Diseases and Prevention — REET EVS Notes
This page covers the classification of diseases (communicable vs non-communicable), the microorganisms that cause them (bacteria, viruses, protozoa, fungi), and prevention measures. Matching a disease to its causative organism is a pattern REET tests regularly.
- 1 question in REET 2024
- Class 1–5 level
- 6 min read
How this topic is asked in REET
REET 2024 included a matching question that asked candidates to correctly pair a virus-caused disease (chickenpox), a bacteria-caused disease (tuberculosis), a protozoa-caused disease (malaria) and a malnutrition-caused disease (kwashiorkor). This shows that classifying diseases by their 'causative agent' (bacteria/virus/protozoa/fungus/malnutrition) is the most important skill for REET on this topic.
Classification of Diseases by Causative Agent
| Agent | Example diseases |
|---|---|
| Bacteria | Tuberculosis/TB, typhoid, cholera, leprosy |
| Virus | Chickenpox, measles, influenza (flu), polio, dengue, COVID-19 |
| Protozoa | Malaria (Plasmodium), amoebiasis, kala-azar |
| Fungus | Ringworm, itching-related skin diseases |
| Malnutrition | Kwashiorkor, marasmus, night blindness |
| Worms (helminths) | Roundworm, tapeworm — usually spread through contaminated food/soil contact |
The REET 2024 question was built on exactly this classification — make sure you have at least one solid example locked in for each category.[Source 1]
Communicable and Non-Communicable Diseases
Communicable diseases are those that spread from one person to another through direct contact, air, contaminated water/food, or insects (such as mosquitoes) — like tuberculosis, flu, and malaria. Non-communicable diseases, by contrast, do not spread from person to person; they arise from lifestyle, heredity, or nutritional deficiency — like diabetes, high blood pressure, and heart disease.
Among mosquito-borne (vector-borne) diseases, malaria is spread by the female Anopheles mosquito, while dengue and chikungunya are spread by the Aedes mosquito — so controlling mosquitoes (preventing stagnant water, using mosquito nets) is key to preventing these diseases.
Communicable diseases can also be classified by how they spread — air-borne diseases (like tuberculosis, flu, common cold) spread through breathing; water-borne diseases (like typhoid, cholera, diarrhoea) spread through contaminated water/food; and contact-borne diseases (like scabies, ringworm) spread through direct skin contact or shared items. REET can occasionally build a question around classifying a disease by its 'mode of spread' too, so it's worth remembering both the causative organism and how it spreads.
Common Symptoms of a Few Diseases
- Malaria
- High fever with chills and shivering, fever that comes and goes repeatedly
- Typhoid
- A slowly rising, sustained fever, stomach pain, weakness
- Chickenpox
- Red, fluid-filled spots on the body, mild fever, itching
- Diarrhoea
- Frequent loose stools, which can deplete the body of water and salts (electrolytes)
- Tuberculosis (TB)
- A persistent cough lasting more than two weeks, mild evening fever, weight loss and loss of appetite — these symptoms should be checked immediately
Clean Water, Hygiene, and Preventing Diarrhoeal Disease
The most effective ways to prevent diseases spread by contaminated water and food (like typhoid, cholera, diarrhoea) are drinking boiled or filtered water, washing hands before eating, and avoiding open defecation. When diarrhoea does occur, the very first and most essential treatment is giving an ORS (Oral Rehydration Solution) solution, which immediately replaces the water and salts lost from the body.
Ensuring clean toilets and safe drinking water in schools is considered the first line of defence against communicable diseases — which is exactly why the EVS syllabus places 'hygiene' and 'diseases and prevention' next to each other.
Immunisation — the Main Route to Prevention
Under India's National Immunisation Programme, children are given free vaccines against diseases like polio, BCG (protecting against tuberculosis), measles, and DPT (diphtheria-pertussis-tetanus) from birth through adolescence. Special campaigns like Mission Indradhanush are run to reach children who missed out on routine immunisation.
School teachers play an important role in spreading health awareness and information about regular immunisation among children, which is why this topic in the REET syllabus is also tied to a teacher's practical responsibility. In addition, periodic school health check-up camps and growth monitoring also succeed largely with teachers' cooperation.
India's Universal Immunisation Programme (UIP) was launched in 1985, and remains one of the largest public health programmes in the world. Thanks to the sustained efforts of the Pulse Polio campaign, India was declared 'polio-free' by the World Health Organization in 2014 — a clear demonstration that even serious communicable diseases can be eliminated at the root through collective, sustained immunisation.
How to Teach This to Children
Classroom activity
Demonstrate the '6 steps of handwashing' (the WHO handwashing technique) — this simple habit has proven to be one of the most effective ways to prevent many communicable diseases.
Teaching aids
Make disease-agent-symptom flash cards and play a 'matching game' where children pair each disease with its correct causative agent (bacteria/virus/protozoa).
Common misconception
Children often assume all diseases are 'caused by germs' in the same way. Teachers should clarify that non-communicable diseases like diabetes aren't caused by any germ, but by lifestyle and heredity.
Local example
Discuss a recent seasonal illness in your own village/town (such as dengue during the monsoon or flu in winter) and ask children what causes it and how to prevent it — this grounds the lesson in local experience.
Assessment idea
Ask children, 'What precautions does your family take when you get a fever?' — this discussion assesses their practical understanding of disease prevention.
Life-skills activity
Demonstrate the simple process of preparing an ORS solution (the correct amount of salt-sugar-water) in class — a life-saving practical skill that's useful at home too.
General Measures to Build Immunity
A balanced diet, adequate sleep, regular physical activity and good hygiene habits all strengthen the body's natural immunity, which reduces both the likelihood and the severity of infections. The EVS curriculum helps children understand that alongside 'treatment when sick', building 'habits that prevent illness in the first place' matters just as much — this is called preventive health.
Memory trick
A trick for remembering disease agents — 'Virus gives Viral diseases (chickenpox, measles, flu), Bacteria gives TB-typhoid, Protozoa gives malaria-kala-azar, Fungus gives ringworm'. In matching questions like REET 2024's, keeping one 'locked-in' example ready for each agent lets you spot the right pair instantly.
REET 2024 Questions (Solved)
Question 121
Match the following and choose the correct answer. (i) Viral disease (a) Tuberculosis (ii) Bacterial disease (b) Malaria (iii) Protozoan disease (c) Kwashiorkor (iv) Disease due to malnutrition (d) Chicken pox (i) (ii) (iii) (iv)
- A(a) (d) (c) (b)
- B(d) (a) (b) (c)
- C(c) (b) (a) (d)
- D(b) (c) (d) (a)
Explanation
चिकन पॉक्स वायरस (Varicella-zoster) से, तपेदिक (TB) जीवाणु (Mycobacterium tuberculosis) से, मलेरिया प्रोटोज़ोआ (Plasmodium) से और क्वाशियोरकर प्रोटीन की कमी (कुपोषण) से होता है। अतः सही मिलान (i)-(d), (ii)-(a), (iii)-(b), (iv)-(c) है, जो विकल्प (B) है।
Practice Questions
Question 1
Tuberculosis (TB) is caused by which agent?
- Aविषाणु
- Bजीवाणु
- Cप्रोटोज़ोआ
- Dकवक
Explanation
Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis.
Question 2
Which of the following diseases is caused by a virus?
- Aटाइफाइड
- Bमलेरिया
- Cखसरा
- Dदाद
Explanation
Measles is a virus-caused disease. Typhoid is caused by bacteria, malaria by protozoa, and ringworm by fungus.
Question 3
Which mosquito spreads malaria?
- Aएडीज़ मच्छर
- Bमादा एनाफ़िलीज़ मच्छर
- Cक्यूलेक्स मच्छर
- Dघरेलू मक्खी
Explanation
Malaria spreads through the bite of the female Anopheles mosquito, which carries the Plasmodium parasite into the human bloodstream.
