Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia, Wikipedia.
Related to infectious agent: communicable disease
infectious agentPathogen, see there.
1. any power, principle or substance by which something is accomplished, or which is capable of producing a chemical, physical or biological effect such as a disease.
2. of disease; any factor whose excessive presence or relative absence is essential for the occurrence of a disease.
adrenergic neuron blocking agent
one that inhibits the release of norepinephrine from postganglionic adrenergic nerve endings.
a cytotoxic agent, e.g. a nitrogen mustard, which is highly reactive and can donate an alkyl group to another compound. Alkylating agents inhibit cell division by reacting with DNA and are used as antineoplastic agents.
substance capable of producing reversible general or local anesthesia.
cholinergic blocking agent.
change in an animal's chemical or antigenic configuration can alter its pathogenicity. For example, a case of nitrate-nitrite poisoning in a cow can become a case of nitrite poisoning after conversion of the nitrate in the rumen. Mutation and antigenic drift are other types of change that vary agent pathogenicity.
a compound that combines with metals to form weakly dissociated complexes in which the metal is part of a ring, and is used to extract certain elements from a system.
substance that produces change by virtue of its chemical composition and its effects on living tissues and organisms.
cholinergic blocking agent
one that blocks the action of acetylcholine at nicotinic or muscarinic receptors of nerves or effector organs.
only some agents are determinants of diseases in that they always cause disease, and the same disease, and the disease does not occur without the agent. Many agents require the intervention of other factors, such as anaerobicity of tissue, hepatic insufficiency or physiological stress before they can establish their pathogenicity.
ganglionic blocking agent
one that blocks cholinergic transmission at autonomic ganglionic synapses.
see neuromuscular blockade.
an organism able to live in or on the tissue of a living animal; may not necessarily cause disease.
is the interaction between precipitating and predisposing causes of disease.
a substance that acts as an electron acceptor in a chemical oxidation-reduction reaction.
are the properties which determine the pathogenicity of the agent, the solubility and acidity or biodegradability of a chemical, the virulence, adhesiveness, resistance to antibacterial agents of bacteria and viruses and so on.
a substance that acts as an electron donor in a chemical oxidation-reduction reaction.
a substance that exerts a change on the surface properties of a liquid, especially one, such as a detergent, that reduces its surface tension. Called also surfactant.
a substance capable of producing a curative effect in a disease state.
agent without disease
exemplified by the orphan viruses. The agent is of a type that causes disease, but none is associated with the presence of the particular agent.