Environmental Health — MCQs

Environmental Health Indian Medical PG Practice Questions and MCQs

Question 271: Which of the following is NOT spread by Aedes mosquito?

A. Dengue fever
B. Chikungunya
C. Japanese encephalitis (Correct Answer)
D. Yellow fever

Explanation: **Explanation:** The correct answer is **Japanese encephalitis (JE)** because it is transmitted by the bite of infected **Culex mosquitoes**, primarily *Culex tritaeniorhynchus* and *Culex vishnui*. These mosquitoes typically breed in stagnant water, such as rice fields and shallow ditches. **Why the other options are incorrect:** * **Dengue fever:** This is the most common viral disease transmitted by the **Aedes aegypti** (primary vector) and *Aedes albopictus* mosquitoes. * **Chikungunya:** This viral illness is also transmitted to humans by the bite of infected **Aedes aegypti** and **Aedes albopictus** mosquitoes. * **Yellow fever:** This is a viral hemorrhagic disease transmitted by **Aedes aegypti** in urban cycles and *Haemagogus* species in jungle cycles. **High-Yield Clinical Pearls for NEET-PG:** * **Aedes Characteristics:** Known as the "Tiger Mosquito" due to white stripes on its body. It is a **day-biter** (mostly early morning and late afternoon) and breeds in **artificial collections of clean water** (e.g., flower pots, discarded tires, desert coolers). * **Culex Characteristics:** Known as the "nuisance mosquito." It is a **night-biter** and breeds in **dirty/polluted water**. Besides JE, it is the vector for **Bancroftian Filariasis** and West Nile Virus. * **Anopheles:** The vector for **Malaria**; it breeds in fresh water and bites at night. * **Zika Virus:** Also transmitted by the *Aedes* mosquito.

Question 272: What is the recommended fluoride level in drinking water in ppm?

A. 0.5
B. 0.5-0.8 (Correct Answer)
C. 1.5
D. 1.1

Explanation: **Explanation:** The concentration of fluoride in drinking water is a critical public health parameter, often referred to as a "two-edged sword" because both deficiency and excess lead to pathology. **Why 0.5–0.8 ppm is correct:** According to the **World Health Organization (WHO)** and standard public health guidelines (Park’s Preventive and Social Medicine), the recommended "optimal" level of fluoride in drinking water to prevent dental caries while avoiding toxicity is **0.5 to 0.8 mg/L (ppm)**. At this concentration, fluoride promotes remineralization of enamel and inhibits bacterial metabolism without causing systemic harm. **Analysis of Incorrect Options:** * **0.5 (Option A):** While this is the lower limit of the recommended range, it is incomplete. The range 0.5–0.8 is the more precise standard for tropical climates like India. * **1.5 (Option C):** This is the **Maximum Permissible Limit** set by the WHO. Concentrations above 1.5 ppm significantly increase the risk of dental fluorosis. * **1.1 (Option D):** This value is often cited as the threshold where dental fluorosis may begin to manifest in a population, but it is not the "recommended" level for health promotion. **High-Yield Clinical Pearls for NEET-PG:** * **Dental Fluorosis:** Occurs when levels exceed **1.5 ppm**. It presents as "mottling" of teeth (Chalky white patches or brownish discoloration). * **Skeletal Fluorosis:** Occurs with prolonged exposure to levels > **3.0–6.0 ppm**. It leads to "Knock-knees" (Genu Valgum) and crippling deformities. * **Defluoridation:** The **Nalgonda Technique** (using alum, lime, and bleaching powder) is the most common method used in India to remove excess fluoride. * **Fluorine & Hardness:** Fluorosis is more severe in areas with low dietary calcium intake.

Question 273: Which of the following diseases is NOT transmitted by milk?

