Infectious Disease Society 08.26

Endotoxins

Structural bacterial toxins (e.g., lipopolysaccharides) that form part of the outer cell wall and are released when the bacterium breaks down.

Exotoxins

Toxic proteins synthesized by bacteria and actively secreted into the surrounding microenvironment.

Virion

A complete, structurally sound, and infectious virus particle.

Capsid

The protective protein shell or coat surrounding the viral nucleic acid genome.

Capsomere

Morphological protein subunits that assemble to form the viral capsid.

Nucleocapsid

The combined structure of the viral nucleic acid genome surrounded by its protein capsid.

Viral Envelope

A outer lipid membrane surrounding the nucleocapsid in certain viruses, derived from host cell membranes modified with viral glycoproteins.

Tegument

The protein-filled space located between the viral envelope and the nucleocapsid.

Icosahedral Symmetry

A viral capsid structure composed of triangular faces exhibiting 5-3-2 rotational symmetry.

Helical Symmetry

A viral capsid symmetry where capsomeres are arranged in a spiral staircase configuration around the viral nucleic acid.

Complex Viruses

Viruses with brick-shaped virions containing multiple outer coats, lateral bodies, and a nucleic acid core (e.g., smallpox).

Productive Infection

A viral infection cycle producing high quantities of new infectious progeny virions, usually resulting in host cell death.

Chronic Persistent Infection

A low-level productive viral replication cycle where the host cell survives long-term while continually shedding virus.

Abortive Infection

A viral infection where replication is interrupted and fails to produce any progeny virions.

Latent Infection

An infection where the viral genome remains quiescent inside host cells with minimal gene expression, capable of reactivating later.

Viral Transformation

An outcome of viral infection where the host cell undergoes heritable phenotypic changes leading to immortalization or malignancy.