FMGE 2025 - Community Medicine Practice Questions

Q: Which of the following substances, at the given concentration, makes water unsuitable for human consumption according to safety standards?

Cadmium – 0.3 mg/L. ***Cadmium – 0.3 mg/L*** - The maximum permissible limit for **Cadmium** in drinking water is extremely low, typically around **0.003 mg/L** (WHO standard), due to its high toxicity. - A concentration of 0.3 mg/L is 100 times the safe limit and poses severe health risks, particularly **kidney damage**. *Fluoride – 0.8 mg/L* - The optimal acceptable range for **Fluoride** is generally between **0.6 and 1.5 mg/L**, a concentration that helps prevent dental caries. - A concentration of 0.8 mg/L is well within the acceptable limit and is often considered optimal for public health. *Chloride – 200 mg/L* - The acceptable limit for **Chloride** is usually **250 mg/L** (or up to 1000 mg/L as the maximum permissible limit), with higher levels primarily affecting taste and causing corrosion. - 200 mg/L is below the acceptable range and does not render the water unsuitable for drinking. *Calcium – 7 mg/L* - **Calcium** is an essential mineral, and its typical acceptable limit for drinking water is much higher, often around **75 mg/L** (or related to overall water hardness). - This concentration is extremely low and poses no health risk; it is perfectly safe for consumption.

Q: Which mosquito species is recognized as the principal secondary vector for Zika virus transmission globally?

Aedes albopictus. ***Aedes albopictus*** - This mosquito, commonly known as the **Asian tiger mosquito**, is recognized as the **principal secondary vector** for Zika virus transmission globally. - It is a competent vector capable of transmitting **Zika**, **Dengue**, and **Chikungunya** viruses across multiple continents including Asia, Europe, Africa, and the Americas. - While *Aedes aegypti* remains the primary vector, *Aedes albopictus* plays a significant role in Zika transmission, particularly in temperate regions where *Ae. aegypti* is less prevalent. - Its adaptability to diverse climates and ability to breed in natural and artificial water containers make it epidemiologically important. *Aedes polynesiensis* - This species is primarily known as a vector for **lymphatic filariasis** (*Wuchereria bancrofti*) in Pacific islands. - While it was involved in Zika virus transmission during the **French Polynesia outbreak (2013-2014)**, it is geographically restricted and not considered a principal vector for global Zika transmission. - Its role is limited to specific Pacific island populations. *Aedes australis* - This species is endemic to Australia and transmits **Ross River virus** and other Australian arboviruses. - It is **not** a recognized vector for Zika virus transmission. - Its geographical distribution and host preferences exclude it from the Zika transmission cycle. *Aedes mitchellae* - This species is not documented in major public health literature as a vector for Zika virus. - It belongs to a mosquito species complex with no established role in arboviral transmission to humans. - Epidemiologically insignificant for Zika virus transmission.

Q: A chronic smoker who worked in a cement factory for the past 20 years developed mesothelioma. This association is most likely due to?

Asbestosis. ***Asbestosis*** - **Mesothelioma**, a malignant tumor of the pleura, is almost exclusively caused by occupational exposure to **asbestos fibers**. Cement factory work is a well-known source of this exposure. - The combination of smoking and asbestos exposure has a synergistic effect, massively increasing the risk for **bronchogenic carcinoma**, but asbestos alone is the primary risk factor for **mesothelioma**. *Bagassosis* - This is a type of **hypersensitivity pneumonitis** caused by inhaling dust from moldy **sugarcane** residue (bagasse). - It is an allergic inflammatory condition and is not associated with the development of **mesothelioma**. *Silicosis* - Caused by the inhalation of **silica dust**, common in mining and sandblasting, it classically affects the **upper lobes** of the lungs. - While it increases the risk for **tuberculosis** and lung cancer, it is not a recognized cause of **mesothelioma**. *Coal worker pneumoconiosis* - Also known as **"black lung disease"**, this condition is caused by the chronic inhalation of **coal dust**. - It is characterized by **coal macules** in the lungs and is not associated with an increased risk of **mesothelioma**.

