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Chapter 3 -Health: The Ultimate Treasure

Key Terms

What is Health?

According to the World Health Organization (WHO), health is a state of complete physical, mental, and social well-being, not merely the absence of disease.

A healthy person:

Health and happiness are closely connected. Good health improves mood and quality of life, while happiness supports overall well-being.

Ayurveda’s View of Health

Ayurveda considers health as a balance between the body, mind, and surroundings. It promotes:

Healthy and Unhealthy Habits

Healthy Habits

Unhealthy Habits

Environmental Health

The environment significantly affects health. Some of the important environmental factors that determines health are Clean air and water,proper sanitation and waste disposal and pollution control.

Air Quality Index (AQI)

The Air Quality Index (AQI) is a standardized, color-coded scale used by governments and environmental agencies to communicate daily air pollution levels. It transforms complex data of major air pollutants into a single, easy-to-understand number to quickly indicate associated health risks..

Diseases and its classification

A disease is any harmful deviation from the normal functioning of the body or mind. Diseases are generally categorized into distinct types based on their causes, transmission, and duration.

Infectious Diseases

Caused by microscopic organisms (pathogens) like bacteria, viruses, fungi, or parasites. They can often be spread from person to person.

  1. Viral: Common cold, COVID-19, influenza, and HIV.
  2. Bacterial: Tuberculosis, strep throat, and urinary tract infections.
  3. Fungal: Athlete’s foot, toenail fungus, and ringworm.
  4. Parasitic: Malaria (spread by mosquitoes) and amoebiasis.

Non-Infectious (Non-Communicable) Diseases

These are not caused by pathogens and cannot be spread from person to person. They are generally linked to genetics, lifestyle, or environment.

  1. Cardiovascular Disease: Heart attacks, stroke, and high blood pressure.
  2. Chronic Respiratory Diseases: Asthma and COPD.
  3. Cancer: Abnormal, uncontrolled cell growth.
  4. Diabetes: Conditions where the body cannot properly process glucose.

Classification of Diseases

Type Disease Classification Causative Organism / Cause Symptoms Treatment
Communicable Diseases Common Cold Viral infection Rhinovirus Runny nose, sore throat, sneezing, cough Rest, fluids, symptomatic treatment
Influenza (Flu) Viral infection Influenza virus Fever, body ache, fatigue, cough Antiviral drugs, rest, hydration
Typhoid Bacterial infection Salmonella typhi High fever, weakness, stomach pain Antibiotics, hydration, rest
Malaria Protozoan infection Plasmodium (via Anopheles mosquito) High fever with chills, sweating, headache Antimalarial drugs
Chickenpox Viral infection Varicella-zoster virus Itchy skin rash, fever, fatigue Antiviral drugs, calamine lotion, rest
Non-Communicable Diseases Diabetes Metabolic disorder Not caused by pathogens (insulin deficiency/resistance) Frequent urination, thirst, fatigue Insulin therapy, diet control, exercise
Hypertension Cardiovascular disorder Lifestyle-related (stress, diet, genetics) Headache, dizziness, chest pain Medication, low-salt diet, exercise
Asthma Respiratory disorder Allergic triggers, environmental factors Breathing difficulty, wheezing, coughing Inhalers, avoiding triggers
Heart Disease Cardiovascular disorder Blocked arteries, lifestyle factors Chest pain, fatigue, shortness of breath Medication, surgery, lifestyle changes
Obesity Metabolic condition Overeating, lack of exercise Excess body weight, fatigue Diet control, exercise, behavior therapy

Hereditary & Genetic Diseases

These are passed down from parents to children through altered or mutated genes.Examples: Sickle cell anemia, cystic fibrosis, and Down syndrome.

Deficiency Diseases

Caused by a lack of essential vitamins or minerals in the daily dietExamples: Scurvy (Vitamin C), anemia (Iron), and rickets (Vitamin D).

Autoimmune Diseases

Conditions where the body’s immune system mistakenly attacks healthy cells and tissues. Examples: Type 1 diabetes, rheumatoid arthritis, and lupus.

Classification of Diseases by Duration

Diseases can also be classified by how long they last:

Communicable Diseases

Communicable diseases are caused by pathogens and can spread from one person to another.

Pathogens of Communicable Diseases

Disease-causing organisms include:

Modes of Transmission

Examples

Vectors

A vector is an organism that carries and transmits pathogens, such as mosquitoes spreading malaria and dengue.

Non-Communicable Diseases

Non-communicable diseases (NCDs) are not caused by pathogens and do not spread between people.

Causes

Examples

The number of people with diabetes and heart disease is increasing in India due to sedentary lifestyles and increased consumption of processed foods.

Deficiency Diseases

These are diseases caused by a lack of essential nutrients.

