Microorganisms, Diseases, and Transmission: Revision Sheet

1. 📌 Essentials

• Microorganisms include viruses, bacteria, eukaryotes, parasites, and prions.
• Pathogens are microorganisms causing disease.
• Transmission modes: direct contact, vectors, contaminated/food, airborne.
• Key diseases: Malaria (Plasmodium), Measles (morbillivirus), HIV/AIDS (VHI), Tub (Mycobacterium tuberculosis).
• Vaccines prevent many infectious diseases (e.g., MMR, BCG).
• Antimicrobials include antimalarials, antibiotics, antivirals.
• Vectors like mosquitoes transmit specific pathogens.
• Human microbiota plays a crucial role in health; dysbiosis linked to disease.
• Climate change impacts disease distribution and epidemiology.
• Microorganisms are invisible without microscopy.

2. 🧩 Key Structures & Components

• Pathogens — microorganisms causing disease (viruses, bacteria, eukaryotes, parasites, prions).
• Host — organism developing symptoms upon infection.
• Vector — organism or element transmitting pathogens (e.g., mosquitoes, contaminated objects).
• Microbiota — beneficial microorganisms residing in humans, aiding health.
• Transmission routes — direct contact, vectors, airborne, contaminated water/food.
• Vaccines — biological preparations providing immunity (e.g., MMR, BCG).
• Antimicrobials — drugs targeting pathogens (e.g., chloroquine, antibiotics, antiretrovirals).

3. 🔬 Functions, Mechanisms & Relationships