Human Diseases: Communicable and Non-Communicable Diseases, Causes, Vectors and Vaccines for SSC General Science
Rahul Kumar
SSC Exam Expert & Content Editor
In this note
- 1.Communicable and Non-Communicable Diseases
- 2.Bacterial Diseases
- 3.Viral Diseases
- 4.Protozoan Diseases
- 5.Fungal and Worm Diseases
- 6.Vaccines and Immunisation
- 7.Non-Communicable Diseases
- 8.Tricks to Remember
- 9.Quick Tips
- 10.Quick Revision Points
- 11.Practice Questions With Answers
- 12.How to Practise This Chapter
- 13.Frequently Asked Questions
PDF Notes: Human Diseases: Communicable and Non-Communicable Diseases, Causes, Vectors and Vaccines for SSC General Science
Premium PDF · one-time payment of ₹5 · instant access
Diseases, their causative organisms and vaccines form a high-frequency topic in SSC general science. Questions typically ask which disease is caused by which organism, which vector spreads it, or which vaccine prevents it. This guide on human diseases for SSC gives all of this in tables, with the non-communicable diseases and practice questions.
Communicable and Non-Communicable Diseases
| Type | Meaning | Examples |
|---|---|---|
| Communicable (infectious) | Spread from one person to another by germs | Cholera, TB, malaria, AIDS |
| Non-communicable | Do not spread; caused by lifestyle, genes or ageing | Diabetes, cancer, hypertension, heart disease |
Bacterial Diseases
| Disease | Causative Organism | Remarks |
|---|---|---|
| Cholera | Vibrio cholerae | Spread by contaminated water; severe diarrhoea |
| Typhoid | Salmonella typhi | Water and food; Widal test |
| Tuberculosis (TB) | Mycobacterium tuberculosis | Lungs; BCG vaccine |
| Tetanus | Clostridium tetani | Through wounds; DPT vaccine |
| Diphtheria | Corynebacterium diphtheriae | Throat; DPT vaccine |
| Whooping cough (pertussis) | Bordetella pertussis | DPT vaccine |
| Plague | Yersinia pestis | Rat flea |
| Leprosy | Mycobacterium leprae | Skin and nerves; also called Hansen’s disease |
| Pneumonia | Streptococcus pneumoniae | Lungs |
| Anthrax | Bacillus anthracis | Animals; skin and lungs |
| Syphilis, gonorrhoea | Treponema pallidum, Neisseria gonorrhoeae | Sexually transmitted |
Viral Diseases
| Disease | Remarks |
|---|---|
| Polio | Poliovirus; OPV and IPV vaccines; India declared polio-free in 2014 |
| AIDS | HIV; attacks the T-helper (CD4) cells; spread by blood, sexual contact and mother to child; ELISA test |
| Hepatitis A, B, C | Liver disease; Hepatitis B vaccine |
| Dengue | Aedes mosquito; low platelet count |
| Chikungunya | Aedes mosquito |
| Rabies | Dog or animal bite; vaccine by Louis Pasteur |
| Measles, mumps, rubella | MMR vaccine |
| Chickenpox | Varicella zoster virus |
| Smallpox | Eradicated in 1980; vaccine by Edward Jenner |
| Influenza (flu) | Spread by droplets |
| COVID-19 | SARS-CoV-2; pandemic from 2020 |
Protozoan Diseases
| Disease | Causative Protozoan | Vector |
|---|---|---|
| Malaria | Plasmodium | Female Anopheles mosquito |
| Kala-azar | Leishmania donovani | Sandfly |
| Sleeping sickness | Trypanosoma | Tsetse fly |
| Amoebic dysentery | Entamoeba histolytica | Contaminated food and water |
| Giardiasis | Giardia | Contaminated water |
Fungal and Worm Diseases
| Disease | Cause | Remarks |
|---|---|---|
| Ringworm | Fungus (Trichophyton) | Skin infection |
| Athlete’s foot | Fungus | Skin of feet |
| Filariasis (elephantiasis) | Wuchereria bancrofti (worm) | Culex mosquito |
| Ascariasis | Ascaris (roundworm) | Intestine |
| Taeniasis | Tapeworm | Undercooked pork or beef |
Vaccines and Immunisation
| Vaccine | Protects Against |
|---|---|
| BCG | Tuberculosis |
| DPT | Diphtheria, pertussis and tetanus |
| OPV / IPV | Polio |
| MMR | Measles, mumps, rubella |
| Hepatitis B | Hepatitis B |
| Rotavirus vaccine | Diarrhoea in infants |
- The Mission Indradhanush was launched in 2014 for the full immunisation of children.