Examples

Preventing Communicable Diseases

Community sanitation campaigns, such as those implemented in Odisha, have helped reduce the spread of infectious diseases.

Immunity and Vaccination

Immunity

Immunity is the body's natural ability to resist and fight diseases.

Acquired Immunity

Protection developed after:

Vaccines

Vaccines train the immune system to recognize and fight specific pathogens before they cause disease.

Vaccines help prevent diseases such as:

Vaccines prevent diseases; they do not cure existing infections.

Antibiotics

Antibiotics are medicines used to treat bacterial infections.They Kill bacteria or stop their growth but they do not work against viral infections.

Antibiotic Resistance

Antibiotic resistance occurs when bacteria survive and continue multiplying despite antibiotic treatment. It is caused due to the overuse of antibiotics, incorrect use of antibiotics or not completing prescribed courses. It can be prevented or reduced by the use of antibiotics only when prescribed and follow the doctor's instructions carefully.

Traditional Systems of Medicine

India has several traditional healthcare systems, incsuch as Ayurveda, Siddha, Homeopathy, and Unani. These systems promote overall well-being and healthy lifestyles but may not be suitable for treating all diseases.

Management of Diseases

Managing Non-Communicable Diseases

NCDs are managed through Medicines,healthy diet,regular exercise,lifestyle changes, early diagnosis and treatment

Important Scientists

Health and Well-being

Activity 1: Let Us Read

A Grade 8 student moved to a new school in another city. With no friends and busy parents, he felt lonely. To cope, he spent more time on his phone and social media, but this made him feel worse. He stopped trying to make friends, had headaches, lost weight, and could not sleep well. A doctor advised him to reduce screen time and meet a counsellor. The school counselor helped him make friends and improve his health.

Think and Reflect:

The World Health Organization (WHO) defines health as a “state of complete physical, mental, and social well-being, not merely the absence of disease.”
A healthy person:

Ayurveda and Health

Ayurveda teaches that true health is a balance of body, mind, and surroundings. This can be achieved by:

How Can We Stay Healthy?

Activity 2: Let Us List

Good habits to follow:

Think: Which of these habits are already part of your routine? Which ones would you like to start?

Habits that are not healthy:

Healthy habits support both body and mind. Discuss your findings with your friends and teacher.

Maintain a Healthy Lifestyle

To stay healthy:

Keep the Environment Clean

Activity 3: Let Us Compare

Look at Figures A and B. Which playground would you like to play in, and why?

Most of us would choose Figure A, because it is clean, well-maintained, and looks inviting. Figure B is polluted, dirty, unhygienic, and full of flies and mosquitoes. Living in such an environment can make people fall sick more often.

Reflection:


In addition to following good habits and a healthy lifestyle, we must also keep ourselves and our surroundings clean.

In cities, air pollution from vehicles and factories can cause problems such as coughing or asthma. The Air Quality Index (AQI) helps us measure how clean or polluted the air is. A cleaner environment keeps us healthier and makes us feel better.

Remember:

Health is not just about the body. Feelings and relationships matter too. Even if we eat well and live in a clean place, we may not feel good if we are lonely or upset. Spending time with friends and family, talking, laughing, and having fun keeps our minds healthy.

How Do We Know That We Are Unwell?

Our body usually functions in a certain way to maintain health. When something goes wrong, we may feel symptoms or show signs of illness.

Term

Meaning

Examples

Symptom

What we feel

Pain, tiredness, dizziness

Sign

What can be seen or measured

Fever, rash, high blood pressure, swelling

These help doctors understand what might be wrong and decide on treatment.

Activity 5: Let Us Survey

Find out the three most common lifestyle-related diseases in your neighbourhood. Gather information from doctors, nurses, health workers, teachers, family members, books, or trusted health websites.

For each disease, identify:

Record your findings in Table 2.

Activity 6: Let Us Read

Odisha's Community-Led Sanitation Campaign

In Bhadrak district of Odisha, a community sanitation campaign encouraged people to build and use toilets. This reduced open defecation and led to fewer cases of diarrhoea and infections among children.

What Can We Learn?

Immunity: The Body's Defence System

Some people fall sick more often than others even when they live in the same environment. This is because immunity differs from person to person.

Immunity

Immunity is the body's natural ability to fight diseases.

The immune system protects us by:

Vaccines and Acquired Immunity

Vaccines help train the immune system to recognize and fight harmful pathogens before they cause disease.

Acquired Immunity

Acquired immunity develops:

How Vaccines Work

Vaccines may contain:

The immune system learns to recognize these components and develops protection without causing the disease.

Examples of Vaccine-Preventable Diseases

Important Fact

Vaccines are preventive, not curative. They help prevent diseases but do not cure a disease once a person becomes sick.

