UPSC-CMS 2023 - Community Medicine Practice Questions

Q: In which one of the following diseases are the source of infection and reservoir of infection the same ?

Hookworm infection. ***Hookworm infection*** - In hookworm infection, the **infected human host** is considered both the **source** and **reservoir** of infection in the epidemiological chain. - The adult worms live in the **human intestine** (reservoir), and humans excrete eggs in feces that contaminate soil, where larvae develop and subsequently infect other humans, perpetuating the cycle within the human population. - While larvae develop in soil, the **ultimate source and reservoir is the infected human**, as without human hosts, the transmission cycle cannot be maintained. *Tetanus* - The **reservoir** for tetanus is **soil and the gastrointestinal tract of animals**, where *Clostridium tetani* spores persist. - The **source of infection** is contaminated soil or rusty objects entering wounds. - Humans are **accidental hosts** (dead-end hosts) and do not serve as reservoirs, so source and reservoir are distinct (both environmental). *Cholera* - The **reservoir** for cholera is primarily **humans**, with *Vibrio cholerae* colonizing the intestinal tract. - The **source of infection** is typically **water or food contaminated with feces** from infected individuals. - While humans are the main reservoir, aquatic environments can serve as secondary environmental reservoirs, and the immediate source (contaminated water/food) is often considered distinct from the human reservoir in classical teaching. *Typhoid* - The **reservoir** for typhoid is exclusively **humans**, particularly chronic carriers who harbor *Salmonella typhi* in the gallbladder. - The **source of infection** is **food or water contaminated** by infected human carriers. - Although humans are the sole reservoir, the immediate source (contaminated food/water) is conventionally distinguished from the reservoir (the carrier), making them technically distinct in the transmission chain.

Q: Which of the following statements are correct regarding Chikungunya fever ? 1. It is usually transmitted by Culex mosquito. 2. A safe and effective vaccine is available for commercial use. 3. Incubation period is 4 - 7 days. 4. One of the prominent symptoms is arthropathy. Select the correct answer using the code given below :

3 and 4 only. ***3 and 4 only*** - The incubation period for Chikungunya fever is typically **3-7 days**, with a range of 2-12 days, making 4-7 days a correct estimate. - **Arthropathy** (severe joint pain and swelling) is a hallmark symptom of Chikungunya fever, often presenting with polyarthralgia that can be debilitating and chronic. *1 and 4 only* - Chikungunya fever is primarily transmitted by **Aedes mosquitoes** (Aedes aegypti and Aedes albopictus), not Culex mosquitoes. - While arthropathy (statement 4) is a correct symptom, the transmission by Culex mosquito (statement 1) is incorrect. *2 and 3 only* - As of now, there is **no commercially available safe and effective vaccine** for Chikungunya fever, although several are in clinical trials. - While the incubation period (statement 3) is correct, the absence of a commercially available vaccine (statement 2) makes this option incorrect. *1 and 2 only* - Chikungunya is transmitted by **Aedes mosquitoes**, not Culex mosquitoes. - There is currently **no licensed vaccine** for Chikungunya available for widespread commercial use.

Q: In which one of the following diseases, the transmission chain is 'Man-Snail-Man' ?

Schistosomiasis. ***Schistosomiasis*** - The transmission cycle for **schistosomiasis** involves humans as the definitive host and **snails** as the intermediate host. - Eggs are passed in human feces or urine, hatch in freshwater to **miracidia**, which then infect snails. Snails release **cercariae** that penetrate human skin, completing the 'Man-Snail-Man' chain. *Malaria* - The transmission chain for **malaria** is typically 'Man-Mosquito-Man', where Anopheles mosquitoes serve as the vector. - There is no involvement of **snails** in the life cycle of the Plasmodium parasite. *Onchocerciasis* - **Onchocerciasis**, or river blindness, is transmitted by the bite of infected blackflies (Simulium species). - The life cycle involves microfilariae maturing into adult worms in the human host, with blackflies as the **arthropod vector**. *Fish tapeworm* - The **fish tapeworm (Diphyllobothrium latum)** has a complex life cycle involving copepods (crustaceans) and fish as intermediate hosts. - Humans become infected by consuming raw or undercooked infected fish, not through **snail** involvement.

