Diseases & Vitamins

Disease types:

• Infectious / communicable: caused by pathogens (virus, bacteria, fungi, parasites). Spread person-to-person.
• Non-infectious / non-communicable: lifestyle/genetic. E.g. diabetes, hypertension, cancer.
• Deficiency: due to lack of nutrient. E.g. scurvy (vitamin C), beriberi (vitamin B1).
• Hereditary: genetic. E.g. sickle-cell anaemia, haemophilia.

Common bacterial diseases:

• Tuberculosis (TB): Mycobacterium tuberculosis. Affects lungs.
• Typhoid: Salmonella typhi. From contaminated water/food. Symptoms: high fever, diarrhoea.
• Cholera: Vibrio cholerae. Severe diarrhoea, dehydration.
• Diphtheria: throat infection.
• Tetanus: Clostridium tetani. From contaminated wounds (rusty nails).
• Plague: Yersinia pestis. From rats/fleas.
• Leprosy: Mycobacterium leprae. Skin and nerves.

Common viral diseases:

• Influenza (flu): respiratory.
• Common cold: rhinovirus.
• Smallpox: eradicated globally in 1980 (last case in India in 1975).
• Polio: India declared polio-free 2014.
• Measles, mumps, rubella: prevented by MMR vaccine.
• AIDS: HIV virus; attacks immune system.
• Hepatitis A, B, C: liver inflammation.
• Dengue: Aedes mosquito; fever, joint pain ("breakbone fever").
• Chikungunya: Aedes mosquito.
• Malaria: caused by Plasmodium (a protozoan, not a virus). Anopheles mosquito vector.
• COVID-19: SARS-CoV-2; respiratory, started in Wuhan 2019.

Common fungal diseases: ringworm, athlete's foot, candidiasis.

Parasitic worms: roundworm, tapeworm, pinworm.

Vector-borne diseases (mosquito-transmitted):

• Anopheles: Malaria.
• Aedes aegypti: Dengue, Chikungunya, Zika, Yellow fever.
• Culex: Filariasis, Japanese encephalitis.

Vitamins and their deficiency diseases:

Fat-soluble vitamins: A, D, E, K. Water-soluble: B-complex, C.

Mineral deficiencies:

• Iron: anaemia (fatigue, pale skin). Sources: meat, leafy greens, jaggery.
• Calcium: weak bones/teeth, osteoporosis. Sources: milk, cheese, broccoli.
• Iodine: goitre, hypothyroidism. Source: iodized salt.
• Zinc: poor wound healing, immunity. Sources: nuts, seeds.
• Fluoride deficiency: tooth decay. Excess: fluorosis (mottled teeth).

Diabetes — three types:

• Type 1: autoimmune destruction of insulin cells. Requires insulin injection.
• Type 2: insulin resistance. Often linked to obesity. Manageable with diet + exercise + medication.
• Gestational: during pregnancy.

Cancer:

• Uncontrolled cell division.
• Benign (localized) vs malignant (spreads — metastasizes).
• Top cancers in India: oral (tobacco), breast, cervical, lung.
• Treatment: surgery, chemotherapy, radiotherapy, immunotherapy.

HIV / AIDS:

• HIV (Human Immunodeficiency Virus) destroys CD4 T-cells of immune system.
• Spread: sexual contact, sharing needles, mother-to-child.
• Treatment: antiretroviral therapy (ART) extends life dramatically.
• World AIDS Day: December 1.

Tuberculosis (TB):

• India accounts for ~26% of global TB cases.
• Spread by airborne droplets.
• Treatment: 6-month course of antibiotics (DOTS — directly observed treatment, short course).
• BCG vaccine in childhood gives partial protection.

Vaccines (Universal Immunization Programme in India):

• BCG (TB), Polio (oral and injectable), DPT (diphtheria, pertussis, tetanus), Measles, Hepatitis B, Rotavirus, Pneumococcal.

Recent outbreaks/issues:

• COVID-19 (2019–2023): pandemic; vaccines developed in record time (Covishield, Covaxin, Sputnik, Pfizer).
• Nipah virus: Kerala outbreaks in 2018, 2021, 2023, 2024. Fruit bat reservoir.
• Mpox (Monkeypox): WHO declared global emergency in 2022.

Lifestyle disease prevention:

• Balanced diet (50% carbs, 30% fat, 20% protein roughly; less sugar/salt).
• 150 min/week moderate exercise.
• No tobacco; limit alcohol.
• Adequate sleep (7–8 hrs).
• Stress management.

WHO definition of health: "A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity."

World Health Day: April 7 (WHO founding day, 1948).