Definition
Abortive infection	An incomplete viral life cycle in which infection is initiated that may support limited viral replication but ultimately fails to produce infectious progeny due to the absence or incompatibility of essential viral or host factors
Acute infection	The initial stage of infection, characterized by active viral replication, high viremia, and the onset of clinical symptoms
Autophagy	A highly conserved eukaryotic degradation pathway that recycles cytoplasmic components through lysosomal processing, maintaining cellular homeostasis and supporting survival under stress conditions
Cellular niches	Specialized cellular or tissue environments that enable viruses to evade clearance and maintain persistence or low-level replication
Helper virus	A virus that provides necessary functions (such as proteins or replication machinery) to complement a defective virus, enabling its genome replication and assembly into infectious particles
Host factors	Cellular proteins that may interfere with viral replication or assembly, forming part of the intrinsic antiviral defense, including interferon-stimulated genes (ISGs)
Immune-privileged	A state in which specific tissues or anatomical sites exhibit reduced immune surveillance or inflammatory responses, allowing these sites to tolerate the introduction of foreign antigens without eliciting an inflammatory immune response
Long-term manifestations	Clinical symptoms that are maintained weeks to years after the initial infection with a given virus
Low-fidelity variants of the RNA polymerase nsP4	An enzyme that synthesizes RNA with a higher error rate, making it more likely to incorporate incorrect nucleotides during viral replication (which may lead to increased genetic diversity in RNA viruses)
Lytic to non-lytic infection	The shift from virus-induced death (lytic infection) to infection without cytopathic effects (non-lytic infection)
Novel alternative human models	Models to replace or decrease animal use during experiments, including organ-on-a-chip systems, computational modeling, or in vitro cell cultures, such as the use of human induced pluripotent stem cells (iPSCs)
Opsonized antigens	Viral particles or antigens coated with host antibodies or complement proteins, facilitating recognition and uptake by phagocytic cells via Fc or complement receptors
Persistent viral material	The continued presence of viral RNA or proteins in host tissues after apparent clinical recovery, even when infectious particles are no longer produced
Post-acute sequelae	The long-term health effects or complications that persist after the acute phase of infection has resolved (e.g., chronic arthralgia)
Productive infection	A complete viral life cycle that results in the generation of infectious viral progeny
Replication output	Viral particles produced as a result of the process of viral replication within a host cell
Vectorial capacity	The overall ability of a mosquito population to transmit a pathogen to vertebrate hosts, influenced by the biting rate, vector competence, lifespan, and extrinsic incubation period
Viral debris	Non-replicative viral remnants of an infection, including residual viral RNA and proteins that linger after resolution of the initial infection
Viral persistence	In the context of alphavirus infection, we define viral persistence as any detectable viral RNA or antigen within the vertebrate host after the resolution of viremia and acute disease signs, regardless of whether active replication occurs
Viremia	The presence of infectious virus in the bloodstream