Infectious Diseases Practice Questions

Q: In the National Malaria Control Programme, Indoor Residual Spray (IRS) is the primary method of vector control in rural setting. Which one of the following is the 'insecticide of choice'?

Synthetic pyrethroid. ***Synthetic pyrethroid*** - **Synthetic pyrethroids** are the **insecticide of choice** for Indoor Residual Spraying (IRS) in many national malaria control programs due to their **rapid knockdown effect** and good residual activity. - They are effective against various mosquito species and have a **relatively low toxicity** to humans at recommended concentrations. *Temephos* - **Temephos** is primarily used as a **larvicide**, often applied to waterbodies to control mosquito larvae. - It is **not suitable for IRS** as it lacks the necessary residual effect on surfaces to control adult mosquitoes effectively. *DDT* - **DDT** was historically a very effective insecticide for malaria control but is now **restricted or banned** in many countries due to its **environmental persistence** and potential health concerns. - While still used in some specific contexts, it is generally **not the primary insecticide of choice** for new or ongoing programs due to these restrictions and growing **insecticide resistance**. *Malathion* - **Malathion** is an **organophosphate insecticide** that can be used for IRS, but it generally has a **shorter residual effect** compared to synthetic pyrethroids. - It may also have issues with **odor** and require more frequent reapplication, making it a less preferred option than pyrethroids in many programs.

Q: Consider the following statements regarding Kyasanur Forest Disease (KFD): 1. It is transmitted by ticks. 2. It was originally called 'pig disease' because of the association with dead pigs. 3. It was first recognized in Karnataka State. How many of the statements given above are correct?

Only two of the statements. ***Only two of the statements*** - Statement 1 is **correct**: KFD is a **tick-borne viral hemorrhagic fever**, primarily transmitted by infected *Haemaphysalis spinigera* ticks - Statement 3 is **correct**: KFD was first identified in the **Kyasanur Forest of Karnataka, India** in 1957 - Statement 2 is **incorrect**: KFD was originally called **'monkey disease' or 'monkey fever'**, not 'pig disease', because of its strong association with **monkey deaths** which serve as an early warning sign *All the three statements* - Incorrect because Statement 2 is false - the disease was associated with monkeys, not pigs *None of the statements* - Incorrect because statements 1 and 3 are both factually accurate regarding **tick-borne transmission** and **geographical origin in Karnataka** *Only one of the statements* - Incorrect because two statements (1 and 3) are correct, not just one

Q: Consider the following statements regarding dengue : 1. The mosquito becomes infective after an extrinsic incubation period of 8-10 days. 2. Once it becomes infective, the mosquito remains infective for life. 3. The genital tract of the mosquito does not get infected. Which of the statements given above are correct?

1 and 2 only. ***1 and 2 only*** - The **extrinsic incubation period** for dengue in mosquitoes (Aedes aegypti and Aedes albopictus) is indeed **8-10 days** at optimal temperatures, after which the mosquito becomes infective. - Once infected, the mosquito's salivary glands harbor the virus, making it capable of transmitting dengue for the **rest of its life**. *2 and 3 only* - While statement 2 is correct, statement 3 is incorrect. The **genital tract of the mosquito can be infected**; vertical transmission (from infected female mosquito to offspring via eggs) is a known but less common route of spread. *1 and 3 only* - Statement 1 is correct, but statement 3 is incorrect as the **genital tract can be infected**, leading to vertical transmission in mosquitoes. *1, 2 and 3* - This option is incorrect because statement 3 is false. The dengue virus can infect the **genital tract** of the mosquito, allowing for **vertical transmission** to its offspring.

Q: Consider the following : 1. Land filling for source reduction. 2. Vaccination of pigs in the risk area. 3. Immunization of children in risk area. Which of the above are the recommended control strategies for Japanese Encephalitis ?