Q: On January 1, 2024, an area with a population of 10,000 had 100 TB cases. During the year, 30 patients were cured and 10 died. Twenty new TB cases were reported, and 5 of them were cured before December 31, 2024. What is the incidence and prevalence of TB cases?

2 and 1.2. ***2 and 1.2*** - **Incidence** represents the rate of new cases occurring during the year. With 20 new TB cases in a population of 10,000, the incidence rate is: $$\frac{20}{10,000} \times 1000 = 2 \text{ per 1000 population}$$ - **Prevalence** in this context appears to refer to the cumulative case load or period prevalence. The total number of cases that existed at any point during the year = Initial cases + New cases = 100 + 20 = 120 cases. Expressed as a percentage: $$\frac{120}{10,000} \times 100 = 1.2\%$$ - This interpretation gives us **incidence of 2 per 1000** and **prevalence of 1.2%** *1.2 and 10* - Incidence of 1.2 would suggest only 12 new cases per 10,000 population, which is incorrect. The actual number of new cases is 20, giving an incidence of 2 per 1000 - The value 10 represents the number of deaths, not the prevalence rate *1.2 and 12* - Incidence of 1.2 is incorrect as explained above - While 12 per 1000 (or 1.2%) could represent prevalence, pairing it with the wrong incidence value makes this option incorrect *2 and 10* - Incidence of 2 per 1000 is correct - However, 10 represents the number of deaths, not the prevalence. The prevalence value should be 1.2% (representing 120 total cases as a percentage of the population) **Key Epidemiological Concepts:** - **Incidence** = Number of NEW cases during a time period / Population at risk - **Prevalence** = Total number of existing cases / Total population - In this question, the prevalence of 1.2% represents the cumulative case burden (100 initial + 20 new = 120 cases) expressed as a percentage of the population (120/10,000 × 100 = 1.2%)

Q: In which of the following should a cotton swab with pus be discarded?

Yellow non-chlorination bag. ***Yellow non-chlorination bag*** - Cotton swabs soiled with pus are classified as **Soiled Waste** (infectious waste) which must be collected in the designated **yellow bag**.- To prepare this waste for final disposal via **incineration** or deep burial, it should not undergo pre-treatment like chlorination; hence, it goes into a non-chlorination yellow bag.*Yellow chlorination bag*- Chemical disinfection, such as **chlorination**, is primarily performed on liquid microbiological waste or highly contaminated liquid waste before discharge, not typically inside the collection bag for solid soiled cotton waste.- Soiled waste collected in the yellow bag is destined for **high-temperature treatment** (incineration), making immediate chlorination within the bag unnecessary and potentially hazardous.*Red chlorination bag*- The **red bag** is designated for **contaminated recyclable plastic waste** (like IV bottles, catheters, syringes without needles), which is processed via autoclaving/microwave disinfection.- Cotton swabs are non-plastic, **non-recyclable soiled waste** and therefore do not belong in the red category.*Red non-chlorination bag*- The **red bag** is strictly reserved for contaminated **plastic and rubber items** that require disinfection before recycling.- Since the cotton swab is **soiled non-plastic waste**, it must be segregated into the yellow category, regardless of whether chlorination is used or not (which it is not for this item).

Q: An elderly man presents with leg deformities and skeletal abnormalities. On examination, he is using crutches and has visible bowing of the legs. It is also noted that several other villagers exhibit similar symptoms. Considering the cluster of cases in the same geographic area, which of the following is the most appropriate next step in the investigation?

