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Water: Microbial

Thesaurus of Terms Used in Microbial Risk Assessment: 5.3  Pathogen Characterization or Infectious Disease Hazard Characterization Terms

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agent of disease

A factor, such as a microorganism, chemical substance, or form of radiation, whose presence, excessive presence, or (in deficiency diseases) relative absence is essential for the occurrence of a disease.  A disease may have a single agent, a number of independent alternative agents (at least one of which must be present), or a complex of two or more factors whose combined presence is essential for the development of the disease.  See also causality.  (Last 1983)

amplification

Multiplication or replication of a microorganism within a given medium.  (ILSI 2000)

anaerobic

Anaerobic processes or organisms do not use oxygen. The term anaerobic can also refer to an oxygen-free environment. (Jones 2006)

anti-microbial

An agent that kills microbes.  (EPA 2005b)
This term is sometimes more broadly applied to agents that slow microbial growth or inactivate microbial functions. Antibiotics, antiseptics, disinfectants, and biocides are all anti-microbial.

attenuated (strain)

To reduce the virulence (infectivity) of a pathogenic microorganism.  (CancerWeb 2005)
RELATED TERMS:strain

avirulent
  1. Not virulent.  (CancerWeb 2005, Stedman 2005)
  2. Avirulent mutants of a bacterium or virus have lost the capacity to infect a host productively, that is, to make more bacterium or virus.  (Jones 2006)
bacteria
  1. Singular: bacterium.  Microscopic single-celled organisms with rigid walls.  Bacteria are found almost everywhere.  Some bacteria in soil, water or air can cause human disease.  (CRCWQT 2002)
  2. Single-cell, independently replicating microorganisms that lack a membrane-bound nucleus and other organelles.  (FDA 2001)
  3. One-celled microorganisms that are either free-living or parasitic, some of which may cause illness in humans and/or animals.  (USDA 2004)

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bactericidal
  1. Capable of killing bacteria.  Some antibiotics are either bacteriocidal or bacteriostatic in their action.  (CancerWeb 2005)
  2. Causing the death of bacteria.  (Stedman 2005)
  3. A treatment is said to be bacteriocidal when it causes the death of bacterial cells. (Jones 2006)
biological contaminant

Living organisms or derivates (e.g. viruses, bacteria, fungi, and mammal and bird antigens) that can cause harmful health effects when inhaled, swallowed, or otherwise taken into the body.  (EPA 2005b)
RELATED TERMS: contaminant

coliforms
  1. A group of bacteria found in the intestines of animals (including humans), and also in soil, vegetation, and water.  (CRCWQT 2002)
  2. The most common form of bacteria found in untreated water.  The presence of this group of non-pathogenic bacteria in drinking water is an indicator that the water may be contaminated by sewage and/or other similar material and should not be ingested.  Fecal coliform bacteria, of which E. coli is one type, live in the intestines of warm-blooded animals.  Pathogenic coliforms can cause diarrhea and other serious health problems if the bacteria are ingested.  (FDA 2001)
    RELATED TERMS: bacteria, indicator, indicator organisms
colonization
  1. The formation of compact population groups of the same type of microorganism, as the colonies that develop when a bacterial cell begins reproducing.  (CancerWeb 2005, Stedman 2005)
  2. The process in which microorganisms live and reproduce in or on either the human body without causing disease, or an inanimate object such as a disinfection machine (Queensland Health 2005)
  3. Implantation and growth of a microorganism on a host.  (USDA 2004)
colony forming unit          (ACRONYM: cfu, CFU)
  1. An individual cell which is able to clone itself into an entire colony of identical cells.  (CancerWeb 2005)
  2. Unit of measurement for viable bacteria numbers.  (USDA 2004)

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commensal (commensalism)
  1. Living on or within another organism and deriving benefit without injuring or benefiting the other individual.  An organism living on or within another, but not causing injury to the host.  A type of symbiosis where two (or more) organisms from different species live in close proximity to one another, in which one member is unaffected by the relationship and the other benefits from it. (CancerWeb 2005)
  2. Pertaining to or characterized by commensalism.  An organism participating in commensalism.  (Stedman 2005)
  3. A symbiotic relationship in which one species benefits while the other is unaffected.  (Jones 2006)
contagious
  1. Capable of being transmitted from one person to another by contact or close proximity.  (CDC 2005)
  2. Transmitted by contact; in common usage, “highly infectious.”  (MERREA 2005)
    RELATED TERMS: infectiousness, infectivity, transmissible
contaminant
  1. A substance that is either present in an environment where it does not belong or is present at levels that might cause harmful (adverse) health effects.  (ATSDR 2004)
  2. Any physical, chemical, biological, or radiological substance or matter that has an adverse effect.  (CRCWQT 2002)
contamination