2 and 3 only. ***2 and 3 only*** - **Immunization of children** in risk areas is the **primary recommended control strategy** for Japanese Encephalitis, as children are particularly vulnerable to severe encephalitis and long-term neurological sequelae from JEV infection. Human vaccination is endorsed by WHO and forms the backbone of JE control programs. - **Vaccination of pigs**: While pigs act as **amplifying hosts** for JEV, **pig vaccination is NOT routinely recommended** by WHO or most national programs due to practical challenges (high turnover of pig populations, cost-effectiveness issues). However, some older guidelines and regional programs have included this as a supplementary strategy in specific contexts. *1 only* - **Landfilling for source reduction** is a method for **solid waste disposal** and is NOT a recommended strategy for Japanese Encephalitis control. - JE vectors (**Culex tritaeniorhynchus mosquitoes**) breed primarily in **rice paddies, irrigation channels, and stagnant water bodies**, not in areas affected by solid waste. - Appropriate environmental management would focus on **water management** in agricultural areas, not landfilling. *1, 2 and 3* - This option incorrectly includes **landfilling**, which is not a recognized JE control strategy. - Landfilling does not target the breeding sites of Culex mosquitoes that transmit JE. *1 and 2 only* - This option incorrectly includes **landfilling** and critically omits **human immunization**, which is the most important and universally recommended control measure. - Human vaccination provides direct protection and is the cornerstone of JE prevention in endemic areas.

Q: Diethyltoluamide is an effective :

Repellent. ***Repellent*** - **Diethyltoluamide (DEET)** is a highly effective and widely used **insect repellent**. - It works by creating an olfactory barrier that deters mosquitoes and other biting insects. *Agent against propagation of Anopheles* - While DEET can prevent bites from **Anopheles mosquitoes**, it doesn't directly target their reproduction or population growth. - Measures against propagation typically involve **larvicides**, habitat modification, or insecticidal spraying. *Space spray* - **Space sprays** are designed to kill insects in an area, often using insecticides like pyrethroids, rather than repelling them from an individual. - DEET's mechanism is to deter insects from landing on skin or clothing, not to kill them in an open space. *Larvicide* - **Larvicides** are chemical or biological agents used to kill insect larvae, particularly mosquito larvae, in aquatic breeding sites. - DEET is applied to the skin or clothing to prevent adult insect bites and does not act on larvae.

Q: Mansonioides mosquito transmits the following disease :

Brugian filariasis. ***Brugian filariasis*** - **Mansonioides mosquitoes** are the primary vectors for **Brugian filariasis**, caused by **Brugia malayi** and **Brugia timori**. - This form of filariasis is characterized by **lymphatic obstruction** and **elephantiasis**, predominantly affecting the limbs. *Dengue* - **Dengue** is a viral disease transmitted exclusively by **Aedes mosquitoes**, particularly **Aedes aegypti** and **Aedes albopictus**. - Symptoms include severe fever, headache, retro-orbital pain, muscle and joint pains, and a characteristic skin rash. *Bancroftian filariasis* - **Bancroftian filariasis**, caused by **Wuchereria bancrofti**, is primarily transmitted by **Culex** (e.g., *Culex quinquefasciatus*) and sometimes **Anopheles** or **Aedes mosquitoes**. - While leading to similar lymphatic complications as Brugian filariasis, its vector species differ from Mansonioides. *Malaria* - **Malaria** is transmitted solely by **Anopheles mosquitoes**, which carry the **Plasmodium parasite**. - The disease is characterized by recurring fever, chills, and flu-like symptoms, and can be life-threatening.

Q: The most sensitive index for surveillance of malaria transmission is :

Spleen rate. ***Spleen rate*** - The **spleen rate** (percentage of children 2-9 years old with palpable splenomegaly) is the most sensitive and cost-effective index for **long-term surveillance of malaria transmission**, particularly in endemic areas. - An enlarged spleen is a common manifestation of **chronic malaria infection**, reflecting repeated exposure and immune response. *Infant parasite rate* - While helpful, the **infant parasite rate**, which measures parasites in infants, may not capture the full burden of transmission across all age groups or long-term trends. - It primarily indicates **recent or ongoing transmission** affecting the most vulnerable population. *Parasite density index* - **Parasite density index** is a measure of the number of parasites per unit volume of blood in infected individuals. - It is crucial for assessing **individual infection severity** and drug efficacy but is less suitable as a sole population-level surveillance tool for overall transmission dynamics. *Proportional case rate* - The **proportional case rate** measures the proportion of all reported cases that are malaria-related. - This index is influenced heavily by **diagnosis and reporting biases** and may not accurately reflect true transmission intensity.

