Environmental Health Practice Questions

Q: All the following are fishes used in biological control of vectors except?

Coelomomyces. ### Explanation The question tests your knowledge of **Biological Control Methods** used in Integrated Vector Management (IVM). Biological control involves using living organisms to reduce the population of disease-carrying vectors, primarily mosquitoes. **Why Coelomomyces is the correct answer:** **Coelomomyces** is not a fish; it is a genus of **entomopathogenic fungi**. It acts as an obligate parasite that infects and kills mosquito larvae. While it is a biological control agent, it belongs to the category of fungi/microbial control, not larvivorous fish. **Analysis of Incorrect Options (Larvivorous Fish):** Larvivorous fish are used to control mosquito breeding in permanent water bodies (wells, tanks, ponds) by feeding on larvae. * **Gambusia affinis (Mosquito fish):** The most widely used fish globally. A single Gambusia can consume about 100–300 larvae per day. It is hardy and can survive in varying water conditions. * **Poecilia reticulata (Guppy):** Another highly effective larvivorous fish. It is particularly useful because it can tolerate high levels of organic pollution (e.g., in drains and sewage-polluted water). * **Aplocheilus (Panchax):** A genus of small, surface-feeding fish native to India. They are efficient predators of mosquito larvae in freshwater habitats. **High-Yield NEET-PG Pearls:** * **Gambusia vs. Poecilia:** Use Gambusia for clean water and Poecilia for polluted water. * **Other Biological Agents:** *Bacillus thuringiensis israelensis* (BTI) and *Bacillus sphaericus* are bacteria used as biolarvicides. * **Larvivorous Fish Strategy:** This is a component of the **National Center for Vector Borne Diseases Control (NCVBDC)** strategy for malaria and dengue control. * **Criteria for Larvivorous Fish:** They must be small, hardy, drought-resistant, and prefer larvae over other food sources.

Q: Which of the following is NOT an objective of the Mental Health Act, 1987?

Human rights for mentally ill individuals. **Explanation:** The **Mental Health Act (MHA), 1987** was primarily an administrative and regulatory framework focused on the establishment of mental health authorities, regulation of psychiatric hospitals, and procedures for the admission and detention of mentally ill persons. **Why Option D is the Correct Answer:** While the MHA 1987 touched upon the protection of rights, it was heavily criticized for being **custodial** rather than rights-based. The explicit focus on **Human Rights for mentally ill individuals** is the hallmark of the **Mental Healthcare Act (MHCA), 2017**, which replaced the 1987 Act. The 2017 Act introduced the "Right to Access Healthcare" and "Advance Directives," shifting the focus from legal detention to patient autonomy and human rights. **Analysis of Incorrect Options (Objectives of MHA 1987):** * **Option A & B:** The 1987 Act aimed to decentralize mental health services, encouraging **community participation** and the **integration of mental health knowledge into general healthcare** to reduce stigma and increase accessibility. * **Option C:** Providing **minimal mental health care for all** (especially the vulnerable) was a core objective aligned with the National Mental Health Programme (NMHP) 1982, which the MHA 1987 sought to implement legally. **High-Yield Clinical Pearls for NEET-PG:** * **MHA 1987:** Focused on "Mentally ill persons" and "Psychiatric hospitals." * **MHCA 2017:** Focused on "Persons with mental illness" (PWMI) and "Mental health establishments." * **Decriminalization of Suicide:** Under Section 115 of the MHCA 2017, a person attempting suicide is presumed to be under severe stress and shall not be punished. * **Prohibition of ECT:** Direct ECT (without anesthesia) is prohibited under the 2017 Act.

Q: What is the confirmatory test for coliform count?

