UPSC-CMS 2016 - Community Medicine Practice Questions

Q: With reference to dengue virus, consider the following statements: 1. In India, all the four serotypes are found. 2. The reservoir of infection is both man and mosquito. 3. Adults usually have a milder disease than children. 4. Dengue hemorrhagic fever is caused by infection with more than one dengue virus. Which of the statements given above is/are correct?

1, 2 and 4. ***1, 2 and 4*** - **All four serotypes** (DEN-1, DEN-2, DEN-3, and DEN-4) of the dengue virus are endemic in India, contributing to the recurrent outbreaks seen across the country. - Dengue is a **vector-borne disease**, meaning the virus cycles between humans (the primary reservoir) and mosquitoes (specifically *Aedes aegypti* and *Aedes albopictus*), making both essential for its transmission. - **Dengue hemorrhagic fever (DHF)**, or severe dengue, is often associated with a **second infection by a different serotype** of the dengue virus due to antibody-dependent enhancement (ADE). *2, 3 and 4* - The statement that adults usually have a milder disease than children is **incorrect**; children often present with milder, non-specific symptoms, while adults are more likely to develop typical dengue fever or severe forms. - The other statements regarding the presence of all four serotypes, the reservoir, and the cause of DHF are correct. *4 only* - While statement 4 (DHF caused by infection with more than one serotype) is correct, it overlooks the accuracy of statements 1 and 2. - Omitting statements 1 and 2 makes this option incomplete as both are established facts about dengue. *1 and 2 only* - This option correctly identifies that all four serotypes exist in India and that humans and mosquitoes serve as reservoirs. - However, it **incorrectly excludes statement 4** regarding the etiology of dengue hemorrhagic fever (DHF), which results from sequential infection with a different serotype.

Q: What is the window period for HIV infection?

6 – 24 weeks. ***6 – 24 weeks*** - The **window period** for HIV infection refers to the time after initial infection during which **antibodies have not yet developed** to a detectable level. - While it can vary depending on the testing method, the **6-24 week range** generally encompasses the period for traditional antibody tests to become positive. - This is the **conservative estimate** used for conventional HIV antibody testing, ensuring adequate time for seroconversion in most individuals. *3 – 6 weeks* - While many individuals will develop detectable antibodies within this timeframe, this range is **too narrow** to capture all cases of seroconversion. - Some individuals may take longer (up to 12 weeks or more) to develop detectable antibody levels, making this an **incomplete window period**. - The 6-24 week range provides a more **conservative and comprehensive** testing window. *3 – 15 days* - This timeframe is typically **too short** for the body to produce a detectable antibody response to HIV. - **Early HIV infection** during this period would likely be detected by more sensitive tests, such as **HIV RNA PCR**, which detect viral genetic material directly. - This represents the **eclipse period** rather than the full antibody window period. *6 – 8 months* - While some individuals may take longer to seroconvert, 6-8 months is generally considered **outside the typical window period** for most conventional HIV antibody tests. - Most people will develop detectable antibodies much earlier than this, usually within **3-12 weeks**. - This timeframe is excessively long and not reflective of standard testing protocols.

Q: Consider the following: 1. Skin 2. Water 3. Faeces 4. Urine Bleaching powder can be used for disinfection of which of the above?

2, 3 and 4. ***2, 3 and 4*** - **Bleaching powder** (calcium hypochlorite) is a strong oxidizing agent widely used for **disinfection** in public health. - It is highly effective for **water purification** (chlorination of drinking water and wells), **faeces disinfection** (in latrines and for controlling fecal-oral disease transmission), and **urine disinfection** (in urinals and public sanitation facilities). - These are the **standard applications** of bleaching powder in community medicine and environmental health. *1, 2 and 3* - While bleaching powder is effective for **water** and **faeces** disinfection, it is **NOT recommended for skin disinfection**. - Bleaching powder is a **strong irritant** that can cause chemical burns and skin damage. - **Skin antisepsis** requires gentler agents like alcohol, chlorhexidine, or povidone-iodine—not bleaching powder. *2 and 3 only* - This option correctly includes **water** and **faeces** disinfection. - However, it incorrectly omits **urine**, which is also routinely disinfected with bleaching powder in latrines, urinals, and sanitation systems for **odor control** and **pathogen elimination**. *1 and 2 only* - This option incorrectly includes **skin**, which should not be disinfected with bleaching powder due to its caustic nature. - It also omits both **faeces** and **urine**, which are major applications of bleaching powder in environmental health and sanitation.

Question 1

With reference to dengue virus, consider the following statements:

1. In India, all the four serotypes are found.
2. The reservoir of infection is both man and mosquito.
3. Adults usually have a milder disease than children.
4. Dengue hemorrhagic fever is caused by infection with more than one dengue virus. Which of the statements given above is/are correct?

Accepted Answer

1, 2 and 4

Answer

2, 3 and 4

Answer

4 only

Answer

1 and 2 only

Question 2

What is the window period for HIV infection?

Accepted Answer

6 – 24 weeks

Answer

3 – 6 weeks

Answer

3 – 15 days

Answer

6 – 8 months

Question 3

Consider the following:

1. Skin

2. Water

3. Faeces

4. Urine
Bleaching powder can be used for disinfection of which of the above?

Accepted Answer

2, 3 and 4

Answer

1, 2 and 3

Answer

2 and 3 only

Answer

1 and 2 only

UPSC-CMS 2016 — Community Medicine