Contact with an admixture of an unnatural agent, with the implication that the amount is measurable.  The deposition of unwanted radioactive material on the surfaces of structures, areas, objects, or people.  It may also be airborne, external, or internal (inside components or people).  (RAIS 2004)

culture

In microbiology, the growth of an organism in or on a nutrient medium.  (MERREA 2005)

emerging pathogens

An illness-causing microorganism that is either:

  • previously unknown to be a human pathogen;
  • not expected to occur in a particular food;
  • has caused a dramatic increase in new cases of illness.  (FDA 2001)
etiologic

Cause of disease/illness, as in the etiology of smallpox is the variola virus.  (MERREA 2005)

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exponential growth (rate)

  1. A rate of growth of an organism, a part of an organism, or a population of organisms which, when graphed, produces an exponential or logarithmic curve.  Such a rate occurs, for example: during the exponential growth phase, when a population of bacterial (or other) cells divide at a constant rate so that the total number of cells doubles with each division.  (CancerWeb 2005).
  2. A period in the course of growth of a bacterial culture in which maximal multiplication is occurring by geometrical progression; thus, if the logarithms of their numbers are plotted against time, they will form a straight upward line.  (Stedman 2005)
fecal coliform
  1. Bacteria found in the intestinal tracts of mammals, this bacteria in water or sludge is an indicator of pollution and possible contamination by pathogens. (EPA 2005e)
  2. A subgroup of bacteria of the coliform type that live mainly in the gut of warm-blooded animals. The detection of fecal coliforms in water is an indication of poor water quality and the possibility of pathogenic organisms being present.  (CRCWQT 2002)
    RELATED TERMS: coliforms, indicator, indicator organisms
flora
  1. Intestinal flora:The various bacteria that normally live in the intestinal tract.  Normal intestinal flora are important to aid in the breakdown of certain foods for absorption.  (CancerWeb 2005)
  2. The population of microorganisms inhabiting the internal and external surfaces of healthy conventional animals.  (Stedman 2005)
food ecology

The study of the interactions between factors inherent (pH, water activity, nutrients) in or external (temperature, gaseous environment) to a food and the composition of its specific microbial population.  (ILSI 2000)

foodborne pathogen

A microorganism that is capable of causing disease and that is transmissible by ingestion of food.  (ILSI 2000)

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frank pathogen

A microorganism capable of producing disease in both healthy and compromised persons.  (ILSI 2000)
RELATED TERMS: opportunistic pathogen

fungi (fungus)
  1. Molds, mildews, yeasts, mushrooms, and puffballs, a group of organisms lacking in chlorophyll (i.e., are not photosynthetic) and which are usually non-mobile, filamentous, and multicellular.  Some grow in soil, others attach themselves to decaying trees and other plants whence they obtain nutrients.  Some are pathogens, others stabilize sewage and digest composted waste.  (EPA 2005b)
  2. Funguses, or fungi, are types of plants that have no leaves, flowers or roots. Both words, funguses and fungi, are the plural of fungus.  (EPA 2005e)
  3. Fungi includes organisms such as slime molds, mushrooms, smuts, rusts, mildews, moulds, stinkhorns, puffballs, truffles and yeasts.  All are classified in this kingdom because they absorb food in solution directly through their cell walls and reproduce through spores.  None conduct photosynthesis.  (CancerWeb 2005)
  4. Simple plants called “Saprophytes” that lack chlorophyll (the green coloring that plants use to make food).  Because fungi lack chlorophyll, they cannot produce their own food.  Therefore, they must take carbohydrates, proteins, and other nutrients from the animals, plants, or decaying matter on which they live.  (FDA 2001)
  5. A division of eukaryotic organisms that grow in irregular masses, without roots, stems, or leaves, and are devoid of chlorophyll or other pigments capable of photosynthesis.  Each organism (thallus) is unicellular to filamentous, and possesses branched somatic structures (hyphae) surrounded by cell walls containing glucan or chitin or both, and containing true nuclei.  They reproduce sexually or asexually (spore formation), and may obtain nutrition from other living organisms as parasites or from dead organic matter as saprobes (saprophytes).  Relatively few fungi are pathogenic for humans, whereas most plant diseases are caused by fungi.  (Stedman 2005)
host specificity

