Infectious hypodermal and hematopoietic necrosis virus Infectious hypodermal and hematopoietic necrosis (IHHN) is a parvoviral disease of penaeid shrimp that causes mass mortality (up to 90%) among the Western blue shrimp (Penaeus stylirostris) and severe deformations in the Pacific white shrimp (P. vannamei).

The shrimp-farming industry has developed several broodstocks of both P. stylirostris and P. vannamei that are resistant against IHHN infection.

[2] This virus has been classified as Penaeus stylirostris hamaparvovirus.

NSI appears to be a DNA helicase with ATPase activity.

It is also similar to the rate found in other single stranded DNA viruses.