Collect and analyze water samples for fluoride content. ***Collect and analyze water samples for fluoride content*** - The presentation of a cluster of cases with **skeletal deformities** (bowing of the legs) in a single geographic area strongly suggests an endemic condition related to an **environmental exposure**, such as a contaminated water source. - The clinical picture is highly consistent with **skeletal fluorosis**, and the accompanying image showing mottled enamel is a classic sign of **dental fluorosis**, both caused by chronic high intake of fluoride. *Check serum vitamin D levels* - Vitamin D deficiency causes **osteomalacia** in adults, which can lead to bone deformities, but it does not cause the specific **dental fluorosis** seen in the image. - While a community-wide nutritional deficiency is possible, the combination of skeletal and dental findings makes an environmental toxin a more specific and likely cause to investigate first. *Measure serum calcium levels* - Serum calcium levels are typically **normal** in patients with skeletal fluorosis, so this test would have low diagnostic yield for the suspected condition. - While metabolic bone diseases can present with abnormal calcium, they do not explain the endemic nature of the presentation or the characteristic dental findings. *Perform parathyroid hormone (PTH) assay* - **Hyperparathyroidism** is an endocrine disorder that is unlikely to affect multiple individuals in the same village simultaneously. - The clinical and radiological features of hyperparathyroidism, such as **osteitis fibrosa cystica**, differ from those of skeletal fluorosis, and it is not associated with dental fluorosis.

Q: A patient presents with increased consumption of Bajra (pearl millet) roti and now complains of drowsiness and giddiness. What is the most likely diagnosis?

Ergotism. ***Ergotism*** - This condition results from ingesting grains, such as **pearl millet (Bajra)**, contaminated by the fungus *Claviceps fusiformis*. - The neurotoxic effects of **ergot alkaloids** cause the central nervous system (CNS) symptoms of the convulsive form, including **drowsiness** and **giddiness**. *Epidemic Dropsy* - This toxicity is caused by ingesting edible oils (typically mustard oil) contaminated with **argemone oil**. - The cardinal features are non-pitting **edema** (dropsy), skin pigmentation, and rarely, secondary glaucoma, not primarily CNS giddiness. *Botulism* - This illness is caused by the potent neurotoxin produced by *Clostridium botulinum*, usually found in improperly canned or preserved food. - The defining clinical presentation is a classic descending, symmetric **flaccid paralysis** often starting with cranial nerve symptoms (**diplopia, dysphagia**). *Fusarium Toxicity* - This involves various mycotoxins (e.g., **fumonisins, T-2 toxin**) contaminating cereals, most commonly maize. - Clinical syndromes include severe immunosuppression (Alimentary Toxic Aleukia) or liver/kidney damage, not the primary presentation of acute drowsiness and giddiness.

Q: In a group, the mean blood glucose level is 105 mg/dL with a standard deviation of 10 mg/dL. Assuming a normal distribution, what is the expected range of blood glucose values for approximately 95% of the population?

85 – 125 mg/dL. ***85 – 125 mg/dL*** - This range is calculated using the **Empirical Rule** ($\text{Mean} \pm 2 \text{ SD}$), which states that approximately 95% of observations in a **normal distribution** fall within two standard deviations of the mean. - Calculation: $105 \text{ mg/dL} \pm (2 \times 10 \text{ mg/dL}) = 105 \pm 20 \text{ mg/dL}$, resulting in the range **85 – 125 mg/dL**. *101 – 110 mg/dL* - This range is too narrow, only covering values $5 \text{ mg/dL}$ above and below the mean, and does not represent the required **95%** coverage for a 10 mg/dL standard deviation. - Using this small range indicates an incorrect application of the **standard deviation** multiplier necessary for determining large confidence intervals. *90 – 125 mg/dL* - While the upper limit ($125 \text{ mg/dL}$) is correct ($\text{Mean} + 2 \text{ SD}$), the lower limit ($90 \text{ mg/dL}$) is incorrect, as it must be symmetrical around the mean in a **normal distribution**. - This asymmetrical range does not accurately represent the **95% confidence interval** defined by $\text{Mean} \pm 2 \text{ SD}$. *95 – 115 mg/dL* - This range is calculated using $\text{Mean} \pm 1 \text{ SD}$ ($105 \pm 10 \text{ mg/dL}$), which only includes approximately **68%** of the data according to the **Empirical Rule**, not 95%. - To capture **95%** of the population data, clinicians and students must use **two standard deviations** from the mean.

