Pathogen

Any disease‐producing microorganism.

A virus, bacterium, parasitic protozoan, or other microorganism that causes infectious disease by invading the body of an organism known as the host. It should be noted that infection is not synonymous with disease because infection does not always lead to injury of the host.

An agent that causes disease, such as bacteria, viruses, fungi and parasites.

Microorganism capable of producing disease.

Production of a disease, especially the development of a disease from a specific cause or source.

Disease-causing bacteria, as distinct from those that are harmless.

A microorganism that may cause disease.

A microorganism capable of producing an infection in humans. There are four general classes: 1. (a) bacteria, bacillus (rod-shaped); (b) coccus, spherical; (c) spirillum, spiral; (d) rickettsia, small bacteria; (e) virus, ultramicroscopic; 2. fungi, mold and yeast; 3. protozoa, (a) amoeba and (b) plasmodium; 4. metazoan, round worm, tapeworm, and trichinella.

Those bacteria, fungi and viruses which parasitize man or animals and produce a disease state, as distinct from commensals which are parasitic but harmless.

A microorganism capable of producing disease such as bacterium, virus, or fungus.

Any organisms, such as bacteria or viruses, that can cause disease.

An agent that causes disease, usually referring to a microorganism such as a virus, bacterium, or fungus.

A microorganism, such as a bacterium, that parasitizes an animal (or plant) or man and produces a disease.

Micro-organisms that cause diseases, parasitizing plants, animals and humans. Some organisms are frequently pathogenic, whereas others rarely cause disease. Opportunistic pathogens are those which rarely cause serious infection in healthy people but can do so in patients with weakened immune systems (immunocompromised). Pathogens include bacteria, viruses, prions, fungi, protozoa and metazoa (multicellular microorganisms called helminths or worms). The pathogenicity of an organism is called its virulence, which is measured by the number of organisms required to cause disease.

A microorganism capable of producing a disease.

A pathogen is an organism or virus capable of inducing an ailment in a particular host or a range of hosts. The term can be associated with genera, species, and sub-specific taxa of fungi, bacteria, and other similar organisms, as well as with strains and other variants of viruses. It reflects a general tendency within the taxonomic group but doesn’t necessarily exclude the possibility that a particular race, strain, or isolate may be incapable of causing a disease in a given host. This exception is called a non-virulent (or avirulent) race, strain, or isolate of the pathogen, which is distinct from other pathogen variants that exhibit high, intermediate, or low virulence levels towards the same host. Similarly, the use of the term isn’t precluded if a specific host doesn’t develop a disease because it has a higher tolerance towards the pathogen.