Q: Which of the following mosquito-borne diseases are transmitted chiefly by Aedes mosquito ? 1. Dengue 2. West Nile fever 3. Yellow fever 4. Zika fever Select the correct answer using the code given below :

1, 3 and 4. ***1, 3 and 4*** - **Dengue**, **Yellow fever**, and **Zika fever** are all primarily transmitted by the *Aedes* mosquito, especially *Aedes aegypti* and *Aedes albopictus*. - These mosquitoes are known for biting during the day and thrive in urbanized environments. *1 and 3 only* - This option is incomplete as **Zika fever** is also transmitted by *Aedes* mosquitoes. - Excluding Zika fever makes this option incorrect, as Zika's primary vector is well-established as *Aedes*. *1, 2 and 3* - **West Nile fever** is primarily transmitted by *Culex* mosquitoes, not *Aedes*. - Therefore, its inclusion invalidates this option because *Aedes* is not the chief vector for West Nile fever. *2 and 4 only* - This option is incorrect because **West Nile fever** is not primarily transmitted by *Aedes* mosquitoes. - Moreover, it omits **Dengue** and **Yellow fever**, which are classic examples of *Aedes*-borne diseases.

Q: Consider the following vaccines : 1. BCG Vaccine 2. Hepatitis B Vaccine 3. Inactivated Polio Vaccine (IPV) 4. Oral Polio Vaccine (OPV) What is the correct order of the above vaccines as per their sensitivity to heat (most sensitive to least sensitive) given in the National Immunization Schedule (NIS) ?

4→3→2→1. ***4→3→2→1 (OPV → IPV → Hepatitis B → BCG)*** * **Oral Polio Vaccine (OPV)** is the **most heat-sensitive** vaccine among these options. As a live attenuated viral vaccine, it requires storage at -20°C (freezer storage) and is extremely thermolabile, necessitating the strictest cold chain management with VVM monitoring. * **Inactivated Polio Vaccine (IPV)** is the second most heat-sensitive vaccine, requiring refrigeration at 2-8°C. While more stable than OPV due to inactivation, it remains highly sensitive to heat exposure and requires careful cold chain maintenance. * **Hepatitis B Vaccine** has moderate heat sensitivity. As a recombinant subunit vaccine, it requires storage at 2-8°C but is more thermostable than the polio vaccines. It can tolerate brief temperature excursions better than live attenuated vaccines. * **BCG Vaccine** is the **least heat-sensitive** among these four vaccines, though it still requires proper cold chain management at 2-8°C. While BCG is light-sensitive, it demonstrates relatively better heat stability compared to OPV, IPV, and Hepatitis B vaccines in field conditions per National Immunization Schedule guidelines. *Incorrect Option 2→1→3→4* - Incorrectly places Hepatitis B as most sensitive when OPV is actually most thermolabile *Incorrect Option 2→3→1→4* - Wrong order placing Hepatitis B first instead of OPV *Incorrect Option 3→1→4→2* - Incorrectly suggests IPV is most sensitive and has an inaccurate sequence

Q: Exposure to gases is a common hazard in industries. The gases can be classified as simple asphyxiants, chemical asphyxiants and anaesthetic gases. Which among the following are chemical asphyxiating gases ? 1. Carbon monoxide 2. Chloroform 3. Cyanide gas 4. Hydrogen Select the correct answer using the code given below :