The characteristic of a pathogen that renders it capable of infecting one or more specific hosts.  (ILSI 2000)

independent action

The mean probability of infection per inoculated microorganism is independent of the number of organisms in the inoculum (disease). (Meynell and Stocker 1957)
RELATED TERMS:Contrast with quorum sensing

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indicator
  1. In biology, any biological entity or processes, or community whose characteristics show the presence of specific environmental conditions.  In chemistry, a substance that shows a visible change, usually of color, at a desired point in a chemical reaction.  A device that indicates the result of a measurement; e.g. a pressure gauge or a moveable scale.  (EPA 2005b)
  2. There are limitation and assumptions associated with using a single pathogen as a representative for a class of pathogens or a nonpathogenic indicator species for a pathogen of pathogen group.  Surrogate and indicator are synonymous.  (ILSI 2000 text)
    RELATED TERMS: coliforms, surrogate, indicator organisms

The term indicator is used in a several ways.  In the ecological context it refers to a species that indicates the overall state of the local ecosystem.  Indicator is also used in the general sense to mean anything that can be correlated with the presence of the hazard.  For example, fecal sterols can be an indicator of fecal material. In this case the assumption is that fecal material presents a hazard due to the presence of human pathogens.  The most common use of indicator in the context of microbial risk assessment is indicator bacteria, which are bacteria whose presence indicates the presence of fecal material.   An indicator may be linked directly to a health outcome through epidemiology.  For example, the presence of the indicator bacteria, E. coli, in recreational water can be statistically linked to an increase in gastrointestinal illness in swimmers.

indicator, fecal

A microbiological organism (e.g., E. coli), or group of organisms (e.g., fecal coliforms), that is commonly and specifically associated with fecal material or illness risk among bathers.  (NZ 2002)
RELATED TERMS: coliforms

infectious agent

Any organism, such as a pathogenic virus, parasite, or bacterium, that is capable of invading body tissues, multiplying, and causing disease.  (EPA 2005b)
RELATED TERMS: toxico-infectious pathogen, toxinogenic pathogen

infectious pathogen

One of three broad classes of foodborne pathogens—infectious, toxico-infectious or toxigenic—based on their modes of pathogenicity.  Infectious pathogens typically have a three-step process by which they elicit a disease response: ingestion of viable cells, the attachment of these cells to specific locations along the gastro-intestinal tract (or some other mechanisms for avoiding being swept away due to peristalsis), and the invasion of either the epithelium (gastroenteritis) or the body proper (septicaemia).  (Buchanan 2000)

infectiousness
  1. The characteristic of a disease that concerns the relative ease with which it is transmitted to other hosts.  A droplet spread disease, for instance, is more infectious than one spread by direct contact.  The characteristics of the portals of exit and entry are thus also determinants of infectiousness, as are the agent characteristics of ability to survive away from the host and of infectivity.  (MERREA 2005)
  2. The state or quality of being infectious.  (Stedman 2005) 
    RELATED TERMS: infectivity, infectibility

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infectivity
  1. The proportion of persons exposed to a causative agent who become infected by an infectious disease.  (CDC 2005)
  2. The characteristic of a microorganism that allows it to infect and subsequently survive and multiply within a susceptible host.  (Toma 1999)
  3. The characteristic of a disease agent that embodies capability to enter, survive and multiply in the host; a measure of infectivity is the secondary attack rate; the proportion of exposures, in defined circumstances, that results in infection.  (MERREA 2005)
    RELATED TERMS: infectiousness, infectibility
inoculum
  1. Bacteria or fungi injected into compost to start biological action.
  2. A medium containing organisms, usually bacteria or a virus, that is introduced into cultures or living organisms. (EPA 2005b)
  3. The amount microorganisms introduced into a host.  (MERREA 2005)
invasiveness

