Infectiological Terminology I (Pathogen)
Term and Explanation
These microorganisms are nonpathogenic; their natural habitat is dead organic matter.
Unicellular or metazoan organism living in or on an organism of another species (host) on the expense of the host
Normal inhabitants of skin and mucosa; the normal flora is thus the total commensal population
Classic disease-causing pathogens
Opportunists or facultatively pathogenic microorganisms
Can cause disease in immunocompromised individuals given an “opportune” situation; these are frequently germs of the normal flora or occasionally from the surrounding environment, animals, or other germ carriers
Capacity of a pathogen species to cause disease.
Sum of the disease-causing properties of a strain of a pathogenic species
periodTime between infection and manifestation of disease symptoms; this specific disease characteristic can be measured in hours, days, weeks,
or even years
A parasitological term: time between infection and first appearance of products of sexual reproduction of the pathogen (e.g., worm eggs in stool of a host with helminthosis)
The totality of host species “susceptible” to infection by a given pathogen
Minimum infective dose
Smallest number of pathogens sufficient to
cause an infection
Mode of infection
Method or pathway used by pathogen to invade.
Microbiological presence of microorganisms on objects, in the environment, or in samples for analysis
Presence of microorganisms on skin or mucosa; no penetration into tissues; typical of normal flora; pathogenic microorganisms occasionally also show colonization behavior
Invasion of a host organism by microorganisms, proliferation of the invading organisms, and host reaction
Inapparent (or sub-clinical) infection
Infection without outbreak of clinical symptoms.
(or clinical infection)
Infection with outbreak of clinical symptoms
Frequency of clinical manifestation of an infection in disposed individuals
Infection arising from the colonizing flora
Infection arising from invasion of host by microorganisms from sources external to it
Infection acquired during hospitalization (urinary tract infections, infections of the respiratory organs, wound infection,
Infection that remains restricted to the portal of entry and surrounding area
Lymphogenous and/or hematogenous spread of invading pathogen starting from the portal of entry; infection of organs to which pathogen shows a specific affinity (organo-tropism); three stages: incubation, generalization, organ manifestation
Systemic disease caused by microorganisms and/or their toxic products; there is often a localized focus of infection from which pathogens or toxic products enter the bloodstream continuously or in intermittent phases
Brief presence of microorganisms in the bloodstream
Occurrence of a second infection in the course of a first infection
Series of infections by the same pathogen
Series of infections by different pathogensClick Download bellow to download Omokoshaban.com News Updates, and Education Mobile App.