Question 4
Diabetes belongs to which category of disease?
- Aसंचारी रोग
- Bअसंचारी रोग
- Cविषाणु जनित रोग
- Dप्रोटोज़ोआ जनित रोग
Explanation
Diabetes is a non-communicable disease, linked to lifestyle and heredity, and it does not spread from one person to another.
Question 5
The BCG vaccine is given to prevent which disease?
- Aपोलियो
- Bखसरा
- Cक्षय रोग (तपेदिक)
- Dमलेरिया
Explanation
The BCG vaccine is given to newborns to protect against tuberculosis.
Question 6
Ringworm disease is caused by which agent?
- Aजीवाणु
- Bविषाणु
- Cकवक
- Dप्रोटोज़ोआ
Explanation
Ringworm is a skin disease caused by a fungus.
Question 7
How do communicable diseases spread?
- Aकेवल आनुवंशिकता से
- Bसंपर्क, हवा, दूषित जल-भोजन या कीट के माध्यम से
- Cकेवल जीवनशैली से
- Dकभी नहीं फैलते
Explanation
Communicable diseases spread from one person to another through direct contact, air, contaminated water/food, or insects.
Question 8
Which is the most effective practical classroom activity for preventing communicable diseases?
- Aकेवल किताब से परिभाषा पढ़ाना
- Bहाथ धोने के सही तरीके का व्यावहारिक प्रदर्शन करवाना
- Cटॉपिक को छोड़ देना
- Dकेवल रोगों के नाम रटवाना
Explanation
Hand hygiene — washing hands the correct way — is one of the simplest and most effective practical ways to prevent many communicable diseases, and something young children can be taught as a habit.
Question 9
What is the most effective measure for preventing mosquito-borne (vector-borne) diseases?
- Aकेवल दवा खाना
- Bआसपास जलभराव रोकना व मच्छरदानी का उपयोग करना
- Cकुछ न करना
- Dकेवल ठंडा पानी पीना
Explanation
Mosquitoes breed in stagnant water, clean or dirty, so preventing waterlogging and using mosquito nets is most effective against diseases like malaria and dengue.
Question 10
Kwashiorkor falls under which category?
- Aविषाणु जनित रोग
- Bजीवाणु जनित रोग
- Cकुपोषण जनित रोग
- Dप्रोटोज़ोआ जनित रोग
Explanation
Kwashiorkor is a malnutrition-caused disease, resulting from severe protein deficiency — not from any microorganism.
Frequently Asked Questions
What's the difference between communicable and non-communicable diseases?+
Communicable diseases spread from one person to another (like tuberculosis, flu), while non-communicable diseases don't spread and are linked to lifestyle/heredity (like diabetes, high blood pressure).
What causes malaria?+
Malaria is caused by a protozoan parasite called Plasmodium, transmitted to humans through the bite of the female Anopheles mosquito.
Which disease does the BCG vaccine protect against?+
The BCG (Bacillus Calmette-Guérin) vaccine is given to newborns to protect against tuberculosis.
Which mosquito spreads dengue and chikungunya?+
Dengue and chikungunya spread through the bite of the Aedes mosquito, which typically bites during the day and breeds in clean, stagnant water.
What's the first treatment for diarrhoea?+
The first and most essential treatment for diarrhoea is giving an ORS (Oral Rehydration Solution), which immediately replaces the water and salts lost from the body.
What is Mission Indradhanush related to?+
Mission Indradhanush is a special campaign to reach immunisation to children who missed out on the routine immunisation programme; it was launched in 2014.
What are some general ways to boost immunity?+
A balanced diet, adequate sleep, regular physical activity and good hygiene habits all naturally strengthen the body's immunity.
When was India declared polio-free?+
India was declared polio-free by the World Health Organization in 2014, the result of years of sustained effort through the Pulse Polio campaign.
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Official Sources
Change Log
- 17 September 2026 — English page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked