Baculoviruses are pathogens that infect insects and other arthropods. They are small, double-stranded DNA viruses. The Nuclear polyhedrosis virus (NPV) is a baculovirus that infects insects like moths and butterflies. It forms an extremely stable crystal capsule called the occlusion body that protects the virus in the environment. When an insect eats a contaminated plant, the alkaline environment of its gut dissolves the occlusion body and releases virus particles that infect the gut cells. The virus then replicates rapidly within the host's cells until it dies, filled with new virus particles. NPV spreads by infected insects shedding virus crystals that can then infect other insects.

1. BHARATHIDASAN UNIVERSITY
TIRUCHIRAPPALLI-24
DEPARTMENT OF BIOTECHNOLOGY
BACULOVIRUS-NPV

2. Baculoviruses :
Baculoviruses are pathogens that attack
insects and other arthropods.
Like some Human viruses , they are
extremely small ,double - stranded DNA that codes for
genes needed for virus establishment and reproduction.
Immature forms of moth species are the
most common hosts, but these viruses have also been found
infecting sawflies , mosquitoes, and shrimp.

3. Baculoviruses have very species- specific tropisms
among the invertebrates with over 600 host specie Have
been described.
Typically initial infection occurs when a susceptible
host insect feds on plants that are contaminated with The
occluded form of the virus.
Baculoviruses infection can be divided to three distinct
phases:
Early(0-6 hpost –infection),
Late(6-24 h p.i.)
Very late phase(18-24 to72 h p.i.)

4. NPV:
The Nuclear polyhedrosis virus (NPV),
part of family of baculoviruses, is a virus ,
affecting insects predominantly moths and
butterfly.
It has been used as a pesticide.
VIRUS CLASSIFICATION:
Group: Group I(dsDNA)
Family: Baculoviridae

5. Descripition:
The polyhedral capsid from
which the virus gets its name extremely
stable protein crystal that protects the virus
in the external environment.
It dissolves in the alkaline midgut
of moths and butterflies to release the virus
particle and infect the larva.
An example of an insect that it
infects is the fall webworm.

6. Discoloration (brown and yellow)
Stress (regurgitation)
Decomposition (liqufication)
Lethargic
(slow
movement to nomovement at all; refusal to eat)

7. Transmissibility:
NPV is transferred from insect to insect through
crystals in their bodily emissions.
The virus is unable to infect the humans in the way
it does insects, because human cells are acid-based and NPV
requires an alkaline cell in order to replicate.
It is possible for the virus crystals to enter human
cells, but no to replicate to the point of causing illness.

8. MODE OF ACTION OF NPV:
Occlusion bodies are ingested by insect larvae.In the
highly alkaline pH of the midgut,the occlusion body protein dissolves
and is further degraded by host alkaline proteases.
The virus particles are released from polyhedral and
subsequently attach to the peritropic membrane lining the midgut .
The lipoprotein membrane surrounding the virus
fuses with plasma membrane of the gut wall cells and liberates
nucleocapsids into the cytoplasm.

9. The nucleotide transport virus into the nucleus
of the cell and virus gene expressions begins.
The virus multiplies rapidly and eventually fills
the body of the host with virus particles.