Edward Jenner and the First Vaccine

Smallpox was a deadly disease that caused painful blisters and killed millions of people. English doctor Edward Jenner noticed that milkmaids who had previously contracted cowpox rarely developed smallpox. He observed that milkmaids who had cowpox seemed protected from smallpox. He understood that material from cowpox blisters could provide protection against smallpox. To prove this, Jenner introduced cowpox material into a young boy and later exposed him to smallpox. The boy did not develop smallpox.

Application

This discovery led to the world's first vaccine and eventually helped eradicate smallpox globally.

Traditional Indian Method of vaccination : Variolation

Before modern vaccines, India practiced variolation.

This method involved:

People who performed this procedure were known as teekedaars.

India's Contribution to Vaccine Production

India's Contribution to Vaccine Production

India is one of the world's largest vaccine producers. Indian vaccine manufacturers supply vaccines to many countries and they played a major role during the COVID-19 pandemic while they continue to support global health programs Dr. Maharaj Kishan Bhan was a renowned Indian scientist and physician.

His contributions include:

Treatment of Infectious Diseases

If the immune system cannot successfully fight an infection, medical treatment may be required.

Antibiotics

Antibiotics are medicines used to treat bacterial infections. They work by killing bacteria or by stopping bacterial growth. Antibiotics work against bacteria, but they do not work against viruses and protozoa.

Discovery of Penicillin

In 1928, Alexander Fleming discovered penicillin, the first antibiotic. While studying bacteria, Fleming noticed that a mould growing on a petri dish prevented bacterial growth. He realized the mould produced a substance that killed bacteria, leading to the discovery of penicillin. This breakthrough revolutionized medicine and saved millions of lives.

Antibiotic Resistance

Antibiotic resistance occurs when bacteria survive and continue multiplying despite antibiotic treatment.

It is caused by:

Effects

Activity 7: Let Us Infer

Study the infographic on antibiotic resistance and discuss:

Preventing Antibiotic Resistance

Responsible use helps keep antibiotics effective for future generations.

Traditional Medicine Systems

India has a rich tradition of healthcare systems, including:

Features of These Systems

However, they may not be effective for all diseases or at every stage of illness.

Managing Non-Communicable Diseases (NCDs)

Treatment of NCDs focuses on controlling symptoms and improving quality of life.

Common Approaches

Importance of Early Diagnosis

Early detection and continuous care can:

INTEXT SOLUTIONS

NCERT Probe and Ponder Questions (Page 28)

  1. Represent the following data in a bar graph.

Answer:

The body responds to a common cold (caused by viruses) through the immune system. Symptoms like a runny nose, sore throat, or cough occur as the body fights the infection. The immune system produces antibodies to neutralize the virus, and white blood cells attack infected cells. Rest, hydration, and sometimes medication (e.g., for fever) help recovery.

Dengue Cases Graph
  1. We rarely see cases of smallpox or polio these days, but diseases like diabetes and heart problems are more common. Why?
    Answer: Smallpox and polio have been nearly eradicated due to widespread vaccination programs. In contrast, non-communicable diseases (NCDs) like diabetes and heart problems are increasing due to modern lifestyle factors such as unhealthy diets, lack of exercise, stress, and longer life expectancies.
  2. Could climate change lead to new types of diseases?
    Answer: Yes, climate change can lead to new or increased disease risks. Warmer temperatures and changing weather patterns can expand the range of disease-carrying vectors like mosquitoes, alter water quality, and create conditions for new pathogens to emerge or spread more easily.
  3. How do emotions like stress or worry affect us and make us sick?
    Answer: Stress or worry can weaken the immune system by releasing hormones like cortisol, making the body more susceptible to infections. Chronic stress can also contribute to diseases like high blood pressure or diabetes.
  4. Why do some groups of people get affected more than others during disease outbreaks?
    Answer: Some groups are more affected due to factors like weaker immunity, poor living conditions, malnutrition, or preexisting health issues.

Answer: Communicable Diseases

 Non- Communicable Diseases

Diseases can be broadly grouped into communicable and non-communicable diseases. From the options given below, identify the non-communicable diseases.


(i) Typhoid
(ii) Asthma
(iii) Diabetes
(iv) Measles
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer:(b) (ii) and (iii) are NCDs

Answer:(b) (ii) and (iii) are NCDs

  1. There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing. What immediate actions should the school take to prevent further spread? If your classmate, who shares the bench with you, starts showing symptoms of the flu, how can you respond in a considerate way without being rude or hurtful? How can you protect yourself and others from getting infected in this situation?

