Human Disease
1) Human Disease
★ Any disorder or malfunction occurring in a part of the human body is called a disease. There are several types:
1. Congenital or Genetic Diseases:
These are inherited diseases passed from one generation to the next.
Examples:
- Hemophilia – Inability of blood to clot.
- Color Blindness – Inability to distinguish red and green.
- Schizophrenia (brain-related) – Talking alone, laughing, crying, sudden anger, etc.
2. Non-Infectious Diseases:
Diseases that do not spread from one person to another.
Examples: Cancer, Heart Disease, Kidney Disease.
3. Infectious or Communicable Diseases:
Diseases that spread through contact between individuals.
Examples: Smallpox, TB. These are mainly caused by protozoa, fungi, worms, bacteria, or viruses.
2) Diseases Caused by Protozoa
★ Dysentery: Caused by Entamoeba histolytica, affects the large intestine, spreads through contaminated food or water.
★ Kala-Azar (Black Fever): Caused by Leishmania, spread by sandflies, affects the spleen.
★ Malaria: Caused by Plasmodium, spread by female Anopheles mosquitoes, affects the spleen.
Note: Male Anopheles mosquitoes are harmless; they feed on nectar.
- Medicine: Chloroquine
- Derived from Quinine (from Cinchona bark), majorly found on Java Island, Indonesia.
★ Sleeping Sickness (Insomnia): Caused by Trypanosoma, spread by Tse-Tse fly, affects the nervous system.
★ Pyorrhea: Caused by Entamoeba gingivalis, found in dirty water, affects gums.
3) Diseases Caused by Fungi
Note: Fungi usually cause skin itching.
Diseases Caused by Worms (Helminths)
- Filariasis (Elephantiasis): Caused by Wuchereria bancrofti, spread by female Culex mosquito, affects the lymphatic system.
- Diarrhea: Caused by Ascaris worm, leads to intestinal ulcers. Emperor Akbar died of this.
Diseases Spread by Vectors (Insects)
| Vector | Disease |
|---|---|
| Female Anopheles mosquito | Malaria |
| Female Culex mosquito | Filariasis |
| Female Aedes mosquito | Dengue |
| Tse-Tse fly | Sleeping sickness |
| Housefly | Cholera |
| Sandfly | Kala-Azar |
4) Diseases Caused by Bacteria
★ Diphtheria: Affects the respiratory system, caused by Corynebacterium diphtheriae. Prevented by DPT vaccine (also called Triple Vaccine).
★ Plague (Black Death): Spread by rats, caused by Pasteurella pestis.
★ Syphilis & Gonorrhea: STDs, caused by Treponema and Neisseria gonorrhoeae respectively.
★ Tetanus (Lockjaw): Caused by Clostridium tetani, patient is kept in a dark room.
★ Leprosy: Affects limbs, caused by Mycobacterium leprae. Treated with MDT.
★ Typhoid: Affects intestines, caused by Salmonella typhi, also called “Enteric fever.”
★ TB (Tuberculosis): Affects lungs, caused by Mycobacterium tuberculosis, spreads through milk.
- Child vaccine = BCG
- Adult treatment = DOTS
★ Pneumonia: Lungs get blocked.
★ Cholera: Affects intestines, spreads through contaminated water/food, caused by Vibrio cholerae.
5) Diseases Caused by Viruses
★ AIDS: Destroys immune system (WBCs – T-cells), caused by HIV (Human Immunodeficiency Virus)
- First case: California, 1981
- Named in 1982
- First seen in India (Goa), 1992
- Detected via ELISA Test (Enzyme-Linked Immunosorbent Assay)
★ Dengue: “Breakbone fever”, caused by Aedes mosquito bite, lowers blood platelets.
★ Polio: Caused by Enterovirus, affects lymph and nerves.
- Oral drops: Discovered by Albert Sabin
- Injection: Discovered by Jonas Salk
- Spread through contaminated water/food
- Declared polio-free by WHO on 27 March 2014
★ Influenza (Flu): Caused by Myxovirus, affects respiratory system.
- Bird Flu (H5N1): From chickens
- Swine Flu (H1N1): From pigs
★ Smallpox: Caused by Variola virus, affects skin, vaccine by Edward Jenner, eradicated in India by 1975.
★ Mumps: Affects salivary glands
★ Measles: Affects skin and respiratory system in children
★ Trachoma: Affects eyes, leads to fleshy growth
★ Hepatitis/Jaundice: Caused by RNA virus, affects liver
★ Meningitis: Affects the brain
★ Herpes: Affects skin
★ Rabies: From dog bites, affects nervous system, discovered by Louis Pasteur
Remark: Epilepsy also affects the nervous system, triggered by water, heat, etc.
Cancer
★ Abnormal cell growth is called Cancer (Carcinoma) or Leukemia.
- Latent period: Time before symptoms appear
- Treatment: Chemotherapy, Cobalt-60 (Gamma rays), Interferon
- Study of cancer: Oncology
- Affected cells form Neoplasm or Tumor
Deficiency Diseases
Diseases caused due to lack of nutrients:
- Anemia – Iron deficiency
- Goiter – Iodine deficiency
- Kwashiorkor & Marasmus – Protein deficiency
- Night blindness, Beriberi, Scurvy, Rickets – Vitamin deficiency
Types of Medicines
Medicines strengthen WBCs and help the body fight diseases.
- Antibiotics: Kill bacteria
- Penicillin, Streptomycin, Tetracycline, Chloramphenicol
- Antiseptics: Heal wounds
- Boric acid, Dettol, Iodine, Chloramine, Phenol
- Antipyretics: Reduce fever
- Aspirin, Paracetamol, Saridon
- Analgesics: Pain relievers
- Morphine, Heroin
- Anesthetics: Induce unconsciousness (used in surgery)
- Chloroform, Ether, Local Anesthesia
Chloroform is stored in colored bottles to avoid sunlight reaction. Chemical name: Trichloromethane (CHCl₃)
Toxic Effects
Overuse of medicines can lead to toxic effects. For example, too much morphine affects breathing.
Saline
Saline is used to provide instant energy. Types:
- Dextrose (D-5, D-10): Used in general weakness and delivery but not for cough patients
- Normal Saline (N.S.): Used in dehydration, blood loss, wound cleaning, and injection dilution
Max: 3–4 bottles in 24 hours
Not given to High BP patients