Q: One of the following diseases has more than one route of transmission :

Influenza. ***Influenza*** - Influenza is primarily transmitted through **respiratory droplets** produced when an infected person coughs or sneezes. - It can also be spread by touching contaminated surfaces with the virus and then touching one's **mouth, nose, or eyes**. *Leprosy* - Leprosy is primarily transmitted through **prolonged, close contact** with an infected individual who is not undergoing treatment, via respiratory droplets from the nose and mouth. - It is not known to be transmitted through multiple, distinct routes beyond this **respiratory droplet transmission**. *Cholera* - Cholera is exclusively transmitted through the **fecal-oral route**, typically by consuming water or food contaminated with *Vibrio cholerae* bacteria. - There is no evidence of routine transmission via **respiratory droplets** or direct contact among humans. *Typhoid fever* - Typhoid fever is primarily transmitted via the **fecal-oral route**, through contaminated food or water with *Salmonella Typhi*. - While it has a single route of transmission, the means of contamination can vary, e.g., via **contaminated food handlers** or **poor sanitation**.

Q: Universal precautions to be followed by the surgical team include all of the following except :

Prophylactic antimicrobials. **Prophylactic antimicrobials** - **Prophylactic antimicrobials** are given to prevent surgical site infections and are not considered a part of **universal precautions** themselves. - Universal precautions are primarily focused on preventing the transmission of bloodborne pathogens through physical barriers. *Wearing boots* - **Wearing boots** or shoe covers is an important component of **universal precautions** in the operating room to protect against splashes and contamination from blood and body fluids. - They also help maintain a sterile environment by preventing the introduction of contaminants from street shoes. *Wearing double gloves* - **Wearing double gloves** offers an extra layer of protection against sharps injuries and potential exposure to blood and body fluids, especially during procedures with a higher risk of puncture. - This practice reinforces the **barrier protection** aspect of universal precautions. *Donning water repellent gown* - A **water-repellent gown** acts as a crucial barrier to protect the surgical team's skin and clothing from contamination with blood, body fluids, and other potentially infectious materials. - This aligns with the principle of **universal precautions** to minimize exposure risks.

Question 1

In the National Malaria Control Programme, Indoor Residual Spray (IRS) is the primary method of vector control in rural setting. Which one of the following is the 'insecticide of choice'?

Accepted Answer

Synthetic pyrethroid

Answer

Temephos

Answer

DDT

Answer

Malathion

Question 2

Raju, a 6-year-old boy, was returning home from school. At the gate, he was scratched by a dog and there was some bleeding from the wound. Which option should be followed for the post-exposure prophylaxis?

Accepted Answer

Wash the wound, vaccinate with ARV and administer immunoglobulin

Answer

Wash the wound and vaccinate with ARV only

Answer

Wash and apply antiseptic to the wound

Answer

Wash the wound and administer a shot of tetanus toxoid

Question 3

Consider the following statements regarding Kyasanur Forest Disease (KFD):

1. It is transmitted by ticks.
2. It was originally called 'pig disease' because of the association with dead pigs.
3. It was first recognized in Karnataka State.

How many of the statements given above are correct?

Accepted Answer

Only two of the statements

Answer

All the three statements

Answer

None of the statements

Answer

Only one of the statements

Question 4

Consider the following statements regarding dengue :

1. The mosquito becomes infective after an extrinsic incubation period of 8-10 days.
2. Once it becomes infective, the mosquito remains infective for life.
3. The genital tract of the mosquito does not get infected. Which of the statements given above are correct?

Accepted Answer

1 and 2 only

Answer

2 and 3 only

Answer

1 and 3 only

Answer

1, 2 and 3

Question 5

Consider the following :

1. Land filling for source reduction.
2. Vaccination of pigs in the risk area.
3. Immunization of children in risk area. Which of the above are the recommended control strategies for Japanese Encephalitis ?

Accepted Answer

2 and 3 only

Answer

1 only

Answer

1, 2 and 3

Answer

1 and 2 only

Question 6

Diethyltoluamide is an effective :

Accepted Answer

Repellent

Answer

Agent against propagation of Anopheles

Answer

Space spray

Answer

Larvicide

Question 7

Mansonioides mosquito transmits the following disease :

Accepted Answer

Brugian filariasis

Answer

Dengue

Answer

Bancroftian filariasis

Answer

Malaria

Question 8

The most sensitive index for surveillance of malaria transmission is :

Accepted Answer

Spleen rate

Answer

Infant parasite rate

Answer

Parasite density index

Answer

Proportional case rate

Question 9

One of the following diseases has more than one route of transmission :

Accepted Answer

Influenza

Answer

Leprosy

Answer

Cholera

Answer

Typhoid fever

Question 10

Universal precautions to be followed by the surgical team include all of the following except :

Accepted Answer

Prophylactic antimicrobials

Answer

Wearing boots

Answer

Wearing double gloves

Answer

Donning water repellent gown

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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