A. Tuberculosis
B. Brucellosis
C. Q Fever
D. Leishmaniasis (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Leishmaniasis**. **1. Why Leishmaniasis is the correct answer:** Leishmaniasis (Kala-azar) is a protozoal disease caused by *Leishmania donovani*. It is a **vector-borne disease** transmitted solely through the bite of an infected female **sandfly** (*Phlebotomus argentipes*). It is not a milk-borne pathogen because the parasite requires a specific biological cycle within the insect vector and the mammalian host's reticuloendothelial system; it cannot survive or be transmitted through ingestion of bovine milk. **2. Why the other options are incorrect:** Milk can act as a vehicle for various pathogens, categorized into those originating from the animal (endogenous) or from human handling (exogenous). * **Tuberculosis (A):** *Mycobacterium bovis* is transmitted from infected cattle to humans via raw milk, causing extrapulmonary TB (commonly abdominal). * **Brucellosis (B):** Also known as "Undulant Fever," it is primarily transmitted through the consumption of unpasteurized milk or milk products from infected cows, goats, or sheep. * **Q Fever (C):** Caused by *Coxiella burnetii*, this organism is highly heat-resistant and is excreted in the milk of infected livestock. It is the "index organism" used to set the temperature/time standards for pasteurization. **High-Yield Clinical Pearls for NEET-PG:** * **Pasteurization:** The primary aim is to kill all pathogenic bacteria, especially *M. tuberculosis* and *Brucella*. However, the **Phosphatase Test** is used to check the efficiency of pasteurization because the enzyme phosphatase is slightly more heat-resistant than these pathogens. * **Diseases transmitted via milk:** * **From Animal:** TB, Brucellosis, Q Fever, Anthrax, Cowpox. * **From Human/Environment:** Typhoid, Cholera, Dysentery, Staphylococcal food poisoning. * **Q Fever** is unique because it can be transmitted via both milk ingestion and inhalation of infected dust.

Question 274: What is the causative toxin for endemic ascites?

A. Ergot
B. Aflatoxin
C. Pyrrolizidine (Correct Answer)
D. Beta-oxylamino-alanine

Explanation: **Explanation:** **Endemic Ascites** (also known as Veno-Occlusive Disease) is a clinical condition characterized by the sudden onset of jaundice, rapidly developing ascites, and hepatomegaly. **Why Pyrrolizidine is correct:** The condition is caused by the consumption of **Pyrrolizidine alkaloids**. These toxins are found in the seeds of **Crotalaria** (locally known as *Jhunjhunia*), which often contaminate staple food crops like millet or wheat. Pathologically, these alkaloids cause the blockage of small hepatic veins (Veno-Occlusive Disease), leading to portal hypertension and massive ascites. In India, outbreaks have been historically reported in the Sarguja district of Chhattisgarh. **Why other options are incorrect:** * **Ergot:** Produced by the fungus *Claviceps purpurea* (contaminating Bajra/Rye). It causes **Ergotism**, characterized by gangrene of fingers/toes or convulsions, but not ascites. * **Aflatoxin:** Produced by *Aspergillus flavus* (contaminating groundnuts/maize). Chronic exposure is a major risk factor for **Hepatocellular Carcinoma (HCC)** and acute outbreaks cause toxic hepatitis. * **Beta-oxylamino-alanine (BOAA):** Also known as ODAP, this neurotoxin is found in *Lathyrus sativus* (Khesari Dal). It causes **Lathyrism**, a form of spastic paraplegia. **High-Yield Clinical Pearls for NEET-PG:** * **Crotalaria contamination:** Associated with "Veno-Occlusive Disease" (VOD). * **Epidemic Dropsy:** Caused by **Sanguinarine** (Argemone oil contaminating Mustard oil); characterized by bilateral pitting edema and cardiac failure. * **Aflatoxin B1:** The most potent hepatocarcinogen among aflatoxins. * **Lathyrism Prevention:** Soaking the pulse in hot water (leaching) or parboiling helps remove the BOAA toxin.

Question 275: Which of the following was the first launched program associated with rural drinking water supply?

A. Accelerated Rural Water Supply Programme (Correct Answer)
B. Rajiv Gandhi National Drinking Water Mission
C. Swajaldhara
D. Technology Mission

Explanation: **Explanation:** The provision of safe drinking water is a cornerstone of Environmental Health and Preventive Medicine, aimed at reducing the burden of water-borne diseases like Cholera, Typhoid, and Hepatitis A/E. **Why Option A is Correct:** The **Accelerated Rural Water Supply Programme (ARWSP)** was launched in **1972-73** by the Government of India. It was the **first major central intervention** designed to assist states and union territories in accelerating the coverage of safe drinking water to "problem villages." It set the foundation for all subsequent rural water initiatives. **Analysis of Incorrect Options:** * **B & D. Rajiv Gandhi National Drinking Water Mission / Technology Mission:** In 1986, the "National Drinking Water Mission" (also known as the **Technology Mission**) was launched to improve the quality of water and provide low-cost technological solutions. It was renamed the Rajiv Gandhi National Drinking Water Mission (RGNDWM) in **1991**. These were subsequent evolutions of the ARWSP, not the first. * **C. Swajaldhara:** Launched in **2002**, this was a community-led participatory program where the local community contributed to the capital cost and took over the operation and maintenance of water supply schemes. **High-Yield Clinical Pearls for NEET-PG:** * **Safe Water Definition:** Water that is free from pathogenic agents, harmful chemical substances, pleasant to taste, and usable for domestic purposes. * **Daily Requirement:** For a community, a daily supply of **150–200 liters per capita** is considered adequate for living. * **Current Status:** The RGNDWM has now been subsumed under the **Jal Jeevan Mission (2019)**, which aims to provide Functional Household Tap Connections (FHTC) to every rural household by 2024 (**"Har Ghar Jal"**). * **Standard:** The WHO standard for drinking water turbidity is ideally <1 NTU.

