Ascoviruses

Definition

A genus of large, enveloped DNA viruses (family Ascoviridae) that specifically infect lepidopteran larvae, causing a distinctive pathology in which infected cells develop large, membrane-bound vesicles filled with virions. Unlike typical baculoviruses that liquefy hosts, ascoviruses produce a chronic, non-lethal infection in many cases, with virions transmitted horizontally by parasitoid wasps that vector the virus between caterpillar hosts.

Etymology

From Greek askos (bladder, sac) + virus, referring to the vesicular, sac-like inclusion bodies characteristic of infected cells.

Example

Spodoptera frugiperda ascovirus 1a (SfAV-1a), which infects fall armyworm larvae, is transmitted by the parasitoid wasp Diadromus pulchellus; the wasp acquires virions during oviposition and mechanically transfers them to new caterpillar hosts.

Related Terms

• baculoviruses
• Iridoviruses
• Entomopathogenic viruses
• Parasitoid wasp
• Lepidoptera
• Viral transmission
• Cellular pathology

Usage Notes

The genus Ascovirus (family Ascoviridae, order Pimascovirales) is distinguished from other insect DNA viruses by its unique cytopathology: infected host cells cleave into virion-filled vesicles rather than undergoing complete lysis. Horizontal transmission depends almost exclusively on parasitoid wasps as biological vectors; vertical transmission appears rare. Infections are typically sublethal or slow-killing, contrasting with the acute mortality caused by many baculoviruses. The taxonomy includes multiple species named after their primary lepidopteran hosts (e.g., Heliothis virescens ascovirus, Trichoplusia ni ascovirus).