Q: In a family with three siblings, the eldest sibling moves out of the household, and a new (third) child is born. What is this change in the family structure called?

Complete extension. ***Complete extension*** - This stage of the family life cycle begins with the birth of the **last child**, representing the point at which the family has reached its maximum size. - Although the eldest sibling has moved out (a contraction event), the birth of the new child marks the completion of the family's growth phase. *Formation* - The formation stage starts with **marriage** and lasts until the birth of the **first child**. - This family already has multiple children, indicating they are well beyond the initial formation stage. *Contraction* - The contraction stage begins when the **first child leaves home** and ends when the last child leaves, leading to the "empty nest" stage. - While a child leaving home is an event of contraction, the overall stage is defined by the final birth, which is complete extension. *Extension* - The extension stage is a broader phase that starts with the birth of the **first child** and continues as more children are born. - "Complete extension" is the more specific and accurate term for the point when the **last child** is born, finalizing the family's size.

Question 1

Which of the following substances, at the given concentration, makes water unsuitable for human consumption according to safety standards?

Accepted Answer

Cadmium – 0.3 mg/L

Answer

Calcium – 7 mg/L

Answer

Chloride – 200 mg/L

Answer

Fluoride – 0.8 mg/L

Question 2

Which mosquito species is recognized as the principal secondary vector for Zika virus transmission globally?

Accepted Answer

Aedes albopictus

Answer

Aedes polynesiensis

Answer

Aedes australis

Answer

Aedes mitchellae

Question 3

A chronic smoker who worked in a cement factory for the past 20 years developed mesothelioma. This association is most likely due to?

Accepted Answer

Asbestosis

Answer

Silicosis

Answer

Coal worker pneumoconiosis

Answer

Bagassosis

Question 4

On January 1, 2024, an area with a population of 10,000 had 100 TB cases. During the year, 30 patients were cured and 10 died. Twenty new TB cases were reported, and 5 of them were cured before December 31, 2024. What is the incidence and prevalence of TB cases?

Accepted Answer

2 and 1.2

Answer

1.2 and 12

Answer

2 and 10

Answer

1.2 and 10

Question 5

In which of the following should a cotton swab with pus be discarded?

Accepted Answer

Yellow non-chlorination bag

Answer

Yellow chlorination bag

Answer

Red non-chlorination bag

Answer

Red chlorination bag

Question 6

An elderly man presents with leg deformities and skeletal abnormalities. On examination, he is using crutches and has visible bowing of the legs. It is also noted that several other villagers exhibit similar symptoms. Considering the cluster of cases in the same geographic area, which of the following is the most appropriate next step in the investigation?

Accepted Answer

Collect and analyze water samples for fluoride content

Answer

Perform parathyroid hormone (PTH) assay

Answer

Check serum vitamin D levels

Answer

Measure serum calcium levels

Question 7

A patient presents with increased consumption of Bajra (pearl millet) roti and now complains of drowsiness and giddiness. What is the most likely diagnosis?

Accepted Answer

Ergotism

Answer

Fusarium Toxicity

Answer

Botulism

Answer

Epidemic Dropsy

Question 8

Out of the MR & Pentavalent vaccine, which can be reused, and which one should be discarded when the vial is opened according to the open vial policy?

Accepted Answer

Discard MR, reuse Pentavalent

Answer

Reuse both MR and Pentavalent

Answer

Discard both MR and Pentavalent

Answer

Discard Pentavalent, reuse MR

Question 9

In a group, the mean blood glucose level is 105 mg/dL with a standard deviation of 10 mg/dL. Assuming a normal distribution, what is the expected range of blood glucose values for approximately 95% of the population?

Accepted Answer

85 – 125 mg/dL

Answer

101 – 110 mg/dL

Answer

95 – 115 mg/dL

Answer

90 – 125 mg/dL

Question 10

In a family with three siblings, the eldest sibling moves out of the household, and a new (third) child is born. What is this change in the family structure called?

Accepted Answer

Complete extension

Answer

Contraction

Answer

Formation

Answer

Extension

FMGE 2025 — Community Medicine