases, conjunctivitis transmission control relies on **hand hygiene and isolation precautions** rather than drug prophylaxis *Measles* - **Post-exposure prophylaxis** with **MMR vaccine within 72 hours** or **immune globulin (IVIG) within 6 days** is recommended for susceptible contacts, especially high-risk individuals (infants, immunocompromised, pregnant women) - While technically immunoprophylaxis rather than chemoprophylaxis, measles does have **active prophylactic interventions** for exposed contacts *Cholera* - **Chemoprophylaxis with antibiotics** (doxycycline or azithromycin) is recommended for **household contacts** and close contacts of cholera cases - Used in outbreak settings to reduce transmission and prevent secondary cases in high-risk populations *Malaria* - **Chemoprophylaxis is standard practice** for travelers to endemic areas using antimalarial drugs (mefloquine, doxycycline, atovaquone/proguanil) - Essential for preventing potentially fatal infection in non-immune individuals visiting malaria-endemic regions

Question 279: All are mosquito-borne diseases EXCEPT

A. Yellow fever
B. Tularemia
C. Dengue fever
D. Kala- azar (Correct Answer)

Explanation: ***Kala-azar*** - Kala-azar, or **visceral leishmaniasis**, is caused by **Leishmania parasites** and is transmitted by the bite of infected **sandflies** (Phlebotomus species). - Sandflies, though insects, are **distinct from mosquitoes** and belong to a different family (Psychodidae). - This is **NOT a mosquito-borne disease**. *Tularemia* - Tularemia, also known as **rabbit fever**, is a disease caused by the bacterium **Francisella tularensis**. - While primarily transmitted through contact with infected animals, **ticks**, and **deer flies**, mosquitoes can rarely transmit the disease. - It can be considered mosquito-borne in rare instances. *Yellow fever* - Yellow fever is a viral disease primarily transmitted to humans through the bites of infected **Aedes** and **Haemagogus** species mosquitoes. - These mosquitoes are prevalent in tropical and subtropical regions of Africa and South America. *Dengue fever* - Dengue fever is a viral infection transmitted to humans by the bite of infected female **Aedes aegypti** or **Aedes albopictus** mosquitoes. - These mosquitoes also transmit Zika, chikungunya, and yellow fever viruses.

Question 280: Western equine encephalitis virus is transmitted by-

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

Explanation: ***Culex mosquito*** - **Western equine encephalitis** virus is primarily transmitted by **Culex mosquitoes**, particularly *Culex tarsalis* in North America. - These mosquitoes acquire the virus from infected **birds**, which act as reservoir hosts, and then transmit it to humans and horses. *Anopheles mosquito* - **Anopheles mosquitoes** are the primary vectors for **malaria**, caused by *Plasmodium* parasites. - They are not known to transmit arboviruses like the Western equine encephalitis virus. *Aedes mosquito* - **Aedes mosquitoes**, particularly *Aedes aegypti* and *Aedes albopictus*, are vectors for diseases such as **dengue**, **Zika**, **yellow fever**, and **chikungunya**. - They are not a significant vector for Western equine encephalitis. *Sandfly* - **Sandflies** (e.g., *Phlebotomus* and *Lutzomyia* species) are known vectors for **leishmaniasis** and **sandfly fever** viruses. - They do not transmit arboviruses like Western equine encephalitis.

Practice by Chapter

Communicable Disease Control Principles

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Vector-Borne Diseases

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Water-Borne Diseases

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Air-Borne Diseases

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Zoonotic Diseases

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Sexually Transmitted Infections

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HIV/AIDS Control Program

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Tuberculosis Control

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Leprosy Elimination

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Emerging and Re-emerging Infections

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Hospital-Acquired Infections

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Integrated Disease Surveillance Project

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