Pathogen

Definition

A pathogen is a microorganism that causes disease in its host. Pathogens can be bacteria, viruses, fungi, or parasites.

5 Must Know Facts For Your Next Test

1. Pathogens are capable of causing diseases by bypassing the immune system.
2. Bacteria and viruses are the most common types of pathogens studied in microbiology.
3. Some pathogens are opportunistic, meaning they cause disease primarily when the host's defenses are compromised.
4. Pathogenicity refers to the ability of a pathogen to cause disease, while virulence is the degree of damage caused by the pathogen.
5. Vaccines and antibiotics are critical tools for preventing and treating infections caused by pathogens.

Review Questions

• What are the four main types of pathogens?
• How do pathogens bypass the immune system to cause disease?
• What is the difference between pathogenicity and virulence?

Related terms

Microorganism: A microscopic organism such as bacteria, virus, or fungus.

Host: An organism that harbors a pathogen, providing nutrients and shelter.

Antibiotic: A substance used to kill or inhibit the growth of bacteria.