An increase in dengue cases during the end of the rainy season is an example of which type of epidemic?

AIIMS M.Sc. Nsg Entrance exam-2026

Community Health Nursing

Medium

Appeared in: AIIMS M.Sc. Nsg Entrance exam-2026

Explanation

The increase in dengue cases at the end of the rainy season is a predictable, recurring pattern tied to a specific time of year.
In epidemiology, such a pattern is defined as a cyclical or seasonal trend.
This trend is driven by environmental factors—the rainy season creates breeding sites for the Aedes mosquito, the vector for dengue virus.
While the term 'secular' in the option refers to long-term trends (decades), the inclusion of '(cyclical)' correctly identifies the seasonal nature of the outbreak, making it the best available answer.

Option A: A propagated epidemic involves the spread of a disease from person to person. While dengue can be transmitted between people via a mosquito, the large-scale outbreak pattern described is dictated by the vector's seasonal life cycle, not direct human-to-human transmission.
Option B: 'Time interval epidemic' is not a standard classification used in epidemiology to describe disease trends. The established terms are secular, cyclical/seasonal, and short-term fluctuations (epidemics).
Option C: A point source epidemic results from a group of people being exposed to a single, common infectious source (like contaminated food or water) at one specific point in time. This causes a rapid, explosive increase in cases, which is different from the recurring, seasonal pattern of dengue.

Visual 1: Line Graph - A graph showing the number of dengue cases on the y-axis and months of the year on the x-axis. The graph would display sharp peaks in the months following the rainy season, demonstrating the cyclical/seasonal trend.
Visual 2: Infographic - An infographic illustrating the life cycle of the Aedes mosquito, highlighting how stagnant water (from rain, stored water) is essential for its eggs to hatch and mature, thus linking the rainy season to an increased vector population.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Epidemiological time trends and classification of disease patterns as background academic context rather than a clinical decision trigger.
Understanding that dengue follows a seasonal trend is critical for public health. It allows health authorities to anticipate outbreaks, prepare hospitals, and launch timely public awareness and vector-control campaigns before and during the rainy season.
Nurses are at the forefront of this effort, educating patients and communities on how to eliminate mosquito breeding sites (e.g., by emptying stagnant water from containers) and how to recognize the early signs of dengue.
What if? If a large number of dengue cases were reported in the dry season in a localized area, it would prompt an investigation for a non-seasonal cause, such as a new, persistent breeding site (e.g., a construction site with poor water management), rather than assuming the usual seasonal trend.

How to Approach the Question

First, identify the key elements in the question: 'increase in dengue cases' and 'end of the rainy season'.
Recognize that the question is asking you to classify a disease pattern based on its timing.
The phrase 'rainy season' is a strong clue that the pattern is seasonal or cyclical, meaning it repeats at a predictable time each year.
Next, evaluate the given options based on standard epidemiological definitions.
Eliminate 'Point source epidemic' (single event, like food poisoning) and 'Propagated epidemic' (person-to-person spread, like measles).
Analyze the remaining option, 'Secular (cyclical) trend'. Acknowledge that 'secular' refers to long-term trends, but 'cyclical' perfectly matches the seasonal pattern described. Since the other options are clearly incorrect, this is the best possible answer.

Concept Tested & Keywords

Concept Tested: Epidemiological time trends and classification of disease patterns.
Stem keywords: dengue cases, rainy season, epidemic
Lead-in keywords: which type
Clinical cues: The link between the disease (dengue) and a specific time of year (end of rainy season) is the key clinical cue pointing towards a seasonal pattern.

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