Diseases Affecting Human Beings
Human beings can suffer from acquired or congenital diseases. Congenital diseases are those defects or disorders present from birth and resulting from errors in metabolism or defective body development. Acquired diseases may be —
(1) Deficiency diseases,
(2) Infectious or communicable diseases,
(3) Degenerative diseases,
(4) Allergies,
(5) Cancers.
(1) Deficiency Diseases - Deficiency diseases are due to deficiency in the diet of a nutrient. They can generally be cured by providing the missing nutrients.
(a) Protein deficiency causes two major diseases Kwashiorkor and Marasmus.
(b) Mineral deficiency causes specific diseases :-
(i) Anaemia - Iron deficiency causes haemoglobin deficiency in blood.
(ii) Goitre - It is due to the deficiency of iodine for the synthesis of thyroxine hormone of thyroid gland.
(iii) Hypokalemia - It is caused by deficiency of potassium.
(iv) Hyponatremia - Loss of sodium causes this state of low blood pressure and loss of body weight.
(c) Vitamin deficiency causes a variety of diseases :-
(i) Night Blindness - It is caused by the deficiency of Vitamin A.
(ii) Xerophthalmia - It is the dryness of the eyes and is caused by the deficiency of Vitamin A.
(iii) Dermatosis - It is caused by the deficiency of Vitamin A.
(iv) Beri-beri - It is caused by the deficiency of Vitamin B1 (thiamine).
(v) Ariboflavinosis - It is caused by the deficiency of vitamin B2 (riboflavin).
(vi) Pellagra - It is caused by deficiency of nicotinic acid (niacin), a vitamin of the B complex.
(vii) Pernicious Anaemia - It is caused by the deficiency of Vitamin B12 (cobalamin).
(viii) Scurvy - It is caused due to the deficiency of Vitamin C or ascorbic acid.
(ix) Rickets - It is a disease causing disorder of calcium and phosphorus metabolism which is associated with the deficiency of Vitamin D, and beginning most often in infancy and early childhood between the ages of 6 months and 2 years.
(x) Osteomalacia - It occurs in adults due to deficiency of Vitamin D.
2. Infectious or Communicable Diseases : These diseases are caused by various agents such as virus, bacteria,
fungi and protozoa.
(a) Diseases caused by Bacteria are : Cholera, Diphtheria, Tuberculosis, Leprosy, Tetanus, Typhoid, Plague, Whooping Cough, Sore Throat, Pneumonia, Bacillary Dysentery, Gonorrhoea, Syphilis and Botulism.
(b) Diseases caused by Viruses are : Chickenpox, Measles, Poliomyelitis, Rabies, Mumps, Influenza, Hepatitis, Herpes, Viral Encephalitis and AIDS.
(c) Diseases caused by Fungi are : Ringworm, Athlete's foot, Dhobie itch.
(d) Diseases caused by Protozoans are: Amoebiasis, Malaria, Sleeping sickness, Kala-zar, Diarrhoea.
(e) Diseases caused by Helminthes or Worms are : Filaria, Tapeworm and Hookworm transmission.
3. Degenerative Diseases : These diseases occur due to malfunctioning of some organ or organ system in the body. They are : Heart attack, Diabetes mellitus, Arthritis.
4. Allergies : Allergy is any condition in which a person reacts in a hypersensitive manner to any substance. Symptoms mostly affect the skin and mucous membrane, may be in reaction to specific foodstuff, drugs, fabrics, dust, pollen, plants, animals, heat, cold. The major types of allergy are hay fever, asthma and eczema.
5. Cancer : Cancer is the abnormal growth of cells, often resulting in a malignant tumour. Symptoms include wounds that do not heal, unusual bleeding or discharge, a lump or thickening in the breast or elsewhere, a sore that does not heal, hoarseness or cough, change in size or colour of wart or mole, indigestion or difficulty in swallowing. They are classified according to the tissues in which they originate.
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