Microorganisms, Pathogens, and Human Health - Revision Sheet

1. 📌 Essentials

• Pathogens are microorganisms that cause disease in hosts.
• Louis Pasteur demonstrated causality via cultivation and inoculation.
• Major pathogens include bacteria like Bacillus anthracis and Erysipelothrix rhopathiae.
• Disease transmission occurs through contact, vectors, or contaminated sources.
• Microbiota are microorganisms colonizing body sites, essential for health.
• Dysbiosis (microbiota imbalance) links to obesity and other diseases.
• Vaccines, hygiene, and insecticides are key preventive measures.
• Antibiotics and antivirals are primary curative treatments.
• Vectors like mosquitoes transmit diseases such as malaria and chikungunya.
• Microbiota develop from birth, influenced by diet, environment, and age.

2. 🧩 Key Structures & Components

• Pathogens — microorganisms causing disease (bacteria, viruses, fungi).
• Vectors — organisms like mosquitoes that transmit pathogens.
• Microbiota — microorganisms residing in gut, skin, mouth.
• Host — organism harboring pathogens or microbiota.
• Inoculation sites — skin, mucous membranes, bloodstream.
• Reservoirs — environmental or animal sources of pathogens.
• Immune system — defends against pathogens and maintains microbiota balance.
• Transmission routes — contact, vectors, water, food.

---