Degree to which an organism is able to spread through the body from a focus of infection.  (CancerWeb 2005)

isolate

Isolate refers to a laboratory maintained stock or controlled propagation through host passages source of microorganisms.  Isolates are used in the volunteer human feeding studies.  In this context, it should not be implied that these isolates represent clonal populations of pathogens.  There may be genetic variation within a stock batch and between generations.  (EPA 2005f)

log inactivation

SEE: log reduction

log reduction

“Log” stands for logarithm, which is the exponent of 10.  For example, log2 represents 102 or 10 x 10 or 100.  Log reduction stands for a 10-fold or one decimal or 90% reduction in numbers of recoverable bacteria in a test food vehicle.  Another way to look at it is: 1 log reduction would reduce the number of bacteria 90%.  This means, for example, that 100 bacteria would be reduced to 10 or 10 reduced to 1.  (FDA 2001)
RELATED TERMS:log inactivation

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logarithmic growth curve (phase)
  1. The steepest slope of the growth curve of a culture—the phase of vigorous growth during which cell number doubles every 20-30 minutes.  (CancerWeb 2005)
  2. Steep part of the growth curve of a bacterium or eukaryotic cell in culture during which cells divide rapidly. (Jones 2006)
    RELATED TERMS:exponential growth (rate)
mechanical vector

A vector that conveys pathogens to a susceptible individual without essential biological development of the pathogens in the vector, as in the transfer of septic organisms on the feet or mouth parts of the housefly.  (CancerWeb 2005, Stedman 2005)
RELATED TERMS:vector

mechanism of action

SEE:mode of action

mechanism of infection

The process by which a microorganism establishes itself in a host, including transmission, invasion, and multiplication.  (ILSI 2000)

medium
  1. Material (e.g., air, water, soil, food, consumer products) surrounding or containing an agent.  (IPCS 2004)
  2. (Media) Specific environments—air, water, soil—that are the subject of regulatory concern and activities. (RAIS 2004)
    RELATED TERMS: environmental medium
microbial growth
  1. The amplification or multiplication of microorganisms such as bacteria, algae, diatoms, plankton, and fungi.  (EPA 2005b)
  2. Growth of microorganisms such as bacteria, algae, diatoms, plankton and fungi.  (CRCWQT 2002)
microbial pesticides

Microorganisms that kill or inhibit pests, including insects or other microorganisms.  Sometimes microorganisms get rid of pests simply by growing larger in numbers, using up the pests’ food supply, and invading the pests’ environment.  (EPA 2005e)

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microorganism
  1. Bacteria, yeasts, simple fungi, algae, protozoans, and a number of other organisms that are microscopic in size.  Most are beneficial but some produce disease.  Others are involved in composting and sewage treatment.  (EPA 2005e)
  2. Living organisms that can be seen individually only with the aid of a microscope.  (CRCWQT 2002)
  3. A microscopic life form that cannot be seen with the naked eye.  Types of microorganisms include: bacteria, viruses, protozoa, fungi, yeasts, and some parasites and algae.  (FDA 2001)
    RELATED TERMS: pathogen

Prions are microscopic infectious agents and are sometimes grouped with microorganisms even though prions lack genetic material.

mobility

The ability of a chemical element or a pollutant to move into and through the environment (e.g., the mobilization of an element from a water column to sediment).  (RAIS 2004)

mode of action

The term “mode of action” is defined as a sequence of key events and processes, starting with interaction of an agent with a cell, proceeding through operational and anatomical changes, and resulting in cancer formation.  Mode of action is contrasted with “mechanism of action,” which implies a more detailed understanding and description of events, often at the molecular level, than is meant by mode of action.  The toxicokinetic processes that lead to formation or distribution of the active agent to the target tissue are considered in estimating dose but are not part of the mode of action as the term is used here.  There are many examples of possible modes of carcinogenic action, such as mutagenicity, mitogenesis, inhibition of cell death, cytotoxicity with reparative cell proliferation, and immune suppression.  (EPA 2005a)
RELATED TERMS:mechanism of action

opportunistic pathogen

A microorganism that does not ordinarily cause disease but that, under certain circumstances (e.g., impaired immune response resulting from other disease or drug treatment), elicits a pathogenic response.  (ILSI 2000)

parasite
  1. An organism which obtains food and shelter from another organism (for example, Giardia).  (CancerWEB 2005)
  2. A plant or animal that lives on or in another plant or animal, while making no beneficial contribution to that host.  (FDA 2001)
    RELATED TERMS: protozoa

