Disease

Definition

A disease is a condition that impairs normal tissue function, often caused by pathogenic microbes such as bacteria, viruses, fungi, or parasites. It can result in clinical symptoms and signs of illness.

5 Must Know Facts For Your Next Test

1. Pathogenicity refers to the ability of a microbe to cause disease in a host organism.
2. Virulence factors are molecules produced by pathogens that contribute to the pathogenicity and promote infection.
3. The incubation period is the time between exposure to a pathogen and the appearance of symptoms.
4. Diseases can be transmitted through various routes including direct contact, inhalation, ingestion, or vector-borne methods.
5. An infectious dose is the number of microbial cells required to start an infection in a host.

Review Questions

• What is pathogenicity and how does it relate to disease?
• Name at least two virulence factors produced by pathogens.
• Describe the significance of the incubation period in infectious diseases.

Related terms

Pathogen: A microorganism that can cause disease.

Virulence Factor: Molecules produced by pathogens that enhance their ability to cause disease.

Incubation Period: The time interval between exposure to an infectious agent and the onset of symptoms.