Question 276: Which method of waste disposal is beneficial for soil building?

A. Incineration
B. Controlled tipping
C. Composting (Correct Answer)
D. None of the above

Explanation: **Explanation:** **Composting** is the correct answer because it is a biological process where organic waste is decomposed by microorganisms (bacteria and fungi) under controlled aerobic conditions. The end product, **humus**, is a rich organic fertilizer that improves soil structure, enhances water-holding capacity, and restores essential nutrients (Nitrogen, Phosphorus, Potassium). This process directly contributes to **soil building** by converting waste into a valuable soil conditioner. **Analysis of Incorrect Options:** * **Incineration:** This is a high-temperature dry oxidation process that reduces waste volume by 90%. While excellent for hazardous and infectious medical waste, it destroys organic matter and produces ash, which does not contribute to soil building. * **Controlled Tipping (Sanitary Landfill):** This is a method of disposing of refuse on land without creating nuisances or hazards to public health. While the land may eventually be used for parks or parking lots after 20 years, the primary goal is waste containment and volume reduction, not the active enhancement of soil quality. **High-Yield NEET-PG Pearls:** * **Composting Methods:** The **Bangalore method** (anaerobic) is widely used in India, while the **Indore method** (aerobic) is faster but requires frequent turning. * **Incineration:** The method of choice for **Yellow Bag** waste (anatomical waste, soiled linen). It is contraindicated for PVC, lead, and pressurized containers due to toxic emissions (dioxins/furans). * **Refuse Characteristics:** For composting to be effective, the waste must have an optimal Carbon-to-Nitrogen (C:N) ratio (ideally 20:1 to 30:1).

Question 277: Which of the following is NOT a synthetic pyrethroid insecticide?

A. Propoxur (Correct Answer)
B. Permethrin
C. Cypermethrin
D. Etofenoprox

Explanation: **Explanation:** The correct answer is **Propoxur** because it belongs to the **Carbamate** class of insecticides, not synthetic pyrethroids. 1. **Why Propoxur is the correct answer:** Propoxur is a non-systemic insecticide that acts by inhibiting the enzyme acetylcholinesterase. Unlike pyrethroids, which target sodium channels, carbamates like Propoxur (and Carbaryl) cause reversible inhibition of cholinesterase. It is commonly used in household pest control for ants and cockroaches. 2. **Why the other options are incorrect:** * **Permethrin:** A classic first-generation synthetic pyrethroid. It is widely used in public health for treating mosquito nets (LLINs) and clinically for treating scabies and head lice. * **Cypermethrin:** A potent, fast-acting synthetic pyrethroid used extensively in agriculture and domestic pest control. * **Etofenoprox:** An "ether" derivative of pyrethroids. Unlike most pyrethroids, it lacks a central ester bond, making it unique in structure but still classified functionally within the pyrethroid group. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Synthetic pyrethroids work by prolonging the opening of **voltage-gated sodium channels** in the nerve cells of insects, leading to paralysis (the "knockdown" effect). * **Classification:** * **Type I (No alpha-cyano group):** Permethrin, Allethrin. * **Type II (With alpha-cyano group):** Cypermethrin, Deltamethrin (more potent). * **Safety:** Pyrethroids are generally preferred in public health because they have low mammalian toxicity and are poorly absorbed through the skin. * **Antidote:** There is no specific antidote for pyrethroid poisoning (treatment is symptomatic), whereas **Atropine** is used for Carbamate (Propoxur) poisoning.

Question 278: Which of the following instruments is used to measure humidity?

A. Kata thermometer
B. Globe thermometer
C. Sling psychrometer (Correct Answer)
D. Anemometer

Explanation: **Explanation:** The correct answer is **C. Sling psychrometer**. Humidity refers to the amount of moisture present in the air. A psychrometer is a type of hygrometer used to measure relative humidity. It consists of two thermometers: a **dry-bulb** (measuring actual air temperature) and a **wet-bulb** (wrapped in a wet wick). When the instrument is whirled (slung) in the air, evaporation from the wet bulb causes its temperature to drop. The difference between the two temperatures (wet-bulb depression) is used to calculate relative humidity via psychrometric charts. **Analysis of Incorrect Options:** * **A. Kata Thermometer:** This measures the **cooling power of air** and is primarily used to assess low air velocities (air movement). * **B. Globe Thermometer:** This measures **radiant heat** (mean radiant temperature). It consists of a thermometer placed inside a hollow copper sphere painted matte black. * **D. Anemometer:** This is used to measure **wind speed** or air velocity. A common variant is the Vane Anemometer. **High-Yield Clinical Pearls for NEET-PG:** * **Comfort Zone:** For Indians, the comfortable indoor temperature is 25°C to 30°C with a relative humidity of 30% to 60%. * **Corrected Effective Temperature (CET):** This is the best index of thermal comfort as it accounts for air temperature, humidity, air velocity, and radiant heat. * **Wet Bulb Globe Index (WBGT):** The most widely used heat stress index in occupational health. * **Hygrometer:** A general term for any instrument measuring humidity; the sling psychrometer is the most accurate field version.