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pathogen
  1. Microorganisms (e.g., bacteria, viruses, or parasites) that can cause disease in humans, animals and plants.  (EPA 2005b)
  2. A bacterial organism typically found in the intestinal tracts of mammals, capable of producing disease.  (EPA 2005e)
  3. A disease-causing microorganism; includes various types of bacteria, viruses, fungi and protozoa.  (CRCWQT 2002)
  4. Any microorganism that is infectious or toxigenic and causes disease.  Pathogens include parasites, viruses, and some fungi/yeast and bacteria.  (FDA 2001)
  5. Organisms capable of causing disease.  (MERREA 2005)
  6. A disease-causing agent, such as a certain bacterium, parasite, virus, or fungus.  (USDA 2004)
  7. A pathogen is a virus or microorganism (including its viruses and plasmids, if any) that has the ability to cause disease in other living organisms (i.e., humans, animals, plants, microorganisms). (OSTP 1986)
    RELATED TERMS: virulence-factor activity relationship

Note that only one of the definitions of pathogen includes plasmids.  That definition is from the 1986 Coordinated Framework for Regulation of Biotechnology. In 1986 the term virulence-factor activity relationship had not yet been proposed. 

pathogen characterization

Evaluation of the characteristics of a pathogen that affect its ability to be transmitted to and cause disease in the host.  (ILSI 2000)

pathogenesis
  1. The origin and development of disease.  (CancerWeb 2005)
  2. The postulated mechanisms by which the etiologic agent produces disease.  (MERREA 2005)
  3. The pathologic, physiologic, or biochemical mechanism resulting in the development of a disease or morbid process.  (Stedman 2005)
    RELATED TERMS:etiologic

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pathogenicity
  1. The proportion of persons infected, after exposure to a causative agent, who then develops clinical disease.  (CDC 2005)
  2. The property of an organism that determines the extent to which overt disease is produced in an infected population, or the power of an organism to produce disease.  Also used to describe comparable properties of toxic chemicals.  Pathogenicity of infectious agents is measured by the ratio of the number of persons developing clinical illness to the number exposed to infection.  (MERREA 2005)
plaque forming unit          (ACRONYM: pfu/PFU)

Refers to any entity which can give rise to a plaque.  For example: if a phage stock solution has 1010 pfu/mL, it means that every mL of this stock has 1010 phage particles which can form plaques.  This (pfu/mL) is the conventional way to refer the concentration of a phage preparation.  (CancerWeb 2005)

practical quantitation limit

The lowest level of quantitation that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions.  (EPA 2004)

predictive microbiology

Analytical methods including mathematical modeling to estimate changes in bacterial numbers under different environmental or processing conditions, thus allowing assessment of the degree of contamination of a given medium.  (ILSI 2000)

prion

A proteinaceous infectious agent that behaves as an inheritable trait, although it contains no nucleic acid.  Examples are PrPSc, the agent of scrapie in sheep and bovine spongiform encephalopathy, and Psi, which confers an inherited state in yeast. (Jones 2006)

protozoa
  1. One-celled animals that are larger and more complex than bacteria.  May cause disease.  (EPA 2005b)
  2. Singular: protozoan.  Single-celled microscopic animal.  Plural protozoa.  (CRCWQT 2002)

The use of the term “animals” in the first definition is phylogentically incorrect.

quorum sensing

Quorum sensing is a form of communication between bacteria based on the use of signalling molecules that allows bacteria to coordinate their behaviour.  The accumulation of signalling molecules in the environment enables a single cell to sense the number of bacteria (cell density).  Behavioural responses include adaptation to availability of nutrients, defence against other microorganisms that may compete for the same nutrients, and the avoidance of toxic compounds potentially dangerous for the bacteria.  For example, it is very important for pathogenic bacteria during infection of a host (e.g., humans, other animals or plants) to coordinate their virulence in order to escape the immune response of the host in order to be able to establish a successful infection.  (FAO/WHO 2003b)
RELATED TERMS: contrast with minimum infective dose, independent action

