Understanding health, diseases, and how to stay healthy
Health is a state of complete physical, mental, and social well-being, and not merely the absence of disease.
Health is like a well-functioning car. It's not just about the engine working (no disease), but also having good tires (physical fitness), a comfortable interior (mental well-being), and being able to travel with friends (social well-being). All parts working together make a truly "healthy" car!
1. Physical Health: Body functioning properly, no
diseases, good fitness
2. Mental Health: Mind is at peace, no stress or
anxiety, good emotional state
3. Social Health: Good relationships, harmony
with society, financial stability
All three are equally important! A person is truly healthy only
when all three are good.
Imagine a student who:
• Has no physical illness (physically healthy) ✓
• But is always stressed about exams (mentally unhealthy) ✗
• And has fights with friends (socially unhealthy) ✗
This student is NOT truly healthy, even though there's no physical
disease! Health means all three aspects should be good.
Disease is a condition that impairs the normal functioning of body organs and systems. It makes us feel sick and unable to perform daily activities properly.
| Feature | Acute Diseases | Chronic Diseases |
|---|---|---|
| Duration | Short duration (few days to weeks) | Long duration (months to years) |
| Onset | Sudden onset | Gradual onset |
| Effect on Body | Sudden severe effect | Slow, prolonged effect |
| Recovery | Quick recovery | Takes long time, sometimes no complete cure |
| Examples | Cold, cough, fever, diarrhea | Diabetes, tuberculosis, asthma, cancer |
Acute disease is like a sudden storm - comes
quickly, causes havoc, and goes away soon.
Chronic disease is like climate change - develops
slowly, lasts long, and has long-term effects.
Based on causative factors, diseases are of two types:
1. Infectious Diseases (Communicable)
2. Non-infectious Diseases (Non-communicable)
Diseases caused by microorganisms (germs) that can spread from one person to another. These microorganisms are called pathogens.
Pathogens = Disease-causing microorganisms (bacteria, viruses, fungi, protozoa, worms)
• Single-celled microorganisms
• Can be killed by antibiotics
• Diseases: Tuberculosis (TB), Typhoid, Cholera,
Pneumonia
• Spread: Air, water, food, contact
• Caused by bacteria Mycobacterium tuberculosis
• Affects lungs mainly
• Spreads through air (coughing, sneezing)
• Symptoms: Continuous cough, chest pain, blood in sputum, weight
loss
• Treatment: Antibiotics for 6-9 months
• Prevention: BCG vaccine
• Much smaller than bacteria
• Cannot be killed by antibiotics
• Diseases: Common cold, flu, COVID-19, dengue,
AIDS, polio
• Spread: Air, water, vectors, bodily fluids
• Caused by viruses (rhinoviruses)
• Affects nose and respiratory tract
• Spreads through air (sneezing, coughing)
• Symptoms: Runny nose, sneezing, sore throat, cough
• No specific medicine - body fights it naturally
• Rest and fluids help recovery
• Single-celled animals
• Often spread by vectors or contaminated water
• Diseases: Malaria, Amoebiasis (dysentery),
Sleeping sickness
• Spread: Mosquitoes, contaminated water, flies
• Caused by protozoan Plasmodium
• Spread by female Anopheles mosquito
• Affects liver and red blood cells
• Symptoms: Recurring fever with chills, sweating, headache
• Treatment: Antimalarial drugs
• Prevention: Mosquito nets, preventing mosquito breeding
• Cause mostly skin infections
• Grow in warm, moist areas
• Diseases: Ringworm, Athlete's foot
• Spread: Contact with infected person or
surfaces
• Parasitic worms living inside body
• Diseases: Roundworm, Tapeworm, Pinworm
infections
• Spread: Contaminated food, water, soil
• Pathogens spread through droplets in air
• When infected person coughs, sneezes, or talks
• Diseases: Common cold, flu, tuberculosis,
COVID-19
• Prevention: Cover mouth when coughing, wear
mask, good ventilation
• Pathogens present in contaminated water
• Drinking or using polluted water
• Diseases: Cholera, typhoid, hepatitis A,
amoebiasis
• Prevention: Drink clean/boiled water, proper
sanitation
• Pathogens present in contaminated food
• Eating spoiled or contaminated food
• Diseases: Food poisoning, typhoid, hepatitis
A
• Prevention: Wash hands before eating, eat
freshly cooked food
• Touching infected person or contaminated surfaces
• Sharing personal items
• Diseases: Skin infections (ringworm), COVID-19,
AIDS
• Prevention: Maintain hygiene, don't share
personal items
• Organisms that carry pathogens from one host to another
• Common vectors: Mosquitoes, flies, rats,
dogs
• Diseases: Malaria, dengue (mosquitoes), plague
(rats), rabies (dogs)
• Prevention: Keep surroundings clean, use
mosquito nets, control vector population
Vectors are like delivery people! They pick up disease germs from one person/place and deliver them to another person. Mosquitoes are the most common "disease delivery agents"!
Diseases that are NOT caused by pathogens and do NOT spread from person to person. They are caused by factors like lifestyle, genetics, environment, or deficiencies.