Eijkman test. ### Explanation **1. Why the Correct Answer is Right:** The **Eijkman test** (also known as the Differential Coliform Test) is the confirmatory test used to identify fecal coliforms, specifically *Escherichia coli*, in water samples. While the presumptive coliform count (Multiple Tube Fermentation) suggests the presence of the coliform group, the Eijkman test confirms fecal origin. It involves incubating the sample in MacConkey broth at a specific temperature of **44°C**. The production of **gas** at this temperature is diagnostic for *E. coli*, distinguishing it from non-fecal coliforms which cannot produce gas at such high temperatures. **2. Why the Other Options are Incorrect:** * **Casoni’s test:** This is an immediate hypersensitivity skin test used for the diagnosis of **Hydatid disease** (*Echinococcus granulosus*). It has largely been replaced by serological tests and imaging. * **Nitrate test:** This test detects the ability of bacteria to reduce nitrate to nitrite. It is commonly used to identify members of the *Enterobacteriaceae* family and is a component of the **Urinalysis** dipstick to screen for UTIs. * **Urease test:** This biochemical test identifies organisms that produce the enzyme urease (e.g., *Proteus*, *Klebsiella*, and *H. pylori*), which hydrolyzes urea into ammonia and CO₂. **3. High-Yield Clinical Pearls for NEET-PG:** * **Indicator Organism:** *E. coli* is the best indicator of **recent** fecal contamination of water. * **Presumptive Coliform Count:** Performed using the Multiple Tube Method; results are expressed as the **Most Probable Number (MPN)** per 100 ml. * **WHO Standards:** For drinking water, *E. coli* or thermotolerant coliform bacteria must **not be detectable in any 100 ml sample**. * **Coliform Characteristics:** Gram-negative, non-spore-forming bacilli that ferment lactose with the production of acid and gas within 48 hours at 35°C.

Q: Hard tick causes which of the following diseases?

Tick typhus. **Explanation:** Hard ticks (family **Ixodidae**) are significant vectors in community medicine, responsible for transmitting several rickettsial and viral infections. **Tick typhus** (specifically Indian Tick Typhus caused by *Rickettsia conorii*) is transmitted to humans through the bite of an infected hard tick. The tick acts as both a vector and a reservoir, maintaining the pathogen through transovarial and transstadial transmission. **Analysis of Options:** * **A & B (Oriental sore & Kala-azar):** Both are forms of Leishmaniasis. They are transmitted by the **Sandfly** (*Phlebotomus argentipes*), not ticks. Oriental sore is the cutaneous form, while Kala-azar is the visceral form. * **C (Tick typhus):** This is the **correct** answer. Hard ticks (e.g., *Rhipicephalus sanguineus*) are the primary vectors. * **D (Q fever):** While ticks can maintain the cycle of *Coxiella burnetii* in wild animals, the primary mode of transmission to humans is via **inhalation of infected dust/aerosols** from livestock (cattle, sheep, goats), not typically through a tick bite. **High-Yield Clinical Pearls for NEET-PG:** * **Diseases transmitted by Hard Ticks:** Tick typhus, Kyasanur Forest Disease (KFD), Tularemia, Tick paralysis, Babesiosis, and Human Monocytic Ehrlichiosis. * **Diseases transmitted by Soft Ticks:** Relapsing fever and Q fever (rarely). * **Distinguishing feature:** Hard ticks have a dorsal shield (**scutum**), which is absent in soft ticks. * **KFD (Kyasanur Forest Disease):** A high-yield viral hemorrhagic fever in India transmitted by the hard tick *Haemaphysalis spinigera*.

Q: What is the term for wastewater originating from a kitchen?

Sullage. **Explanation:** In Environmental Health, wastewater is classified based on its source and content. The correct answer is **Sullage** because it specifically refers to wastewater that does not contain human excreta. 1. **Why Sullage is Correct:** Sullage is the wastewater originating from household activities such as **kitchens, bathrooms, and laundries**. It contains food particles, grease, soap, and dirt but lacks significant organic matter from human waste. In the context of rural sanitation, sullage is typically managed through soakage pits. 2. **Analysis of Incorrect Options:** * **Refuse (A):** This is a broad term for all solid waste produced by a community. It includes both compostable and non-compostable materials but excludes human excreta. * **Garbage (B):** This is a sub-type of refuse. It specifically refers to **putrescible (organic/decomposable) solid waste**, such as leftover food, vegetable peels, and fruit waste. * **Sewage (D):** This is wastewater that **contains human excreta** (night soil). It is a mixture of water and organic/inorganic solids in solution or suspension, originating from toilets, urinals, and industrial liquid waste. **High-Yield NEET-PG Pearls:** * **Sewerage:** The infrastructure (pipes/pumps) used to transport sewage. * **Night Soil:** A term specifically used for human excreta. * **BOD (Biochemical Oxygen Demand):** The most important indicator of the organic strength of sewage. * **Sludge:** The solid matter that settles at the bottom of a septic tank or sedimentation tank during sewage treatment.

