Learn Clearly
Important Concepts and notes
1. Health
Health is more than simply being free from disease. It includes
physical, mental and social well-being. Good health is supported by healthy habits,
positive thinking, proper nutrition, physical activity, adequate sleep and healthy
relationships.
2. Disease
A disease affects the normal functioning of the body or mind.
Symptoms are what a person feels, such as pain or tiredness, while
signs are changes that can be observed or measured, such as fever
or a rash.
3. Communicable Diseases
Diseases caused by pathogens that can spread from one person to
another are called communicable diseases. Examples include
typhoid, dengue, flu, chickenpox and COVID-19.
4. How Communicable Diseases Spread
Pathogens can enter the body through the air, contaminated food or water
and other routes. They may spread through coughing and sneezing, direct contact,
or indirectly through shared personal items. Some pathogens are carried by insects
such as mosquitoes and houseflies, which are called vectors.
5. Examples of Diseases and Their Spread
- Tuberculosis (TB): Caused by bacteria and affects the lungs.
- Hepatitis A: Caused by a virus and can spread through contaminated food or water.
- Cholera: Caused by bacteria and commonly spreads through contaminated food or water.
- Typhoid: Caused by bacteria and can spread through contaminated food or water.
- Malaria: Caused by a protozoan and transmitted by mosquitoes.
The chapter emphasises hygiene, safe drinking water, properly cooked food,
vaccination and other preventive measures for reducing the spread of diseases.
6. Non-Communicable Diseases
Non-communicable diseases (NCDs) are not caused by pathogens and
do not spread from one person to another. They are often linked to
lifestyle, diet and environmental factors.
Examples include diabetes, heart disease, cancer and asthma.
Unhealthy eating habits, insufficient physical activity and other lifestyle factors
can increase the risk of several NCDs.
7. Deficiency Diseases
Diseases caused by a lack of specific nutrients in the diet are
called deficiency diseases. They are also non-communicable.
8. Immunity
Immunity is the natural ability of the body to fight diseases.
The immune system protects the body against harmful pathogens.
9. Vaccination
Vaccines help protect against certain serious infections by
training the immune system to recognise and fight harmful germs. Vaccines may
contain weakened or dead pathogens, harmless parts of pathogens, or other
components that help the immune system develop protection.
10. Antibiotics
Antibiotics are medicines used against bacterial infections.
They work by targeting features of bacterial cells and therefore do not work
against viral infections such as common cold and flu.
11. Prevention of Diseases
Prevention is important for both communicable and non-communicable diseases.
Important preventive measures include maintaining personal hygiene,
clean surroundings, safe food and water, vaccination, healthy eating, regular
physical activity and adequate sleep.
12. Treatment and Management
Proper diagnosis and treatment are important for managing diseases.
For non-communicable diseases, treatment may involve medicines, lifestyle changes
and rehabilitation. Early diagnosis and continuous care can help control disease
progression and prevent complications.
Quick Comparison
| Communicable Diseases |
Non-Communicable Diseases |
| Caused by pathogens |
Not caused by pathogens |
| Can spread from one person to another |
Do not spread from one person to another |
| Examples: Typhoid, dengue, flu |
Examples: Diabetes, asthma, cancer |
Key Idea: Good health depends on understanding diseases,
preventing their spread, maintaining healthy habits and using appropriate
medical care when required.