• Present from birth due to defects in genes
• Inherited from parents
• Examples: Color blindness, hemophilia, sickle
cell anemia
• Caused by lack of essential nutrients
• Due to poor diet or malnutrition
• Examples:
- Vitamin A deficiency → Night blindness
- Vitamin C deficiency → Scurvy
- Vitamin D deficiency → Rickets
- Iron deficiency → Anemia
- Iodine deficiency → Goiter
• Caused by unhealthy lifestyle habits
• Risk factors: Smoking, alcohol, junk food, no
exercise, stress
• Examples: Diabetes, heart disease, obesity,
high blood pressure
• Body cannot properly use glucose (sugar)
• Either pancreas doesn't make insulin, or body can't use it
properly
• Causes: Obesity, family history, unhealthy diet, lack of
exercise
• Symptoms: Frequent urination, increased thirst, tiredness, slow
healing
• Prevention: Healthy diet, regular exercise, maintain healthy
weight
• Organs deteriorate over time
• Usually occur with aging
• Examples: Alzheimer's disease, Parkinson's
disease, osteoporosis
• Uncontrolled growth of abnormal cells
• Can occur in any part of body
• Causes: Smoking, tobacco, radiation, genetic factors, certain
infections
• Types: Blood cancer (leukemia), lung cancer,
breast cancer, etc.
| Feature | Infectious Diseases | Non-Infectious Diseases |
|---|---|---|
| Cause | Microorganisms (pathogens) | Lifestyle, genetics, deficiencies |
| Spread | Can spread from person to person | Cannot spread from person to person |
| Duration | Usually acute (short duration) | Usually chronic (long duration) |
| Prevention | Hygiene, vaccines, avoiding contact | Healthy lifestyle, balanced diet |
| Examples | Malaria, TB, cholera, flu | Diabetes, cancer, heart disease |
The immune system is our body's defense system that fights against disease-causing germs and protects us from infections.
Immune system is like an army protecting a country! White blood cells are soldiers that fight enemy invaders (germs). Some soldiers remember enemies (memory cells) so they can fight faster if the same enemy attacks again!
1. Skin: Acts as a protective wall, prevents
entry of germs
2. Mucus in nose: Traps germs and dust
particles
3. Tears: Wash away germs from eyes
4. Stomach acid: Kills germs that enter with
food
5. Saliva: Contains chemicals that kill germs
If germs cross physical barriers:
• White blood cells attack and destroy them
• Antibodies are produced to fight specific
germs
• Body shows inflammation (redness, swelling,
heat) at infection site
• Fever develops - body's way of fighting
infection (high temperature kills germs)
Fever is not the disease - it's body's defense mechanism!
When germs enter body:
• Immune system detects them
• Raises body temperature (fever)
• High temperature makes environment uncomfortable for germs
• Helps immune cells work better
• Kills or weakens many germs
So fever is actually helping you fight the disease! (But very high
fever needs treatment)
It's much better to prevent diseases than to treat them after getting sick. Prevention is cheaper, easier, and keeps us healthy!
Vaccination is giving a vaccine (dead or weakened germs) to a person to develop immunity against a disease. The body learns to fight that disease without actually getting sick.
Vaccination is like a fire drill in school! You practice fighting
fire (disease) without actual fire (real disease). When real fire
(disease) comes, you know exactly how to fight it!
Vaccine shows your immune system a "wanted poster" of the criminal
(germ). Your immune army creates special soldiers (antibodies) to
catch that criminal. If the real criminal attacks later, your army
recognizes and defeats it immediately!
• BCG: Tuberculosis
• DPT: Diphtheria, Pertussis (whooping cough),
Tetanus
• MMR: Measles, Mumps, Rubella
• Polio vaccine: Poliomyelitis
• Hepatitis B: Hepatitis B
• COVID-19: Coronavirus disease
• HPV: Human Papillomavirus (prevents cervical
cancer)
1. Reduce symptoms: Make patient feel better
(fever medicines, pain killers)
2. Kill the cause: Remove the disease cause
(antibiotics for bacteria, antivirals for some viruses)
Antibiotics are medicines that kill or stop the growth of bacteria. They work only against bacterial infections, NOT viral infections.
✓ Work only against bacteria (NOT viruses!)
✓ Must complete full course as prescribed
✓ Don't take antibiotics for common cold (it's viral!)
✓ Don't share or reuse old antibiotics
✓ Overuse creates antibiotic-resistant bacteria
✓ Always take as per doctor's prescription
Bacteria and viruses are very different:
• Bacteria have cell wall - antibiotics attack this wall
• Viruses have no cell wall, they hide inside our cells
• Antibiotics cannot enter our cells to kill viruses
• Our immune system must fight viruses
• Some antiviral medicines help immune system
Q1. Why is antibiotics not effective against
common cold?
Answer: Because common cold is caused by viruses,
and antibiotics work only against bacteria, not viruses.
Q2. How does vaccination provide immunity?
Answer: Vaccine contains dead/weakened germs.
Body produces antibodies against them and memory cells remember
the germ. If real germ attacks later, body fights it quickly,
preventing disease.
Q3. Distinguish between acute and chronic
diseases.
Answer: Acute diseases last for short time and
recover quickly (cold, fever). Chronic diseases last long and take
long to recover (diabetes, tuberculosis).
Your body is like a fortress with multiple security systems:
• Walls (Skin): First barrier
• Guards (WBCs): Patrol and fight invaders
• Intelligence (Antibodies): Identify and
remember enemies
• Alarm (Fever/Inflammation): Alert system when
invaded
• Training (Vaccination): Prepare guards for
future attacks
Keep your fortress strong with good food, exercise, and hygiene!