- Edward Jenner developed the first vaccine (smallpox) in 1796.
- Louis Pasteur developed vaccines for rabies and anthrax.
- Jonas Salk developed the injectable polio vaccine (1955) and Albert Sabin the oral polio vaccine.
Non-Communicable Diseases
| Disease | Details |
|---|---|
| Diabetes mellitus | Lack of insulin or its action; high blood sugar |
| Cancer | Uncontrolled cell division; carcinoma, sarcoma, leukaemia |
| Hypertension | High blood pressure; normal is 120/80 mm Hg |
| Goitre | Iodine deficiency; enlarged thyroid |
| Scurvy, rickets, beriberi | Deficiency of vitamins C, D and B1 |
| Night blindness | Vitamin A deficiency |
| Anaemia | Lack of iron or haemoglobin |
| Heart attack | Blockage of coronary arteries |
| Colour blindness, haemophilia | Genetic disorders |
Tricks to Remember
- Malaria is caused by Plasmodium and spread by the female Anopheles mosquito.
- Dengue and chikungunya both spread by Aedes; filaria by Culex.
- Diseases of the DPT vaccine: diphtheria, pertussis and tetanus.
- Polio, AIDS, dengue, rabies and measles are viral; cholera, typhoid and TB are bacterial; malaria is protozoan.
Quick Tips
- Group diseases by cause: bacteria, virus, protozoa and fungi.
- Learn the vectors with the diseases.
- Memorise the vaccine for each disease.
- Remember that antibiotics do not work against viruses.
Quick Revision Points
- Malaria: Plasmodium, female Anopheles.
- Cholera: Vibrio cholerae; typhoid: Salmonella typhi; TB: Mycobacterium.
- Dengue: Aedes; filaria: Culex; kala-azar: sandfly.
- BCG for TB; DPT for diphtheria, pertussis and tetanus.
- AIDS is caused by HIV.
Practice Questions With Answers
- Which organism causes malaria?
Answer: Plasmodium - Which mosquito spreads dengue?
Answer: Aedes - Which vaccine protects against TB?
Answer: BCG - What is the full form of HIV?
Answer: Human Immunodeficiency Virus - Which disease is caused by Vibrio cholerae?
Answer: Cholera - Which vector spreads kala-azar?
Answer: Sandfly - Which disease is spread by the tsetse fly?
Answer: Sleeping sickness - Which vaccine protects against diphtheria, pertussis and tetanus?
Answer: DPT - Which disease is caused by iodine deficiency?
Answer: Goitre - Which year was smallpox declared eradicated?
Answer: 1980
How to Practise This Chapter
Practise 10 questions every day and write the steps on paper. Then attempt timed sets from our practice papers and the previous year papers page. See all topics on the General Science notes page, read the previous topic Cell Biology and Genetics and the next topic Chemical Reactions, Metals and Non-Metals.
Frequently Asked Questions
What are communicable diseases?
Diseases that spread from an infected person to others through germs.
What causes malaria?
The protozoan Plasmodium, spread by the female Anopheles mosquito.
What causes cholera?
The bacterium Vibrio cholerae.
What causes tuberculosis?
The bacterium Mycobacterium tuberculosis.
Which diseases are spread by Aedes mosquito?
Dengue, chikungunya and yellow fever.
What does AIDS stand for?
Acquired Immuno Deficiency Syndrome.
What is the BCG vaccine for?
It protects against tuberculosis.
What is the DPT vaccine?
It protects against diphtheria, pertussis (whooping cough) and tetanus.
What is a vector?
An organism that carries a disease-causing agent from one host to another.
Which disease was eradicated worldwide?
Smallpox, in 1980.
What are non-communicable diseases?
Diseases that do not spread from person to person, such as diabetes and cancer.
Is this topic asked in SSC?
Yes. Diseases, vectors and vaccines are asked every year.
Previous chapter
Cell Biology and Genetics: Cell Organelles, Cell Division, Mendel's Laws, DNA and Genetic Disorders for SSC
Next chapter
Chemical Reactions, Metals and Non-Metals: Reactivity Series, Alloys, Ores and Carbon Compounds for SSC General Science
Rahul Kumar
SSC Exam Expert & Content Editor
Rahul is a senior SSC exam strategist with 8+ years of experience helping aspirants crack CGL, CHSL and MTS exams. He writes in-depth notification breakdowns, exam pattern guides and preparation strategies.