Diseases and First Aid
1. What is a Disease?
A disease is any CONDITION that INTERFERES with the normal functioning of the body.
Health: A state of COMPLETE physical, mental, and social WELL-BEING (WHO definition).
'Being healthy is NOT just about not being sick — it is about being WELL in body, mind, and social interactions.'
2. Types of Diseases
Communicable (Infectious) Diseases
Spread from ONE person to ANOTHER through various modes.
| Mode of Transmission | Examples |
|---|---|
| Airborne | Common cold, influenza, tuberculosis (TB), chicken pox, COVID-19 |
| Waterborne / Foodborne | Cholera, typhoid, hepatitis A, diarrhoea |
| Vector-borne | Malaria (mosquito), dengue (mosquito), plague (rat flea) |
| Contact (direct/indirect) | Ringworm, scabies, conjunctivitis, HIV |
| Blood-borne | Hepatitis B, HIV/AIDS |
Non-Communicable (Non-Infectious) Diseases
CANNOT be transmitted from one person to another.
| Type | Cause | Examples |
|---|---|---|
| Deficiency diseases | Lack of nutrients | Anaemia (iron), scurvy (Vit C), rickets (Vit D) |
| Lifestyle diseases | Poor diet, lack of exercise, stress | Diabetes, hypertension, obesity, heart disease |
| Hereditary diseases | Genetic defects | Haemophilia, colour blindness |
| Allergies | Immune response to ALLERGENS | Asthma, hay fever, skin rashes |
| Degenerative diseases | Age-related WEAR and TEAR | Arthritis, cataract |
| Cancer | Uncontrolled CELL DIVISION | Lung cancer, breast cancer |
3. Common Infectious Diseases
| Disease | Pathogen | Symptoms | Prevention |
|---|---|---|---|
| Tuberculosis (TB) | Bacterium (Mycobacterium tuberculosis) | Cough, fever, weight loss, night sweats | BCG vaccine, avoid close contact |
| Cholera | Bacterium (Vibrio cholerae) | Severe DIARRHOEA, dehydration | Clean water, hygiene |
| Malaria | Protozoan (Plasmodium) — spread by Anopheles mosquito | FEVER, chills, sweating | Mosquito nets, repellents |
| Dengue | Virus — spread by Aedes mosquito | High fever, joint pain, rashes | Mosquito control |
| Chicken pox | Virus (Varicella zoster) | Blisters, FEVER, itching | Vaccination |
| Common cold | Virus (Rhinovirus) | Sneezing, cough, runny nose | Hand hygiene |
4. Disease Transmission Cycle
Pathogen → Source (infected person/animal) → Mode of transmission → Susceptible host → New infection
'Breaking ANY link in this chain PREVENTS the spread of disease. That is why quarantine, hygiene, and vaccination work.'
5. Prevention and Vaccination
General Prevention
| Method | What it Does |
|---|---|
| HAND washing | Removes pathogens BEFORE they enter the body |
| Safe water and food | Prevents WATERBORNE diseases |
| Mosquito control | Prevents VECTOR-BORNE diseases |
| ISOLATION / quarantine | Prevents AIRBORNE and CONTACT spread |
| VENTILATION | Reduces airborne pathogen concentration |
Vaccination
A vaccine introduces WEAKENED or DEAD pathogens (or their parts) into the body.
'Vaccination TRICKS the immune system into producing ANTIBODIES and MEMORY CELLS — so when the real pathogen attacks, the body is READY.'
Important Vaccines (India's Immunisation Programme):
- BCG: Tuberculosis (at birth)
- Polio (OPV/IPV): Poliomyelitis
- DPT: Diphtheria, Pertussis, Tetanus
- MMR: Measles, Mumps, Rubella
- Hepatitis B vaccine
- COVID-19 vaccines
6. First Aid Basics
First aid is the IMMEDIATE, temporary care given to an injured or ill person BEFORE professional medical help arrives.
| Situation | First Aid |
|---|---|
| Cuts and Scrapes | Clean wound with WATER. Apply antiseptic. COVER with sterile bandage |
| Burns (Minor) | COOL the area under running water for 10 minutes. Do NOT apply butter/cream. Cover with DRY sterile dressing |
| Fractures | Do NOT move the injured part. IMMOBILISE with a SPLINT. Seek medical help |
| Nosebleed | Sit upright. PINCH the nose for 10 minutes. Lean FORWARD (not backward) |
| Snakebite | Keep the person CALM and STILL. Do NOT cut the wound or suck venom. Take to hospital IMMEDIATELY |
| Insect Stings | Remove the STINGER (scrape, do not pinch). Apply COLD compress |
| Choking | HEIMLICH manoeuvre: abdominal thrusts to dislodge the object |
| Fainting | Lay the person FLAT. Raise LEGS. Loosen tight clothing |
Common Mistakes and Fixes
| Mistake | Fix |
|---|---|
| 'All bacteria cause disease' | MANY bacteria are BENEFICIAL (gut bacteria, nitrogen-fixing bacteria). Only PATHOGENIC bacteria cause disease |
| 'Antibiotics work against viruses' | Antibiotics kill BACTERIA. They do NOT work against VIRUSES (common cold, flu, COVID-19) |
| 'Apply butter/ice directly to a burn' | Butter TRAPS heat. Ice DAMAGES tissue. Use COOL RUNNING water for 10 minutes |
| 'Lean backward during a nosebleed' | Leaning BACKWARD causes blood to FLOW into the throat → choking. Lean FORWARD |
ICSE Exam Focus (6–8 marks)
- 2-mark questions: Define disease, pathogen, vaccine
- 3-mark questions: Distinguish communicable and non-communicable diseases
- 4-mark questions: Mode of transmission of diseases with examples
- 6-mark questions: First aid for burns/fractures or vaccination importance
Self-Test
Q1. What is the difference between communicable and non-communicable diseases? A1. Communicable diseases SPREAD from person to person (e.g., cold, cholera). Non-communicable diseases do NOT spread (e.g., diabetes, cancer).
Q2. Name the pathogen that causes malaria and how it is transmitted. A2. PATHOGEN: Plasmodium (protozoan). TRANSMISSION: Bite of infected FEMALE Anopheles mosquito.
Q3. How does vaccination protect against disease? A3. Vaccination introduces WEAKENED or inactive pathogens. The immune system produces ANTIBODIES and MEMORY CELLS. On REAL infection, the body recognises and destroys the pathogen RAPIDLY.
Q4. What first aid would you give for a minor burn? A4. (1) COOL the area under running water for 10 minutes. (2) Do NOT apply butter, ice, or cream. (3) Cover with a DRY sterile dressing. (4) Seek medical help if serious.
Q5. List three ways to prevent the spread of airborne diseases. A5. (1) Cover mouth and nose while coughing/sneezing. (2) Wear masks. (3) Maintain DISTANCE from infected persons. (4) Ensure GOOD ventilation.
Q6. Why do antibiotics not work against viruses? A6. Antibiotics target BACTERIAL structures/processes (cell wall synthesis, protein synthesis). Viruses have DIFFERENT structures and use the HOST cell's machinery — antibiotics have NO target in viruses.
