Study Notes
Communicable diseases are caused by pathogens that can spread between individuals or from animals to humans. These diseases are distinct from non-communicable diseases, which are not caused by microorganisms and cannot be transmitted between people.
- Pathogen — an organism that causes disease. Example: Viruses, bacteria, fungi, and protists are all types of pathogens.
- Virus — a type of pathogen that enters cells and replicates, causing the cell to burst. Example: Measles is a viral disease spread through droplet infection.
- Bacteria — microorganisms that multiply quickly and release toxins. Example: Salmonella causes food poisoning and is spread through contaminated food.
- Fungi — can be single-celled or have a body made of hyphae, spreading through spores. Example: Rose black spot affects plants and spreads through water or wind.
- Protists — often parasitic, using hosts to live and reproduce. Example: Malaria is caused by protists and spread by mosquitoes.
Exam Tips
Key Definitions to Remember
- Pathogen: An organism that causes disease.
- Virus: A pathogen that replicates inside cells.
- Bacteria: Microorganisms that release toxins.
Common Confusions
- Not all diseases are communicable; non-communicable diseases cannot be spread between people.
- Antibiotics are ineffective against viruses.
Typical Exam Questions
- What is a pathogen? An organism that causes disease.
- How do viruses differ from bacteria? Viruses replicate inside cells, while bacteria release toxins.
- How can the spread of malaria be prevented? Using insecticide-treated nets and removing stagnant water.
What Examiners Usually Test
- Understanding of different types of pathogens and their transmission.
- Methods of preventing the spread of communicable diseases.