Nuclear Polyhedrosis Virus

Nuclear Polyhedrosis Virus (NPV)


The nuclear polyhedrosis virus (NPV) is a virus affecting insects, predominantly moths and butterflies. It has been used as a pesticide for crops infested by insects susceptible to contraction. Though commercialization of the viral pesticide is slow as the virus is very partial to specific species, making it only effective under certain circumstances.

The virus strain itself is protected in a polygonal structured capsid. This enables the virus to infect cells easier, and aids in reproduction of the virus. When the capsid is broken down within a host, virus strains are released and begin reproduction. Once there is a significant build up of virus, symptoms become noticeable.

This virus is not dangerous to humans, but in the fictional novel, “The Cobra Event” by Richard Preston, the strain was altered with the Variola Minor virus (small pox) to create a highly contagious and lethal neurovirus called the ‘Cobra Virus’ – which affected humans as well as insects.

Symptoms
-Discoloration (brown and yellow) -Stress (regurgitation) -Decomposition (liquification) -Lethargy (slow-moving to no movement at all. Refusal to eat)

The virus enters the nucleus of infected cells, and reproduces until the cell is assimilated by the virus and produces crystals in the fluids of the host. These crystals will transfer the virus from one host to another.

The host will become visibly swollen with fluid containing the virus and will eventually die - turning black with decay.

Transmissibility
The virus is unable to affect humans in the way it affects insects as our cells are acid-based, when it requires an alkaline-based cell in order to replicate. It is possible for the virus crystals to enter human cells, but not replicate to the point of illness.

It is transferred from insect to insect through crystals in all of their bodily emissions. As the virus is in the crystal-like capsid, it requires to be broken down by the alkaline digestive system of the insects to be released.

Mortality in infected insects is nearly 100%

Bleach and ultra-violet light have been found to prove effective in killing the virus.

References:

http://www.bio.davidson.edu/.../virusstructure.html

http://www.geocities.com/rainforest/2153/np.html

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/viruses.html

http://www.answers.com/topic/nuclear-polyhedrosis-virus?cat=technology

"The Cobra Event" - Richard Preston