Virulence - (qualitative or quantitative term)

• ability/capacity of a microorganism to cause disease

• Virulence factor - bacterial product or strategy that contributes to the organism's ability to survive in the host or cause damage to the host

Pathogenesis - (qualitative term) - Process by which microbes cause disease in a host. Follows virulence, determined by virulence factors

LD50 - A term used to assess the virulence of a pathogen and develop intervention strategies in pathogenesis. Represents the amount of a microbe that can cause death in exactly half of the exposed animals (be familiar with graph)

Host - (i) a human or animal body in which a resident microbiota lives; (ii) a human or animal body colonized and attacked by bacterial pathogens; (iii) in the context of bacterial viruses, the bacterium that is attacked by bacteriophage

Adherence - The initial step in the pathogenesis process, where microbes attach to host cells or surfaces.

Invasion - The process by which pathogens penetrate host tissues, allowing them to enter the host and establish an infection.

Evasion - The strategies employed by pathogens to evade the host's immune system, enabling them to survive and multiply within the host.

Transmission - The process by which pathogens are spread from one host to another, facilitating the propagation of infection.

keystone pathogen - Low abundance in healthy microbiota can have a significant impact on the microbial community when their population increases or becomes active.

dominant pathogen - High abundance can directly induce inflammation/dysbiosis by outcompeting microbes and/or producing virulence factors that cause tissue damage.