UPPCS Prelims Biology: Human Diseases, Causes and Important Facts
A quick-revision guide for UPPCS / all state pcs aspirant
Human diseases are a reliable topic in UPPCS Prelims General Science. Questions are usually direct: which organism causes the disease, which vector spreads it, which deficiency leads to it, which organ is affected. Learn the tables below and you can secure 2 to 3 easy marks.
1. Classification of Diseases
Type | Meaning | Examples |
|---|---|---|
Communicable | Spread from person to person through air, water, food, contact or vectors | TB, cholera, malaria |
Non-communicable | Do not spread | Diabetes, cancer, hypertension |
Deficiency | Lack of vitamins, minerals or protein | Scurvy, goitre, kwashiorkor |
Genetic | Defect in genes or chromosomes | Haemophilia, Down syndrome |
Occupational / environmental | Caused by dust, chemicals or pollutants | Silicosis, Minamata disease |
Tip: Antibiotics work on bacteria, not viruses. Viral diseases are controlled through vaccines.
2. Bacterial Diseases
Disease | Causative organism | Key fact |
|---|---|---|
Cholera | Vibrio cholerae | Contaminated water; treated with ORS |
Typhoid | Salmonella typhi | Diagnosed by the Widal test |
Tuberculosis | Mycobacterium tuberculosis | Discovered by Robert Koch; vaccine BCG |
Diphtheria | Corynebacterium diphtheriae | Throat infection; DPT vaccine |
Whooping cough | Bordetella pertussis | DPT vaccine |
Tetanus | Clostridium tetani | Lockjaw; enters through wounds |
Leprosy | Mycobacterium leprae | Also called Hansen’s disease |
Plague | Yersinia pestis | Spread by rat fleas |
Anthrax | Bacillus anthracis | Affects cattle and humans |
Pneumonia | Streptococcus pneumoniae (commonly) | Lung infection |
Syphilis | Treponema pallidum | Sexually transmitted |
Gonorrhoea | Neisseria gonorrhoeae | Sexually transmitted |
Botulism | Clostridium botulinum | Spoiled canned food |
Trachoma | Chlamydia trachomatis | Eye infection |
Scrub typhus | Orientia tsutsugamushi | Spread by mites |
Leptospirosis | Leptospira | Water contaminated with animal urine |
3. Viral Diseases
Disease | Virus / vector | Key fact |
|---|---|---|
Polio | Poliovirus | India declared polio-free in 2014 |
Smallpox | Variola virus | Eradicated worldwide in 1980; Edward Jenner developed the vaccine |
Chickenpox | Varicella-zoster virus | Skin rash |
Measles, Mumps, Rubella | Paramyxoviruses (measles, mumps) and rubella virus | Vaccine is MMR |
Rabies | Rabies virus | Dog bite; Louis Pasteur developed the vaccine |
AIDS | HIV, a retrovirus | Attacks CD4 helper T cells; ELISA for screening, Western blot for confirmation; does not spread by touch or mosquito bites |
Dengue | Dengue virus; Aedes aegypti | Break-bone fever; platelets fall |
Chikungunya, Zika, Yellow fever | Aedes mosquito | Mosquito-borne |
Japanese encephalitis | Flavivirus; Culex | Pigs are amplifying hosts; eastern UP has had repeated outbreaks |
Hepatitis A, E | Water and food borne | Liver infection |
Hepatitis B, C, D | Blood and body fluids | Vaccine exists for Hepatitis B |
Influenza | Influenza virus | Swine flu is H1N1; bird flu is H5N1 |
COVID-19 | SARS-CoV-2 | Coronavirus |
Nipah | Nipah virus | Fruit bats are the natural host |
Kyasanur Forest Disease | Virus; ticks | Also called monkey fever |
Mpox | Monkeypox virus | Rash illness |
4. Protozoan Diseases
Disease | Organism | Vector / source | Key fact |
|---|---|---|---|
Malaria | Plasmodium | Female Anopheles | P. falciparum is most dangerous; Ronald Ross showed the mosquito’s role, Laveran discovered the parasite |
