TABLE 2.

Proposed revisions to terminology of microbial pathogenesis in the context of the damage framework

Term	Revised definition
Carrier state	Synonymous with colonization
Chronicity	Synonymous with persistence
Colonization	A state of infection that results in a continuum of damage from none to great, with the latter leading to the induction of host responses that could eliminate or retain the microbe, or progress to chronicity or disease; for organisms that induce no damage during infection this state is indistinguishable from commensalism
Commensal	Microbe that induces either no damage or clinically inapparent damage after primary infection; a state that is thought to be established early in life
Commensalism	A state of infection that results in either no damage or clinically inapparent damage to the host, though it can elicit an immune response
Damage	The interruption of normal tissue structure and/or function of the host that applies at the cellular, tissue, and organ levels (necrosis, apoptosis, mutation, synaptic blockage, and malignant transformation are examples of damage at the cellular level; granulomatous inflammation, fibrosis, tumor are examples of damage at the tissue level; Ductal obstruction is an example of damage at the organ level); the presence of a microbe-specific immune response may be indicative of a heretofore unrecognized manifestation of damage
Elimination	Removal of the microbe from the boundaries of the host by either physical factors, interference by host flora, an immune response, or therapy
Infection	Acquisition of a microbe by host; most infections are followed by multiplication of the microbe in the host, but this is not universal because some helminth infections can involve a single organism that does not replicate in the host
Infectious disease	The clinical manifestation of damage that results from a host-microbe interaction
Latency	Synonymous with persistence, this term is often used to describe infections that are asymptomatic over long periods of time but can evolve into overt disease
Persistence	A state of infection in which the host response does not eliminate the microbe, resulting in continued damage over time; persistence may evolve into overt disease, depending on the balance of the host-microbe interaction (Fig. 1)
Pathogen	A microbe capable of causing host damage (as defined in reference 7)
Symbiosis and mutualism	A state of infection whereby both the host and the microbe benefit as a consequence of infection