Infectious Diseases Practice Questions

Q: Mass chemoprophylaxis in endemic areas is recommended for all of the following, except:

Leprosy. ***Leprosy*** - **Mass chemoprophylaxis** for leprosy is generally *not recommended* due to concerns about drug resistance and the long incubation period. - Instead, the focus is on **early detection** and *multi-drug therapy (MDT)* for diagnosed cases, and contact tracing with single-dose rifampicin (SDR) as post-exposure prophylaxis for close contacts in some settings. *Trachoma* - **Mass drug administration (MDA)** of *azithromycin* is a cornerstone of the **SAFE strategy** (Surgery, Antibiotics, Facial cleanliness, Environmental improvement) for eliminating trachoma, recommended in endemic areas. - This aims to reduce the community reservoir of *Chlamydia trachomatis* infection, thus preventing new infections and progression of the disease. *Yaws* - **Mass treatment programs** with a *single oral dose of azithromycin* have been highly effective and are recommended by the WHO for the eradication of yaws in endemic communities. - This strategy aims to interrupt transmission and eliminate the *Treponema pallidum subspecies pertenue* bacterium. *Filaria* - **Mass drug administration (MDA)** with anti-filarial drugs (e.g., *diethylcarbamazine and albendazole*) is a key strategy for the elimination of lymphatic filariasis in endemic areas. - MDA aims to reduce the microfilaria burden in infected individuals, thereby interrupting transmission of the parasite by mosquitoes.

Q: False about Japanese encephalitis is -

Overhead tanks serve as breeding site. ***Overhead tanks serve as breeding site*** - The primary vector for **Japanese encephalitis (JE)** is the *Culex* mosquito, which typically breeds in **rice paddies** and other ground-level water sources, not overhead tanks. - While *Culex* mosquitoes need water to breed, overhead tanks generally circulate human-used water and are not their preferred or typical breeding sites, making this statement false regarding JE transmission. *Pigs are amplifiers* - **Pigs** are known to be **amplifying hosts** for the Japanese encephalitis virus. They develop high viremia (high viral load in the blood) without becoming severely ill, allowing mosquitoes to pick up the virus from them and transmit it to other hosts. - This cycle is crucial for the maintenance and spread of the virus in endemic areas, making the statement true. *Primary dose of vaccine consists of two doses* - The **Japanese encephalitis vaccine** often requires a primary series of **two doses** for optimal protection, administered at least 28 days apart, followed by a booster dose if continued exposure is anticipated. - This regimen ensures a robust and lasting immune response against the virus, making the statement true. *Transmitted by Culex mosquitoes* - **Japanese encephalitis** is predominantly transmitted through the bite of infected **Culex mosquitoes**, particularly *Culex tritaeniorhynchus*. - These mosquitoes are ubiquitous in endemic regions of Asia and are the main vector responsible for spreading the virus between animal hosts and to humans, making the statement true.

Q: Guineaworm infestation is common in workers of:

Step wells. ***Step wells*** - **Guineaworm disease (Dracunculiasis)** is contracted by ingesting water contaminated with **Cyclops (water fleas)** that host the parasite larvae. - **Step wells** often serve as communal water sources in affected regions, making them common sites for transmission due to repeated human contact. *Fields* - Working in fields does not directly expose individuals to the contaminated water sources responsible for Guineaworm transmission. - While agricultural workers may come into contact with water, it typically isn't stagnant water containing the specific intermediate host. *Cotton mills* - Cotton mills are indoor industrial environments and do not involve exposure to freshwater sources where **Guineaworm** is commonly transmitted. - This occupation has no direct link to the lifecycle of **Dracunculus medinensis**. *Ponds* - While ponds can contain **Cyclops**, the term "ponds" is broad and doesn't specifically imply the high concentration of human activity and dependence on these sources for drinking water that **step wells** often represent in affected communities. - **Step wells** are particularly implicated due to their role as shared, often stagnant, drinking water sources in endemic areas.

Q: Lyme disease is transmitted by

Tick. ***Tick*** - Lyme disease is caused by the bacterium **_Borrelia burgdorferi_** and is primarily transmitted through the bite of infected **black-legged ticks** (also known as deer ticks). - The tick must be attached for at least 36-48 hours for the bacteria to be transmitted, leading to symptoms like a **bullseye rash (erythema migrans)**, fever, and joint pain. *Mosquito* - Mosquitoes are vectors for diseases such as **malaria**, **Dengue fever**, **Zika virus**, and **West Nile virus**, but not Lyme disease. - They transmit pathogens through their bite but are not involved in the **_Borrelia burgdorferi_** life cycle. *Mite* - Mites are responsible for diseases like **scabies** and act as vectors for scrub typhus, but they do not transmit Lyme disease. - While ticks are also arachnids like mites, they belong to different families and transmit different pathogens. *Rat flea* - Rat fleas are primarily known for transmitting **_Yersinia pestis_**, the bacterium that causes **bubonic plague**. - They are not associated with the transmission of Lyme disease.