Amoebiasis | Entamoeba histolytica | Contaminated food and water | Amoebic dysentery |
Kala-azar | Leishmania donovani | Sandfly | Visceral leishmaniasis |
Sleeping sickness | Trypanosoma | Tsetse fly | Affects the nervous system |
Giardiasis | Giardia lamblia | Contaminated water | Intestinal infection |
Trichomoniasis | Trichomonas vaginalis | Sexual contact | Reproductive tract infection |
5. Worm (Helminthic) Diseases
Disease | Organism | Key fact |
|---|---|---|
Filariasis (elephantiasis) | Wuchereria bancrofti | Spread by Culex; swelling of limbs |
Ascariasis | Ascaris lumbricoides | Roundworm |
Taeniasis | Taenia solium | Pork tapeworm |
Hookworm | Ancylostoma duodenale | Causes anaemia |
Pinworm | Enterobius vermicularis | Common in children |
Guinea worm | Dracunculus medinensis | Contaminated water; India certified free in 2000 |
Schistosomiasis | Schistosoma | Water snails |
6. Fungal Diseases
Disease | Organism | Key fact |
|---|---|---|
Ringworm | Trichophyton, Microsporum, Epidermophyton | Not caused by a worm |
Athlete’s foot | Fungus | Foot infection |
Candidiasis | Candida albicans | Mouth and genital infection |
Aspergillosis | Aspergillus | Lung infection |
Mucormycosis (black fungus) | Mucor, Rhizopus | Widely discussed during COVID-19 |
Histoplasmosis | Histoplasma | Lung infection |
7. Vector Quick Table
Vector | Diseases spread |
|---|---|
Anopheles | Malaria |
Aedes | Dengue, Chikungunya, Zika, Yellow fever |
Culex | Filariasis, Japanese encephalitis |
Sandfly | Kala-azar |
Tsetse fly | Sleeping sickness |
Rat flea | Plague |
Housefly | Cholera, typhoid, dysentery |
Tick | Kyasanur Forest Disease |
Mite | Scrub typhus |
Louse | Epidemic typhus |
8. Vitamin Deficiency Diseases
Vitamin | Deficiency disease |
|---|---|
A (retinol) | Night blindness, xerophthalmia |
B1 (thiamine) | Beriberi |
B2 (riboflavin) | Cracks at mouth corners, sore tongue |
B3 (niacin) | Pellagra (dermatitis, diarrhoea, dementia) |
B6 | Anaemia, convulsions |
B7 (biotin) | Skin problems, hair loss |
B9 (folic acid) | Megaloblastic anaemia, neural tube defects |
B12 | Pernicious anaemia |
C (ascorbic acid) | Scurvy |
D | Rickets (children), osteomalacia (adults) |
E | Reproductive problems, muscle weakness |
K | Delayed blood clotting |
9. Mineral and Protein Deficiency
Deficiency | Disease |
|---|---|
Iron | Anaemia |
Iodine | Goitre; in infancy, cretinism |
Calcium | Weak bones, osteoporosis |
Excess fluoride | Fluorosis |
Protein | Kwashiorkor |
Protein and calories | Marasmus |
10. Genetic Disorders
Disorder | Cause | Key fact |
|---|---|---|
Down syndrome | Trisomy 21 | 47 chromosomes |
Turner syndrome | XO | Female, 45 chromosomes |
Klinefelter syndrome | XXY | Male, 47 chromosomes |
Patau syndrome | Trisomy 13 | Severe disorder |
Edwards syndrome | Trisomy 18 | Severe disorder |
Cri-du-chat | Deletion in chromosome 5 | Cat-like cry in infants |
Haemophilia | X-linked recessive | “Royal disease” (Queen Victoria’s descendants); blood does not clot |
Colour blindness | X-linked recessive | More common in males |
Sickle cell anaemia | Autosomal recessive | Abnormal haemoglobin (HbS) |
Thalassemia | Defective haemoglobin production | Inherited |
Phenylketonuria | Enzyme defect | Cannot process phenylalanine |
Albinism | Lack of melanin | Inherited |
11. Hormonal Disorders
Disorder | Cause |
|---|---|
Diabetes mellitus | Insulin deficiency or resistance (pancreas, islets of Langerhans) |
Diabetes insipidus | Deficiency of ADH (vasopressin) |
