Pathogens Can Become Diseases That Infect Humans
- Before the discovery of pathogens, people believed illnesses were caused by "bad air" or curses.
- Today, we know that many diseases are caused by microorganisms that invade our bodies.
- A broad range of disease-causing organisms can infect humans.
Definition
Disease
A disease is a disruption to the normal function or structure of the body, often caused by harmful microorganisms.
What is a Pathogen?
Definition
Pathogen
Pathogen refers to any organism or agent capable of causing disease.
- A pathogen is a microorganism that causes disease.
- These tiny invaders can be bacteria, viruses, fungi, protists, or even abnormal proteins called prions.
- Pathogens are responsible for a wide range of illnesses, from the common cold to life-threatening diseases like Ebola.
Archaea, another group of microorganisms, are not known to cause diseases in humans.
Types of Pathogens
1. Bacteria
- Bacteria are single-celled organisms that can survive in various environments.
- While many bacteria are harmless or even beneficial, some are pathogenic.
- Tuberculosis, cholera, and strep throat are examples of bacterial infections.
2. Viruses
- Viruses are made of genetic material (either DNA or RNA) surrounded by a protein coat.
- They cannot reproduce on their own, instead, they hijack a host cell's machinery to replicate.
- Viruses are responsible for a wide range of diseases, such as the flu, HIV/AIDS, and the common cold.
Prions are unique because they are not living organisms, yet they can still cause disease.
3. Fungi
- Fungi can be unicellular (e.g., yeast) or multicellular (e.g., molds).
- Fungi are responsible for infections like athlete's foot, ringworm, and thrush.
4. Protists
- Structure: Protists are single-celled organisms that can be either free-living or parasitic.
- Diseases Caused: Malaria, caused by the parasite Plasmodium, is one of the most well-known protist diseases.