Q: Tuberculous pericarditis is included in which treatment category of DOTS strategy?

Category I. ***Correct Option: Category I*** - **Tuberculous pericarditis** is classified as a **severe form of extra-pulmonary tuberculosis (EPTB)**. - Category I includes new cases of **smear-positive pulmonary TB**, **severe smear-negative pulmonary TB**, and **severe forms of EPTB**. - Severe EPTB includes: **TB meningitis, TB pericarditis, intestinal TB, genitourinary TB, spinal TB, and disseminated/miliary TB**. - Tuberculous pericarditis is considered severe due to potential complications like **cardiac tamponade** and **constrictive pericarditis**, requiring intensive treatment. *Incorrect Option: Category II* - Category II is reserved for **retreatment cases** including relapse, treatment failure, or treatment after default. - This is not applicable to a **newly diagnosed case** of tuberculous pericarditis. *Incorrect Option: Category III* - Category III (now largely phased out) was for **less severe forms of EPTB** such as lymph node TB or pleural TB. - Also included new smear-negative pulmonary TB without extensive involvement. - **Tuberculous pericarditis is too severe** to be classified under Category III. *Incorrect Option: Category IV* - Category IV is for **multi-drug resistant tuberculosis (MDR-TB)** and extensively drug-resistant TB (XDR-TB). - Requires specialized, longer treatment regimens. - Not applicable to drug-sensitive tuberculous pericarditis.

Q: Most common vector of Japanese encephalitis is:

Culex. **Culex** - **Culex mosquitoes**, particularly species like *Culex tritaeniorhynchus*, are the primary vectors responsible for transmitting **Japanese encephalitis virus** to humans. - These mosquitoes typically breed in stagnant water, such as rice paddies, and are most active during dusk and dawn. *Aedes* - **Aedes mosquitoes** are well-known vectors for diseases such as **dengue fever**, **Zika virus**, and **chikungunya virus**. - While they can transmit a range of arboviruses, they are not the primary vectors for Japanese encephalitis. *Anopheles* - **Anopheles mosquitoes** are the primary vectors for **malaria**, transmitting the *Plasmodium* parasite. - They are not associated with the transmission of Japanese encephalitis. *Ixodes* - **Ixodes ticks** are the primary vectors for **Lyme disease**, transmitting the bacterium *Borrelia burgdorferi*. - They are not insects and are not involved in the transmission of viral diseases such as Japanese encephalitis.

Q: After the appearance of rash, prophylactic isolation of measles case is necessary for a minimum of:

5 days. ***5 days*** - Measles patients are infectious from **4 days before** to **4 days after** the rash appears, making them infectious for approximately 8-9 days total. - Standard isolation guidelines recommend isolation for **at least 4 days after rash onset**, and the 5-day option represents a **conservative approach** ensuring complete coverage of the infectious period. - This timeframe is crucial for controlling the spread of the **highly contagious measles virus** in community and healthcare settings, and the minimum of 5 days ensures no residual transmission risk. *2 days* - Isolating for only 2 days after the rash appears is **insufficient** as the patient remains infectious for at least 4 days post-rash. - This period does not cover the full duration of infectivity, leading to potential **onward transmission** and outbreak continuation. *7 days* - While 7 days would effectively cover the infectious period, it is **longer than medically necessary** for standard measles isolation after rash onset. - This extended isolation may impose **unnecessary burden** on patients, caregivers, and healthcare facilities without additional public health benefit. *9 days* - Isolating for 9 days is **excessive** and not required for measles, as the infectivity period after rash onset ends by day 4-5. - Prolonged isolation beyond the recommended period provides **no additional public health benefit** and can have significant social, psychological, and economic impacts on patients and families.