Goitre | Enlarged thyroid, often from iodine deficiency |
Graves’ disease | Excess thyroid hormone; protruding eyes |
Myxoedema | Low thyroid hormone in adults |
Addison’s disease | Low adrenal cortex hormones |
Cushing’s syndrome | Excess cortisol |
Gigantism | Excess growth hormone in childhood |
Acromegaly | Excess growth hormone in adults |
Dwarfism | Low growth hormone in childhood |
Tetany | Low calcium due to low parathyroid hormone |
12. Non-Communicable and Lifestyle Diseases
Disease | Key fact |
|---|---|
Cancer | Uncontrolled cell division; leukaemia is blood cancer |
Hypertension | High blood pressure (normal about 120/80 mm Hg) |
Jaundice | Excess bilirubin; linked to the liver |
Cirrhosis | Liver scarring, often from alcohol |
Gout | Uric acid crystals in joints |
Osteoporosis | Loss of bone density |
Asthma | Allergic narrowing of airways |
Cataract | Clouding of the eye lens |
Glaucoma | Raised eye pressure |
Parkinson’s disease | Low dopamine |
Alzheimer’s disease | Progressive memory loss |
Epilepsy | Seizures from abnormal brain activity |
Eye defects and correction:
Defect | Correction |
|---|---|
Myopia (short-sightedness) | Concave lens |
Hypermetropia (long-sightedness) | Convex lens |
Presbyopia (age-related) | Bifocal lens |
Astigmatism | Cylindrical lens |
13. Occupational and Environmental Diseases
Disease | Cause |
|---|---|
Silicosis | Silica dust |
Asbestosis | Asbestos |
Black lung (pneumoconiosis) | Coal dust |
Byssinosis | Cotton dust |
Minamata disease | Mercury |
Itai-itai disease | Cadmium |
Blue baby syndrome | Nitrates in water |
14. Vaccines and Discoveries
Vaccine | Protects against |
|---|---|
BCG | Tuberculosis |
DPT | Diphtheria, Pertussis, Tetanus |
MMR | Measles, Mumps, Rubella |
OPV / IPV | Polio |
Scientist | Contribution |
|---|---|
Edward Jenner | Smallpox vaccine |
Louis Pasteur | Rabies vaccine, germ theory |
Robert Koch | TB and cholera bacteria |
Alexander Fleming | Penicillin (1928) |
Ronald Ross | Malaria transmission |
Mission Indradhanush is India’s child and maternal immunisation drive. Check programme names and statistics against the latest government updates before the exam.
15. Practice Questions
Tuberculosis is caused by: (a) Vibrio cholerae (b) Mycobacterium tuberculosis (c) Salmonella typhi (d) Clostridium tetani
Dengue is spread by: (a) Anopheles (b) Culex (c) Aedes (d) Tsetse fly
Pellagra is due to deficiency of: (a) B1 (b) B3 (c) C (d) D
Down syndrome is caused by: (a) Monosomy X (b) Trisomy 21 (c) Trisomy 18 (d) XXY
The “royal disease” is: (a) Colour blindness (b) Haemophilia (c) Thalassemia (d) Albinism
Kala-azar is spread by: (a) Sandfly (b) Tsetse fly (c) Tick (d) Housefly
HIV mainly attacks: (a) RBCs (b) Platelets (c) CD4 helper T cells (d) Neurons
Minamata disease is due to: (a) Lead (b) Cadmium (c) Mercury (d) Arsenic
Answers: 1-b, 2-c, 3-b, 4-b, 5-b, 6-a, 7-c, 8-c
16. Preparation Tips
Learn diseases by category first (bacterial, viral, protozoan), then by vector, then by deficiency.
Watch for trick questions. Ringworm is fungal, malaria is protozoan, and typhoid is bacterial.
Make your own one-page table with Disease, Cause, Vector or source, and Key fact.
Link with current affairs, since outbreaks and health campaigns often appear.
Solve the last 10 years of UPPSC General Studies papers.
from CSMP IAS
Focus on the causative agent, the vector, the affected organ and the preventive measure. With two or three quick revisions, you can answer almost every question from this section.
All the best for your UPPCS Prelims preparation!
