The baculoviruses, are a family of large rod-shaped viruses, divided into two genera: nucleopolyhedroviruses (NPV) and granuloviruses (GV). Baculoviruses have species-specific tropisms among the invertebrates with over 600 host species having been described. Moth larval is the most common hosts but sawflies, mosquitoes, and shrimp are also known hosts. The viruses are not known to replicate in mammalian or other vertebrate animal cells.
In the early sixteenth century the first records of Baculovirues were found in literature in which it was referred to as “wilting disease. Baculoviruses were used widely as biopesticides in crop fields. Since the 90s they have been used to produce complex eukaryotic proteins in insect cell cultures. These proteins are used in research and vaccines in humans and animals.
The viruses’ life cycle involves two distinct forms of virus. Occlusion derived virus is present in a protein matrix and is responsible for the primary infection of the host while the budded virus is released, during the secondary infection, from the infected host cells.
Usually infection occurs when a host feeds on plants that are contaminated with the occluded form of the virus. It can be divided into three distinct phases: early, late, and very late phase.
BV is produced in the late phase while ODV is produced in the very late phase. Occlusion bodies are released when cells lyse and further spread infection to next host. Extensive lysis of cells frequently causes the host insect to melt thus the name wilting disease. Autographa californica multicapsid nucleopolyhedrovirus is the most study baculovirus. It was isolated from the alfalfa looper.