T — Togaviruses (Chikungunya Virus)
Chikungunya virus (CHIKV) is an alphavirus within the family Togaviridae. It is an enveloped, positive-sense RNA virus whose genome encodes nonstructural proteins (nsP1–4) involved in replication and structural proteins forming the capsid and envelope glycoproteins (E1 and E2). Entry occurs via receptor-mediated endocytosis, followed by low-pH-triggered membrane fusion.
Following transmission by Aedes mosquitoes, CHIKV infects fibroblasts, skeletal muscle cells, and joint-associated tissues. Viral replication induces strong type I interferon responses, but viral proteins counteract aspects of innate signaling to permit early amplification.
Acute disease is characterized by high fever, rash, and severe symmetric polyarthralgia. Unlike many arboviruses, chikungunya frequently leads to chronic inflammatory arthritis, persisting months to years. Persistent viral RNA and prolonged immune activation, including macrophage infiltration and cytokine production (e.g., IL-6, TNF-α), are thought to contribute.
Viral evolution has enhanced epidemic potential; for example, mutations in the E1 glycoprotein increased fitness in Aedes albopictus, facilitating global spread.
Research priorities include understanding chronic joint pathology, host genetic susceptibility, antiviral targets within the replication complex, and development of live-attenuated and virus-like particle vaccines.
Chikungunya virus (CHIKV) is an alphavirus within the family Togaviridae. It is an enveloped, positive-sense RNA virus whose genome encodes nonstructural proteins (nsP1–4) involved in replication and structural proteins forming the capsid and envelope glycoproteins (E1 and E2). Entry occurs via receptor-mediated endocytosis, followed by low-pH-triggered membrane fusion.
Following transmission by Aedes mosquitoes, CHIKV infects fibroblasts, skeletal muscle cells, and joint-associated tissues. Viral replication induces strong type I interferon responses, but viral proteins counteract aspects of innate signaling to permit early amplification.
Acute disease is characterized by high fever, rash, and severe symmetric polyarthralgia. Unlike many arboviruses, chikungunya frequently leads to chronic inflammatory arthritis, persisting months to years. Persistent viral RNA and prolonged immune activation, including macrophage infiltration and cytokine production (e.g., IL-6, TNF-α), are thought to contribute.
Viral evolution has enhanced epidemic potential; for example, mutations in the E1 glycoprotein increased fitness in Aedes albopictus, facilitating global spread.
Research priorities include understanding chronic joint pathology, host genetic susceptibility, antiviral targets within the replication complex, and development of live-attenuated and virus-like particle vaccines.