Q: What is the basic minimum illumination required for satisfactory vision?

15-20 foot candles. ### Explanation **1. Understanding the Correct Answer (Option B: 15-20 foot candles)** In Community Medicine and Environmental Health, illumination is measured to ensure visual comfort and prevent eye strain. According to standard public health guidelines (often cited from Park’s Textbook of Preventive and Social Medicine), the **basic minimum illumination** required for satisfactory vision—allowing for comfortable reading and general work without fatigue—is **15 to 20 foot candles**. This level ensures adequate contrast and detail recognition for the human eye under standard conditions. **2. Analysis of Incorrect Options** * **Option A (10-15 foot candles):** This level is considered insufficient for tasks requiring sustained mental concentration or detailed visual work. It may be adequate for corridors or storage areas but falls below the "satisfactory" threshold for general functional vision. * **Options C & D (20-30 foot candles):** While these levels provide excellent visibility, they exceed the *basic minimum* requirement. These higher intensities are typically recommended for specialized tasks involving fine detail, such as precision engineering, sewing, or surgical procedures, rather than general satisfactory vision. **3. High-Yield Clinical Pearls for NEET-PG** * **Units of Measurement:** * **Luminous Intensity:** Measured in **Candela**. * **Luminous Flux:** Measured in **Lumens**. * **Illumination (Illuminance):** Measured in **Lux** (metric) or **Foot-candles** (imperial). * *Conversion:* **1 Foot-candle ≈ 10.76 Lux.** * **Standards for Schools:** The recommended illumination for classrooms is generally higher, around **15-30 foot candles** (or 150-300 Lux) to prevent myopia and asthenopia (eye strain) in children. * **Factors Affecting Lighting:** Satisfactory lighting depends on five factors: Intensity, Distribution, Absence of Glare, Absence of Sharp Shadows, and Color of light.

Question 1

All the following are fishes used in biological control of vectors except?

Accepted Answer

Coelomomyces

Answer

Gambusia

Answer

Poccilla

Answer

Aplochelius

Question 2

Disinfection of water is not required if the source is from which of the following?

Accepted Answer

Tube well

Answer

Step well

Answer

Draw well

Answer

River

Question 3

Which of the following is NOT an objective of the Mental Health Act, 1987?

Accepted Answer

Human rights for mentally ill individuals

Answer

Promote community participation

Answer

Application of mental health knowledge in general healthcare

Answer

Minimal mental health care for all

Question 4

What is a feature of a slow sand filter compared to a rapid sand filter?

Accepted Answer

Requires more time for purification

Answer

Occupies less space

Answer

Requires highly skilled operation

Answer

Results in poor bacterial quality of water

Question 5

What is the confirmatory test for coliform count?

Accepted Answer

Eijkman test

Answer

Casoni's test

Answer

Nitrate test

Answer

Urease test

Question 6

Hard tick causes which of the following diseases?

Accepted Answer

Tick typhus

Answer

Oriental sore

Answer

Kala-azar (Visceral leishmaniasis)

Answer

Q fever

Question 7

If the second cup of Horrock's apparatus shows a blue color after 3 drops of starch-iodine indicator, what dose of bleaching powder is required to disinfect 910 L?

Accepted Answer

8 gm

Answer

30 gm

Answer

4 gm

Answer

15 gm

Question 8

What is the term for wastewater originating from a kitchen?

Accepted Answer

Sullage

Answer

Refuse

Answer

Garbage

Answer

Sewage

Question 9

What is the basic minimum illumination required for satisfactory vision?

Accepted Answer

15-20 foot candles

Answer

10-15 foot candles

Answer

20-25 foot candles

Answer

25-30 foot candles

Question 10

Which of the following health hazards are associated with environmental lead exposure?

Accepted Answer

Lowering of IQ in children, reduced RBC survival and reduced heme biosynthesis, and higher rates of miscarriages, stillbirths, and preterm deliveries

Answer

Lowering of IQ in children, lowering of systolic blood pressure, reduced RBC survival and reduced heme biosynthesis, and higher rates of miscarriages, stillbirths, and preterm deliveries

Answer

Lowering of IQ in children and lowering of systolic blood pressure

Answer

Lowering of IQ in children, lowering of systolic blood pressure, and reduced RBC survival and reduced heme biosynthesis

Environmental Health — MCQs

Environmental Health — MCQs

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