Answer: The school should close temporarily, sanitise classrooms, and encourage sick students to stay home to prevent further spread. You can politely suggest that your classmate see a doctor and take a rest at home, and offer to share notes with them. To protect yourself and others, wash your hands frequently, avoid close contact, and wear a mask.

  1. Your family is planning to travel to another city where malaria is prevalent.

Answer: To protect our family from malaria during travel, focus on preventing mosquito bites and taking prescribed preventative medication.

Explain to your sibling that mosquitoes spread malaria and that nets or repellents protect by blocking bites. If travelers ignore health advisories in such areas, they risk malaria infection, severe illness, or even death.

  1. Your uncle has started smoking just to fit in with his friends, even though it is well known that smoking can seriously harm health and even cause death.

Answer: Dear Uncle, I care about your health and well-being, and I want to talk to you about smoking. It’s well-known that smoking can lead to serious health issues, including heart disease and lung cancer. Quitting smoking can greatly improve your health and quality of life.

  1. Saniya claims to her friend Vinita that “Antibiotics can cure any infection, so we don’t need to worry about diseases.” What question(s) can Vinita ask her to help Saniya understand that her statement is incorrect?
    Answer:     Saniya’s Statement is Wrong because:

Vanita can ask Saniya, Did you know that antibiotics don’t work on viruses like the flu or measles? They’re only useful for bacterial infections. Also, if we take antibiotics when we don’t need them, they might stop working when we really do. That’s why doctors are careful about prescribing them.”

  1. The following table contains information about the number of dengue cases reported in a hospital over one year:

    2. The table shows the number of dengue cases reported each month:

    Dengue Cases Reported by Month
    Month Cases
    January10
    February12
    March15
    April18
    May22
    June40
    July65
    August65
    September65
    October30
    November30
    December20


    Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following:

    Dengue Cases Graph

    Answer:

    1. Imagine you are in charge of a school health campaign. What key messages would you use to reduce communicable and non-communicable diseases?
      Answer:       Key messages for a school health campaign to reduce communicable and non-communicable diseases include washing hands regularly, eating a healthy diet, exercising daily, getting vaccinated, and avoiding smoking.
    2. It is recommended that we not take an antibiotic for a viral infection like a cold, a cough, or the flu. Can you provide the possible reason for this recommendation?
      Answer:       The recommendation to avoid antibiotics for a viral infection like a cold, cough, or flu is because antibiotics do not work on viruses, which cause these illnesses.
    3. Which disease(s) among the following may spread if drinking water gets contaminated by the excreta from an infected person? (Hepatitis A, Tuberculosis, Poliomyelitis, Cholera, Chickenpox)

    Answer: The diseases that may spread if drinking water gets contaminated by the excreta from an infected person are Hepatitis A, Poliomyelitis, and Cholera.

    1. When our body encounters a pathogen for the first time, the immune response is generally low, but on exposure to the same pathogen again, the immune response by the body is much more compared to the first exposure. Why is it so?
      Answer: When our body faces a pathogen (like a virus or bacteria) for the first time, our immune system needs time to:

    This first reaction is called the primary immune response, and it’s usually slow and weak.
    When the same pathogen enters our body again:

    This is called the secondary immune response, and it’s faster, stronger, and more effective.

    Activity 3.1: Let us Read (Page 29)

    1. What was the cause of the boy’s health problems?
      Answer: The boy’s health problems were caused by a combination of loneliness, lack of social support (due to busy parents and no friends), and excessive screen time. His isolation and reliance on social media worsened his mental state, leading to physical symptoms like headaches, weight loss, and insomnia. The absence of a supportive environment and healthy coping mechanisms contributed significantly.
    1. How did his habits and surroundings affect his well-being?
      Answer:

    Activity 3.3: Let us Compare (Page 31)

    Question 1. Look at Fig. (a) and Fig. (b). Which playground would you like to play in, and why?

    Answer: Preferred Playground: Most students would prefer to play in the playground shown in Fig. (a). Reason:

    Activity 3.6: Let us Read (Page 37)

    1. What do you infer from this case study?
      The case study shows that improving sanitation, such as building and using toilets, can greatly reduce open defecation and improve health, especially for children. The significant drop in diarrhoea and infections suggests that clean sanitation prevents the spread of communicable diseases caused by pathogens in contaminated environments (e.g., through water or soil)
    1. Find out about such community campaigns held in your location. Share in your class and discuss with your peers about the impact of such initiatives.
      Answer: Finding Campaigns: (This depends on local context; example based on general knowledge and the document’s focus on India):

    Sharing and Discussion:

    Impact: Share that such campaigns reduce diseases like diarrhea, cholera, and typhoid by improving access to clean water and toilets. For instance, the Odisha campaign’s success in lowering child infections shows how sanitation saves lives and reduces healthcare costs.

    Discussion Points: