Health and Hygiene

• WHO Definition of Health: "Health is a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity."
• Difference between Disease-Free and Healthy:
1. Being Disease-Free is a purely physical state where no pathological infection or organ dysfunction is detected by clinical tests.
2. Being Healthy encompasses psychological stability, emotional resilience, absence of mental depression, and positive harmonious social relationships.
3. A person may test free from biological infections, yet suffer from severe clinical anxiety or social isolation, rendering them unhealthy under the holistic WHO criteria.

• Kwashiorkor:
• Cause: Deficiency of dietary proteins only, while calorie intake may be adequate.
• Age Group: Typically affects toddlers aged $1\text{ to } 5\text{ years}$ when displaced from breast milk.
• Symptoms: Edema (swelling of feet and legs due to fluid retention), a protruding pot-belly, dark scaly skin patches, and thinning reddish-brown hair.
• Marasmus:
• Cause: Severe deficiency of both proteins and total calories (carbohydrates and fats).
• Age Group: Usually affects young infants under $1\text{ year}$ of age.
• Symptoms: No edema; severe emaciation with wasting of all muscle and subcutaneous fat; ribs clearly visible through skin; wrinkled shriveled "old man" face.

• (a) Vitamin A deficiency: Night Blindness (Nyctalopia) and Xerophthalmia.
• (b) Vitamin C deficiency: Scurvy (bleeding swollen gums, loose teeth, fragile capillaries).
• (c) Vitamin D deficiency: Rickets in children (soft, malformed leg bones, bow legs) and Osteomalacia in adults.
• (d) Iodine deficiency: Simple Goitre (abnormal enlargement of the thyroid gland in the neck).
• (e) Iron deficiency: Anemia (low hemoglobin count, fatigue, pallor, reduced oxygen-carrying capacity).

• (a) Tuberculosis:
• Pathogen: Bacterium Mycobacterium tuberculosis.
• Transmission: Airborne droplet infection from coughing and sneezing of an infected patient.
• Vaccine: BCG Vaccine (Bacillus Calmette-Guérin).
• (b) Cholera:
• Pathogen: Bacterium Vibrio cholerae.
• Transmission: Ingestion of water and food contaminated with faeces; houseflies.
• Prevention: Oral Cholera Vaccine, clean boiled water, and immediate ORS rehydration.
• (c) Malaria:
• Pathogen: Protozoan parasite Plasmodium vivax.
• Transmission: Vector-borne via the bite of an infected female Anopheles mosquito.
• Prevention: Anti-malarial drugs (chloroquine), mosquito nets, eliminating stagnant water breeding sites.

• Definition: A Vaccine is a dead, weakened (attenuated) pathogen, or harmless viral/bacterial antigen that is introduced into the body to stimulate immunity without causing illness.
• Mechanism of Protection:
1. When injected, the harmless antigens trigger white blood cells (B-lymphocytes) to produce specific protective proteins called Antibodies.
2. Crucially, the immune system creates Memory B and T cells that remain in circulation for decades.
3. If the genuine, virulent pathogen attacks the body in the future, these memory cells recognize it instantly and mount a massive, overwhelming antibody attack that neutralizes the infection before it can cause disease.

• Innate (Natural) Immunity: The non-specific defense mechanisms that are present from birth and inherited from parents. It acts as an immediate physical, chemical, and cellular barrier against all invaders.
Examples: Unbroken skin, hydrochloric acid in stomach, lysozyme enzyme in tears and saliva, phagocytic white blood cells.
• Acquired (Adaptive) Immunity: The pathogen-specific resistance that an individual develops during their lifetime following natural exposure to an infection or through artificial vaccination, mediated by specific antibodies and memory cells.

• (a) BCG: Bacillus Calmette-Guérin (vaccine against Tuberculosis).
• (b) DPT: Diphtheria, Pertussis (Whooping Cough), Tetanus (triple vaccine).
• (c) WHO: World Health Organization.
• (d) ORS: Oral Rehydration Salts (electrolyte-glucose solution to treat dehydration).

• Stagnant water serves as the ideal breeding ground for mosquitoes.
• The female Anopheles mosquito (vector for Malaria) and the female Aedes aegypti mosquito (vector for Dengue and Chikungunya) lay their eggs in open standing water.
• Eliminating stagnant water pools, emptying air coolers, and spraying kerosene/larvicidal oils breaks the mosquito reproductive life cycle, preventing devastating neighborhood epidemics of mosquito-borne diseases.