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Question
The following table contains the number of dengue cases reported in a hospital over one year: January 10, February 12, March 15, April 18, May 22, June 40, July 65, August 65, September 65, October 30, November 30, December 20.
Make a bar graph of the number of cases (Y-axis) against the month (X-axis). Critically analyse and answer:
(i) In which three months were the dengue cases highest?
(ii) In which month(s) were the cases lowest?
(iii) What natural or environmental factors during the peak months might contribute to the increase?
(iv) Suggest a few preventive steps the community or government can take before the peak season.
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Answer
Why do dengue cases peak from July to September?
The monsoon arrives
Rain collects and stands in the open
↓
Still water gathers
In pots, tyres, coolers and puddles
↓
Mosquitos breed in it
The dengue virus is carried by mosquitos
↓
Cases climb to their peak in July, August and September, and fall by December
Cases peak in July–September (monsoon) and are lowest in January; prevention means clearing still water early.
Explanation
- (i) The highest cases are in July, August, and September (65 each).
- (ii) The lowest is in January (10 cases).
- (iii) The monsoon brings rain and still water where mosquitoes breed, raising dengue cases.
- (iv) Clear stagnant water, use nets and repellents, spray for mosquitoes, and run awareness drives before the season.
Peak in the monsoon months (Jul–Sep), lowest in January; clear still water to prevent dengue.
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