Question 279: Per capita space for students in a classroom should not be less than what minimum area in square feet?

A. 5
B. 10 (Correct Answer)
C. 20
D. 50

Explanation: **Explanation:** The correct answer is **10 square feet**. This standard is established under the guidelines for school health services to ensure adequate ventilation and prevent overcrowding, which is a primary risk factor for the transmission of respiratory infections (like tuberculosis, influenza, and meningococcal meningitis) among students. * **Why 10 sq. ft. is correct:** According to the recommendations for school environments in India, the minimum floor space required per student in a classroom is **10 sq. ft.** This area allows for sufficient physical distancing and ensures that the air volume per child is adequate to maintain indoor air quality. * **Why A (5 sq. ft.) is incorrect:** This area is insufficient and would lead to extreme overcrowding, facilitating the rapid spread of droplet-borne infections. * **Why C (20 sq. ft.) is incorrect:** While 20 sq. ft. would provide excellent spacing, it is not the *minimum* legal or recommended standard for general classrooms. However, larger areas may be required for specialized laboratories. * **Why D (50 sq. ft.) is incorrect:** This value is far beyond the standard requirement for a classroom setting and is more characteristic of specialized medical wards or isolation units. **High-Yield Clinical Pearls for NEET-PG:** * **Window Area:** Should be at least **1/5th** of the total floor area to ensure adequate natural light and ventilation. * **Combined Desk & Bench:** The maximum number of students per bench is **two**. * **Distance from Blackboard:** The front row of students should be at least **8 feet** away from the chalkboard. * **Sanitation:** One urinal is required for every **60 students**, and one latrine for every **100 students**.

Question 280: Which of the following is NOT a responsibility of an Anganwadi worker?

A. Immunization of children
B. Non-formal preschool education
C. Sanitation (Correct Answer)
D. Health education

Explanation: The **Anganwadi Worker (AWW)** is the community-based voluntary frontline worker under the **Integrated Child Development Services (ICDS)** scheme. ### **Explanation of the Correct Option** **C. Sanitation:** While the AWW promotes hygiene awareness, the actual responsibility for environmental sanitation (such as waste management, drainage, and construction of latrines) lies with the **Village Health Sanitation and Nutrition Committee (VHSNC)** and the **Panchayati Raj Institutions**. The AWW acts as a facilitator but is not the primary provider or executor of sanitation services. ### **Analysis of Incorrect Options** * **A. Immunization of children:** The AWW assists the ANM (Auxiliary Nurse Midwife) by mobilizing children and pregnant women, maintaining records, and organizing the site for immunization sessions (e.g., Village Health and Nutrition Days). * **B. Non-formal preschool education:** This is a core function of the AWW for children aged 3–6 years to ensure psychological and social development before primary school. * **C. Health education:** AWWs provide health and nutrition education to mothers and adolescent girls regarding breastfeeding, complementary feeding, and family planning. ### **High-Yield Facts for NEET-PG** * **ICDS Beneficiaries:** Children (<6 years), pregnant and lactating mothers, and adolescent girls (11–18 years). * **Population Norms:** One Anganwadi center per **400–800** population in rural/urban areas and **300–800** in tribal areas. * **Key Services:** Supplementary nutrition, Pre-school non-formal education, Nutrition & health education, Immunization, Health check-up, and Referral services. * **The "Golden Rule":** AWW provides the first four services directly, while the latter two (Immunization and Health check-ups) are provided by the ANM/MO with the AWW’s assistance.

Practice by Chapter

Water Quality and Health

Practice Questions

Air Pollution and Health Effects

Practice Questions

Solid Waste Management

Practice Questions

Hazardous Waste Management

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Housing and Health

Practice Questions

Noise Pollution

Practice Questions

Radiation Health Effects

Practice Questions

Climate Change and Health

Practice Questions

Environmental Impact Assessment

Practice Questions

Disaster Management and Preparedness

Practice Questions

Vector Control

Practice Questions

Environmental Legislation

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