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What a Disease Is
- A disease affects the normal working of the body or mind.
- It can happen when organs or organ systems stop working well.
- Some diseases are caused by germs called pathogens.
- Others come from poor nutrition or an unhealthy lifestyle.
Example 1 — A Cold
- A virus enters the body and causes a cold.
- The nose runs and the throat hurts.
- So a cold is a disease caused by a pathogen.
Example 2 — Diabetes
- Poor diet and little exercise can lead to diabetes.
- No germ is involved in this disease.
- So diabetes is a disease linked to lifestyle.
Important Points
- Disease-causing germs are called pathogens.
- Diseases are grouped by their cause and how they spread.
Definition — Disease
A disease is a condition that affects the normal working of the body or mind.
Definition — Pathogens
Pathogens are disease-causing germs like bacteria, viruses, fungi, worms, or protozoa.
Two Main Types of Diseases
- Non-communicable diseases do not spread from person to person.
- They are linked to lifestyle, diet, and environment.
- Communicable diseases are caused by pathogens.
- They can spread from one person to another.
Example 1 — Asthma
- Asthma is not caused by any germ.
- It does not spread to other people.
- So asthma is a non-communicable disease.
Example 2 — Chickenpox
- Chickenpox is caused by a virus.
- It spreads from a sick person to a healthy one.
- So chickenpox is a communicable disease.
Important Points
- Examples of communicable diseases: typhoid, dengue, flu, chickenpox, COVID-19.
- Today most deaths in India are caused by non-communicable diseases (NCDs).
Definition — Non-communicable Diseases
Diseases that are not caused by pathogens and do not spread from one person to another, like cancer, diabetes, or asthma.
Definition — Communicable Diseases
Diseases caused by pathogens that can spread from one person to another, like typhoid, dengue, and flu.
📋 NCERT Question 1 — Group the diseases shown
Group these diseases as communicable or non-communicable: cold and flu, typhoid, diabetes, asthma, chickenpox.
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📋 NCERT Question 2 — Identify non-communicable diseases
From typhoid, asthma, diabetes, and measles, identify the two non-communicable diseases. (MCQ)
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