1 and 3. ***1 and 3*** - Both **carbon monoxide** and **cyanide gas** are classic examples of chemical asphyxiants. - They interfere with the body's ability to utilize oxygen, leading to **cellular hypoxia** despite adequate tissue perfusion. *2 and 4* - **Chloroform** is an anesthetic and hepatotoxin, not primarily an asphyxiant. - **Hydrogen** is a simple asphyxiant but does not have the chemical asphyxiant properties of carbon monoxide or cyanide. *1 and 4* - While **carbon monoxide** is a chemical asphyxiant, **hydrogen** is a simple asphyxiant that displaces oxygen without directly interfering with cellular respiration. - The question implies a focus on gases that chemically interfere with oxygen utilization. *2 and 3* - **Cyanide gas** is an asphyxiant, but **chloroform** is an anesthetic and can cause central nervous system depression and organ toxicity. - Chloroform's mechanism of action is distinct from the cellular hypoxia caused by asphyxiants.

Q: The Employees State Insurance Act, 1948 of India provides for certain benefits to employees. Which among the following are benefits to insured persons or to other dependents under the Act ? 1. Disablement benefit 2. Funeral expenses 3. Maternity benefit 4. Travel benefit Select the correct answer using the code given below :

1, 2 and 3 only. ***1, 2 and 3 only*** - The **Employees' State Insurance Act of 1948** provides comprehensive social security benefits including **Disablement Benefit** for temporary or permanent incapacitation, **Funeral Expenses** for the deceased insured person, and **Maternity Benefit** to women. - These benefits are designed to protect employees and their dependents against various health-related and economic contingencies. *2 and 4 only* - This option is incorrect because **funeral expenses** are indeed covered, but there is no specific "travel benefit" as a standard provision under the ESI Act for insured persons or their dependents. - While medical benefits allow for treatment in ESI hospitals, a general travel benefit akin to reimbursement for personal travel is not part of the scheme. *1, 2, 3 and 4* - This option is incorrect because while **Disablement Benefit**, **Funeral Expenses**, and **Maternity Benefit** are provided, a general **Travel Benefit** is not one of the statutory benefits offered by the ESI Act. - The Act focuses on medical care, income support during sickness/maternity/disablement, and dependent support, not general travel. *1 and 3 only* - This option is incomplete as it correctly identifies **Disablement Benefit** and **Maternity Benefit** but excludes **Funeral Expenses**, which are explicitly covered as part of the benefits package under the ESI Act. - Funeral expenses provide financial support to the family of a deceased insured person to some extent.

Q: Which among the following vaccines best represent interventions that focus on cancer prevention too ? 1. Hepatitis A vaccine 2. Hepatitis B vaccine 3. Hemophilus influenzae B vaccine 4. Human papilloma virus vaccine Select the correct answer using the code given below :

2 and 4. ***2 and 4*** - The **Hepatitis B vaccine** prevents **Hepatitis B virus (HBV)** infection, which is a major risk factor for developing **hepatocellular carcinoma (HCC)**, a type of liver cancer. Vaccination significantly reduces the incidence of HBV-related liver cancer. - The **Human Papillomavirus (HPV) vaccine** protects against high-risk HPV types, which are responsible for almost all cases of **cervical cancer**, as well as many cases of anal, oropharyngeal, vaginal, and penile cancers. - Both vaccines directly prevent cancer by preventing the viral infections that cause these malignancies. *1 and 4* - The **Hepatitis A vaccine** prevents **Hepatitis A virus (HAV)** infection, which causes acute liver inflammation but is **not associated with chronic liver disease or liver cancer**. - While the **HPV vaccine** indeed prevents cancer, the inclusion of Hepatitis A vaccine makes this option incorrect for cancer prevention. *2 and 3* - The **Hepatitis B vaccine** effectively prevents liver cancer by preventing HBV infection. - The **Hemophilus influenzae B (Hib) vaccine** prevents serious infections caused by *Haemophilus influenzae* type b, such as meningitis and epiglottitis, but it has **no direct role in cancer prevention**. *1 and 2* - The **Hepatitis A vaccine** prevents HAV infection but **does not prevent cancer**. - While the **Hepatitis B vaccine** effectively prevents liver cancer, the inclusion of Hepatitis A vaccine makes this option incomplete for the best representation of cancer prevention interventions.

Question 1

In which one of the following diseases are the source of infection and reservoir of infection the same ?

Accepted Answer

Hookworm infection

Answer

Tetanus

Answer

Cholera

Answer

Typhoid

Question 2

Which of the following statements are correct regarding Chikungunya fever ?

1. It is usually transmitted by Culex mosquito.
2. A safe and effective vaccine is available for commercial use.
3. Incubation period is 4 - 7 days.
4. One of the prominent symptoms is arthropathy.

Select the correct answer using the code given below :

Accepted Answer

3 and 4 only

Answer

1 and 4 only

Answer

2 and 3 only

Answer

1 and 2 only

Question 3

In which one of the following diseases, the transmission chain is 'Man-Snail-Man' ?

Accepted Answer

Schistosomiasis

Answer

Malaria

Answer

Onchocerciasis

Answer

Fish tapeworm

Question 4

Which of the following mosquito-borne diseases are transmitted chiefly by Aedes mosquito ?

1. Dengue
2. West Nile fever
3. Yellow fever
4. Zika fever

Select the correct answer using the code given below :

Accepted Answer

1, 3 and 4

Answer

1 and 3 only

Answer

1, 2 and 3

Answer

2 and 4 only

Question 5

Consider the following vaccines :

1. BCG Vaccine
2. Hepatitis B Vaccine
3. Inactivated Polio Vaccine (IPV)
4. Oral Polio Vaccine (OPV) What is the correct order of the above vaccines as per their sensitivity to heat (most sensitive to least sensitive) given in the National Immunization Schedule (NIS) ?

Accepted Answer

4→3→2→1

Answer

2→1→3→4

Answer

2→3→1→4

Answer

3→1→4→2

Question 6

Exposure to gases is a common hazard in industries. The gases can be classified as simple asphyxiants, chemical asphyxiants and anaesthetic gases. Which among the following are chemical asphyxiating gases ?

1. Carbon monoxide

2. Chloroform

3. Cyanide gas

4. Hydrogen

Select the correct answer using the code given below :

Accepted Answer

1 and 3

Answer

2 and 4

Answer

1 and 4

Answer

2 and 3

Question 7

The Employees State Insurance Act, 1948 of India provides for certain benefits to employees. Which among the following are benefits to insured persons or to other dependents under the Act ?

1. Disablement benefit 
2. Funeral expenses 
3. Maternity benefit 
4. Travel benefit

Select the correct answer using the code given below :

Accepted Answer

1, 2 and 3 only

Answer

2 and 4 only

Answer

1, 2, 3 and 4

Answer

1 and 3 only

Question 8

Which among the following vaccines best represent interventions that focus on cancer prevention too ?

1. Hepatitis A vaccine
2. Hepatitis B vaccine
3. Hemophilus influenzae B vaccine
4. Human papilloma virus vaccine

Select the correct answer using the code given below :

Accepted Answer

2 and 4

Answer

1 and 4

Answer

2 and 3

Answer

1 and 2

Question 9

Consider the following statements:

Statement-I: While calculating the number of expected pregnancies per year in an area, a correction factor (usually 10%) is added to the expected number of live births in the year in the area.

Statement-II: All the pregnancies in the area may not be registered by the health worker in the area. Which one of the following is correct in respect of the above statements?

Accepted Answer

Statement-I and Statement-II are independently correct, but Statement-II is not a correct explanation for Statement-I.

Answer

Statement-II is incorrect but Statement-I is correct.

Answer

Statement-I is correct but Statement-II is incorrect.

Answer

Statement-I and Statement-II are independently correct, and Statement-II is a correct explanation for Statement-I.

UPSC-CMS 2023 — Community Medicine