state that infectious diseases are caused by pathogens and are transmissible

What are Infectious Diseases?

Infectious diseases are illnesses caused by pathogens—tiny invaders such as bacteria, viruses, fungi, or parasites. Think of them as micro‑soldiers that sneak into our bodies and cause trouble. 🦠

They are transmissible, meaning they can move from one person to another, just like a game of hot potato where the pathogen is the potato. 🔄

Common Pathogens & Diseases

• 🦠 Bacteria – e.g., Streptococcus pyogenes causes strep throat.
• 🦠 Viruses – e.g., Influenza virus causes the flu.
• 🦠 Fungi – e.g., Candida albicans causes thrush.
• 🦠 Parasites – e.g., Plasmodium falciparum causes malaria.

Transmission Routes

1. Direct contact – touching or kissing.
2. Indirect contact – touching contaminated surfaces.
3. Droplet spread – coughing or sneezing.
4. Airborne spread – tiny particles that stay in the air.
5. Vector‑borne – insects like mosquitoes.

Exam Tip Box

When answering questions about infectious diseases, keep these points in mind:

1. Define pathogen and give at least two examples.
2. Explain why diseases are transmissible and describe at least two transmission routes.
3. Use the LaTeX notation for any equations, e.g., $P = \text{pathogen}$.
4. Include an analogy or real‑world example to show understanding.
5. Remember to label diagrams clearly if you draw them.