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resistance
  1. In a body subject to infection, the sum total of body mechanisms that interpose barriers to the invasion or multiplication of infectious agents or to damage by their toxic products.   (APHA 1995)
  2. In a pathogen, the ability of a microorganism to adapt to and overcome the effects of antimicrobial drugs and/or host immune responses.  (ILSI 2000)
spore
  1. Highly resistant dehydrated form of reproductive cell produced under conditions of environmental stress.  Usually have very resistant cell walls (integument) and low metabolic rate until activated.  Bacterial spores may survive quite extraordinary extremes of temperature, dehydration or chemical insult.  Gives rise to a new individual without fusion with another cell.  (CancerWeb 2005)
  2. A thick-walled protective structure produced by certain bacteria and fungi to protect their cells.  (FDA 2001)
  3. Reproductive cells that are shed by an organism and divide to generate a new organism. In bacteria, they are produced by the special process of sporulation. I n plants, they are haploid cells produced by meiosis.  In fungi, they may be haploid cells produced by meiosis (sexual spores) are somatic cells that are cast off to make new individuals (asexual spores). (Jones 2006)
  4. A specialized type of resting Gram positive bacterial cell, with a thick coat. Highly resistant to heat and chemicals.  (Queensland Health 2005)
  5. The asexual or sexual reproductive body of fungi or sporozoan protozoa.  A cell of a plant lower in organization than the seed-bearing spermatophytic plants.  A resistant form of certain species of bacteria.  (Stedman 2005)
strain
  1. A variant of a species of bacteria.  Some may be pathogenic and some may be benign.  For example, most E. coli are neutral or helpful to people, but E. coli O157:H7 is a strain of E. coli that is harmful to people.  (FDA 2001)
  2. A population of homogeneous organisms possessing a set of defined characteristics; in bacteriology, the set of descendants that retains the characteristics of the ancestor; members of a strain that subsequently differ from the original isolate are regarded as belonging either to a substrain of the original strain, or to a new strain.  (Stedman 2005)
tolerance of pathogens to control

The ability of a microorganism to withstand specific environmental control measures (e.g., irradiation, temperature extremes, biocides, disinfection).  (ILSI 2000)

toxico-infectious pathogen

One of three broad classes of foodborne pathogens—infectious, toxico-infectious or toxigenic—based on their modes of pathogenicity.  Toxico-infectious agents follow a similar three-step process, except that instead of invading the epithelium or body, they remain in the gastro-intestinal tract, where they either produce or release toxins that affect sites of the epithelium and/or within the body.  (Buchanan 2000)
RELATED TERMS: infectious pathogen, toxinogenic pathogen

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toxin

A poison that is produced by microorganisms, carried by fish, or released by plants.  (FDA 2001)
RELATED TERMS: toxicant

toxinogenic pathogen

One of three broad classes of foodborne pathogens—infectious, toxico-infectious or toxigenic—based on their modes of pathogenicity.  Toxinogenic bacteria are differentiated on the basis that they cause disease by producing toxins in foods prior to its ingestion.  (Buchanan 2000)
RELATED TERMS:infectious pathogen, toxico-infectious pathogen

transmissible

Capable of being transmitted (carried across) from one person to another, as a transmissible disease, an infectious or contagious disease.  (CancerWeb 2005, Stedman 2005)
RELATED TERMS: transmission of infection

vegetative (bacterial) cell

Bacteria that are in the growth and reproductive phase, i.e., not spores.  (Queensland Health 2005)

viable but not (non-) culturable          (ACRONYM: VNBC, VNC)

VBNC bacteria represent the part of the bacteria population, which is not able to grow in usual culture media and which cannot be resuscitated by traditional resuscitation techniques but which retain metabolic activity detected by various methods in the conditions tested.  (Besnard et al. 2002)

virulence
  1. The proportion of persons with clinical disease, who after becoming infected, become severely ill or die.  (CDC 2004)
  2. The degree of intensity of the disease produced by a microorganism as indicated by its ability to invade the tissues of a host and the ensuing severity of illness.  (ILSI 2000)
  3. The pathogenic or poisonous potential of bacteria, fungi, or other agents.  (USDA 2004)
virulence factor

A general term for molecules that are produced by pathogens and allow pathogens to invade host organisms, cause disease, or evade immune responses (Jones 2006)

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virulence-factor activity relationship          (ACRONYM: VFAR)

VFAR is a concept that was developed as a way to relate the architectural and biochemical components of a microorganism to its potential to cause human disease. (Jenkins et al. 2004)

virus
  • A non-cellular particle that consists minimally of protein or nucleic acid (DNA or RNA).  In order to survive, it must replicate inside another cell, such as a bacterium or a plant and animal cell.  (FDA 2001)
  • A large group of infectious agents, much smaller than bacteria, that is able to be viewed only through an electron microscope.  They are not cells, but biologically active particles that vary in size from 0.01 to 0.1 microns.  (CRCWQT 2002)
waterborne pathogen

A microorganism capable of causing disease that may be transmitted via water and acquired through ingestion, bathing, or by other means.  (ILSI 2000)

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