Overview
This lecture covers the basic types of pathogens, examples of diseases they cause, how they spread (transmission methods), and distinguishes communicable from non-communicable diseases.
Types of Pathogens
- Pathogens are microorganisms that cause disease, including viruses, bacteria, fungi, and protists.
- Viruses cause diseases like HIV/AIDS in animals and tobacco mosaic virus in plants.
- Bacteria cause diseases like salmonella in animals and agrobacterium in plants.
- Fungi cause diseases like athlete’s foot in animals and rose black spot in plants.
- Protists cause diseases like malaria in animals and downy mildew in plants.
Pathogen Life Cycles and Adaptations
- All pathogens infect a host, reproduce or replicate, and spread to new hosts.
- Pathogens have structural adaptations that help them complete their life cycles and cause disease.
Communicable vs. Non-Communicable Diseases
- Communicable diseases are caused by pathogens and can be transmitted between organisms.
- Non-communicable diseases include inherited disorders (e.g., cystic fibrosis), deficiency diseases (e.g., scurvy), and diseases from carcinogens (e.g., cancer).
Transmission of Pathogens
- Direct contact: Includes sexual (intercourse) and non-sexual (shaking hands) contact.
- Water: Dirty water can spread diseases like cholera.
- Air: Sneezing spreads viruses as droplets, like the common cold.
- Unhygienic food preparation: Undercooked or reheated food can spread bacteria such as E. coli.
- Vectors: Organisms that spread disease, like badgers potentially spreading tuberculosis to cattle.
Key Terms & Definitions
- Pathogen — A microorganism that causes disease.
- Communicable disease — A disease caused by a pathogen and transmitted between organisms.
- Host — The organism that a pathogen infects.
- Vector — An organism that spreads disease between hosts.
- Adaptation — A structural feature that helps an organism survive.
- Deficiency disease — Illness from a lack of essential vitamins or minerals.
- Carcinogen — A chemical or agent that causes cancer.
Action Items / Next Steps
- Review examples of each pathogen and the diseases they cause.
- Learn different ways diseases are transmitted.
- Prepare to study specific diseases caused by viruses, bacteria, fungi, and protists in detail.