Q: 1st case of which of the following was found in Shimoga district of Karnataka -

KFD. ***KFD*** - **Kyasanur Forest Disease (KFD)** is an endemic viral hemorrhagic fever whose first human cases were identified in the Shimoga district of Karnataka, India, in 1957. - The disease is caused by the **Kyasanur Forest disease virus (KFDV)**, a member of the *Flaviviridae* family, transmitted by ticks. *Japanese encephalitis* - While Japanese encephalitis is prevalent in parts of India, its initial discovery and identification are not associated with the Shimoga district of Karnataka. - The disease is caused by the **Japanese encephalitis virus (JEV)** and is primarily transmitted by mosquitoes. *Yellow fever* - **Yellow fever** is primarily widespread in tropical and subtropical areas of South America and Africa. - There are no historical records indicating the first case of yellow fever was discovered in the Shimoga district of Karnataka. *Dengue fever* - **Dengue fever** is a mosquito-borne tropical disease found globally, but its initial discovery is not linked to the Shimoga district of Karnataka. - Its outbreaks are common in many parts of India, but the first documented case of dengue fever did not originate there.

Q: Which of the following vectors has a habit of frequent vomiting?

House fly. ***House fly*** - The **house fly** (Musca domestica) is known for its habit of **regurgitating** its gut contents (vomiting) onto food before ingesting it, as part of a regurgitative feeding strategy. - This behavior aids in the external digestion of solid food particles into a liquid form that the fly can then suck up. *Mite* - **Mites** are typically **arachnids** and do not feed by vomiting; their feeding habits vary greatly depending on the species, but typically involve piercing and sucking fluids. - They lack the organ systems for regurgitative feeding similar to that of a house fly. *Sand flea* - **Sand fleas** (Tunga penetrans) are ectoparasites that **burrow into the skin** of their hosts, where they feed and lay eggs. - Their feeding mechanism involves piercing the host's skin to feed on blood or tissue, and they do not exhibit vomiting behavior. *Mosquito* - **Mosquitoes** are known for their **sucking mouthparts**, which they use to feed on blood or plant nectar. - While they can regurgitate saliva during feeding, this is distinct from the frequent, digestive vomiting habit of a house fly.

Q: Color of box containing drugs for treatment of category I of TB -

Red. ***Red*** - In the Revised National Tuberculosis Control Programme (RNTCP), the **red box** contains drugs for **Category I TB**, which includes new smear-positive pulmonary TB, new smear-negative pulmonary TB with extensive parenchymal involvement, and severe forms of extrapulmonary TB. - This color-coding system facilitated appropriate drug distribution and adherence to standardized treatment regimens in the category-based approach. *Yellow* - The **yellow box** in the RNTCP was designated for **Category II TB** drugs, used for retreatment cases such as relapse, treatment failure, or treatment after default. - These cases required a longer and more intensive treatment regimen with additional drugs including streptomycin in the intensive phase. *Blue* - The **blue box** contained drugs for **Category III TB**, which included new smear-negative pulmonary TB cases that did not meet Category I criteria and less severe forms of extrapulmonary TB. - This category received a shorter treatment regimen compared to Categories I and II. *Green* - Green was **not a standard color** in the RNTCP category-based treatment color-coding system. - The RNTCP primarily used red, yellow, and blue boxes for Categories I, II, and III respectively, while MDR-TB treatment followed separate protocols outside this color-coding system.

Question 1

Mass chemoprophylaxis in endemic areas is recommended for all of the following, except:

Accepted Answer

Leprosy

Answer

Trachoma

Answer

Yaws

Answer

Filaria

Question 2

False about Japanese encephalitis is -

Accepted Answer

Overhead tanks serve as breeding site

Answer

Pigs are amplifiers

Answer

Primary dose of vaccine consists of two doses

Answer

Transmitted by Culex mosquitoes

Question 3

Guineaworm infestation is common in workers of:

Accepted Answer

Step wells

Answer

Fields

Answer

Cotton mills

Answer

Ponds

Question 4

Lyme disease is transmitted by

Accepted Answer

Tick

Answer

Mosquito

Answer

Mite

Answer

Rat flea

Question 5

Tuberculous pericarditis is included in which treatment category of DOTS strategy?

Accepted Answer

Category I

Answer

Category IV

Answer

Category II

Answer

Category III

Question 6

Most common vector of Japanese encephalitis is:

Accepted Answer

Culex

Answer

Aedes

Answer

Anopheles

Answer

Ixodes

Question 7

After the appearance of rash, prophylactic isolation of measles case is necessary for a minimum of:

Accepted Answer

5 days

Answer

2 days

Answer

7 days

Answer

9 days

Question 8

1st case of which of the following was found in Shimoga district of Karnataka -

Accepted Answer

KFD

Answer

Japanese encephalitis

Answer

Yellow fever

Answer

Dengue fever

Question 9

Which of the following vectors has a habit of frequent vomiting?

Accepted Answer

House fly

Answer

Mite

Answer

Sand flea

Answer

Mosquito

Question 10

Color of box containing drugs for treatment of category I of TB -

Accepted Answer

Red

Answer

Yellow

Answer

Blue

Answer

Green

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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