Infectious Diseases Practice Questions

Q: Diseases spread by the shown vector are all except

Chagas disease. ***Chagas disease*** - Chagas disease is caused by *Trypanosoma cruzi* and is transmitted by the **reduviid bug** (kissing bug), not the **sandfly** shown in the image. - Its transmission involves the bug's feces, which contain trypomastigotes, entering the bite wound or mucous membranes. *Oriental sore* - This is a localized form of **cutaneous leishmaniasis**, caused by *Leishmania tropica* or *L. major*, and is transmitted by the **sandfly**. - It presents as chronic skin ulcers, primarily in the Middle East and Asia. *Cutaneous leishmaniasis* - This is a general term for various skin manifestations of leishmaniasis, including Oriental sore, which are all transmitted by the bite of an infected female **sandfly**. - It results in skin lesions ranging from nodules to ulcers. *Kala-azar* - Also known as **visceral leishmaniasis**, it is caused by *Leishmania donovani* and is transmitted by the bite of an infected female **sandfly**. - This severe form affects internal organs like the spleen, liver, and bone marrow, leading to fever, weight loss, and anemia.

Q: N95 mask is used for:

aerosol. ***aerosol*** - **N95 masks** are specifically designed to filter out at least 95% of **airborne particles** (aerosols) 0.3 microns or larger. - This level of filtration is crucial for protecting against diseases transmitted via **aerosolized droplets**, such as tuberculosis or COVID-19. *respiratory droplets* - While an N95 mask can filter respiratory droplets, it is primarily designed for smaller **aerosol particles** that can remain suspended in the air. - **Surgical masks** are generally adequate for blocking larger respiratory droplets, preventing splash and splatter. *Dust* - While an N95 mask can filter dust, it is an **overkill** for most common dust exposures. - A simple **dust mask** or even a surgical mask can provide adequate protection against larger dust particles. *in general* - This option is too broad; N95 masks are specifically used when there's a risk of exposure to **aerosolized infectious agents** or **fine particulate matter**. - Their use is typically reserved for settings where **aerosol-generating procedures** are performed or when caring for patients with **airborne diseases**.

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

Mass mebendazole treatment. ***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.

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

Zooanthroponosis. ***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.

Q: Isolation is useful for -

All of the options. ***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.

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

++ (2+). **++ (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.

Q: Which disease doesn't require chemoprophylaxis?

Conjunctivitis. ***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

Q: All are mosquito-borne diseases EXCEPT

Kala- azar. ***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.

Q: Western equine encephalitis virus is transmitted by-

Culex mosquito. ***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.

Question 1

Diseases spread by the shown vector are all except

Accepted Answer

Chagas disease

Answer

Oriental sore

Answer

Kala azar

Answer

Cutaneous leishmaniasis

Question 2

N95 mask is used for:

Accepted Answer

aerosol

Answer

respiratory droplets

Answer

Dust

Answer

in general

Question 3

Which of the following is not helpful in preventing dracunculiasis?

Accepted Answer

Mass mebendazole treatment

Answer

Filtering of drinking water

Answer

Education regarding water hygiene

Answer

Active search for new cases

Question 4

Infections which are transmitted from man to vertebrate animals are called?

Accepted Answer

Zooanthroponosis

Answer

Amphixenosis

Answer

Anthropozoonosis

Answer

Enzootics

Question 5

Isolation is useful for -

Accepted Answer

All of the options

Answer

Diphtheria

Answer

Hepatitis A

Answer

Typhoid

Question 6

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

Accepted Answer

++ (2+)

Answer

+ (1+)

Answer

Scanty

Answer

+++ (3+)

Question 7

Which disease doesn't require chemoprophylaxis?

Accepted Answer

Conjunctivitis

Answer

Cholera

Answer

Measles

Answer

Malaria

Question 8

Tuberculosis control is achieved when -

Accepted Answer

Prevalence of natural infection in 0-14 years is <1%

Answer

Annual infection rate <5%

Answer

Prevalence of natural infection in age group 0-14 years is in order of 10%

Answer

Tuberculosis conversion index in infants is <1%

Question 9

All are mosquito-borne diseases EXCEPT

Accepted Answer

Kala- azar

Answer

Yellow fever

Answer

Tularemia

Answer

Dengue fever

Question 10

Western equine encephalitis virus is transmitted by-

Accepted Answer

Culex mosquito

Answer

Anopheles mosquito

Answer

Aedes mosquito

Answer

Sandfly

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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