A Treat for Mosquitoes — Class 5 EVS (CBSE)
Based on the NCERT Looking Around Grade 5 textbook. Learn about mosquitoes, the diseases they spread, and how to prevent them.
1. Why this chapter matters
Mosquitoes are small insects, but they cause serious diseases like malaria and dengue. This chapter teaches students about the mosquito life cycle, where they breed, and how they spread diseases. Students learn about the important work of Sir Ronald Ross, who discovered that mosquitoes spread malaria. Most importantly, the chapter teaches prevention — how to protect ourselves and our communities from mosquito-borne diseases.
2. Mosquito life cycle
A mosquito goes through four stages in its life cycle:
| Stage | Where it lives | What it looks like | Time |
|---|---|---|---|
| Egg | In or near water | Tiny black or white eggs, laid in clusters | 2-3 days |
| Larva (wriggler) | In water | Small, worm-like, moves by wriggling | 5-7 days |
| Pupa (tumbler) | In water | Comma-shaped, does not eat, resting stage | 2-3 days |
| Adult | In the air | Fully formed mosquito | Up to 1 month |
The entire life cycle takes about 10-14 days, depending on the temperature. That is why mosquitoes can multiply very quickly.
3. Where mosquitoes breed
Mosquitoes lay eggs in standing water — water that does not flow. Common breeding places:
- Stagnant water in open drains
- Puddles and waterlogged areas
- Water collected in old tyres, buckets, tins, coconut shells
- Coolers and water tanks left uncovered
- Flower pots and plant saucers
- Ponds and ditches
Types of mosquitoes
| Type | Breeding ground | Disease caused |
|---|---|---|
| Anopheles | Clean, fresh water | Malaria |
| Aedes | Clean water in containers | Dengue, Chikungunya |
| Culex | Dirty, stagnant water | Filariasis (elephantiasis) |
4. Diseases caused by mosquitoes
Malaria
- Caused by a parasite called Plasmodium.
- Spread by the female Anopheles mosquito.
- Symptoms: High fever with chills, headache, body pain.
- Prevention: Mosquito nets, repellents, removing stagnant water.
- Sir Ronald Ross discovered the link between mosquitoes and malaria in 1897.
Dengue
- Caused by a virus.
- Spread by the female Aedes mosquito (recognisable by white stripes on its legs).
- Symptoms: High fever, severe headache, pain behind the eyes, joint pain, rash.
- Prevention: Prevent mosquito bites, especially during daytime (Aedes bites during the day).
5. Prevention
Personal protection
- Sleep under a mosquito net (especially insecticide-treated nets).
- Wear full-sleeved clothes and long pants.
- Use mosquito repellent creams or sprays.
- Use mosquito coils or vapourisers (with adult supervision).
Community prevention
- Do not let water collect anywhere.
- Cover water storage containers tightly.
- Empty and clean coolers, flower pots, and pet water bowls weekly.
- Put oil or kerosene in stagnant drains (this kills larvae).
- Keep the surroundings clean and dry.
6. Sir Ronald Ross
Sir Ronald Ross was a British doctor working in India. In 1897, he discovered that female Anopheles mosquitoes transmit malaria between humans. For this discovery, he won the Nobel Prize in 1902. His work helped save millions of lives.
7. Activity corner
Activity 1: Walk around your neighbourhood. List all the places where water is standing (old tyres, open drains, coolers, buckets). Discuss with your family how to fix each one.
Activity 2: Draw the life cycle of a mosquito. Label all four stages.
Activity 3: Make a poster about dengue prevention. Display it in your school or neighbourhood.
8. Common mistakes
- Mistake: Thinking all mosquitoes spread diseases Fix: Only certain types of mosquitoes spread diseases. Male mosquitoes do not bite at all.
- Mistake: Believing mosquitoes breed in any water Fix: They breed in standing (stagnant) water, not in flowing water.
- Mistake: Thinking only female mosquitoes bite Fix: Actually, only female mosquitoes bite. They need blood to produce eggs. Male mosquitoes feed on plant nectar.
9. Key facts
- Mosquito life cycle: Egg -> Larva -> Pupa -> Adult (in standing water).
- Only female mosquitoes bite and spread diseases.
- Anopheles mosquito spreads malaria. Aedes mosquito spreads dengue.
- Sir Ronald Ross discovered the malaria-mosquito link in 1897.
- Prevention: No stagnant water, use nets and repellents.
- Cover water containers, clean coolers weekly.
10. Self-test
- How many stages are there in a mosquito's life cycle?
- What kind of water do mosquitoes breed in?
- Which mosquito spreads malaria?
- What does the Aedes mosquito look like?
- What is the best way to prevent mosquito breeding?
11. Answer key
-
How many stages are there in a mosquito's life cycle? Answer: Four stages — egg, larva (wriggler), pupa (tumbler), adult.
-
What kind of water do mosquitoes breed in? Answer: Standing (stagnant) water.
-
Which mosquito spreads malaria? Answer: The female Anopheles mosquito.
-
What does the Aedes mosquito look like? Answer: It has white stripes on its legs and body.
-
What is the best way to prevent mosquito breeding? Answer: Do not let water collect anywhere. Cover water containers, clean coolers weekly, and remove old tyres and containers that can collect water.
12. Quick revision
- Mosquito life cycle: Egg -> Larva -> Pupa -> Adult (in standing water).
- Only female mosquitoes bite.
- Malaria: Anopheles mosquito. Dengue: Aedes mosquito.
- Sir Ronald Ross: discovered malaria transmission.
- Prevention: no stagnant water, use nets, repellents, cover water.
- Community action is essential for mosquito control.
- Small actions (emptying a bucket) can prevent serious diseases.
