Infectious hypodermal and hematopoietic necrosis (IHHN) is a viral disease of

penaeid shrimp Penaeidae is a family of marine crustaceans in the suborder Dendrobranchiata, which are often referred to as penaeid shrimp or penaeid prawns. The Penaeidae contain many species of economic importance, such as the tiger prawn, whiteleg shrimp, ...

that causes mass mortality (up to 90%) among the Western blue shrimp (''

Penaeus stylirostris ''Penaeus'' is a genus of prawns, including the giant tiger prawn (''P. monodon''), the most important species of farmed crustacean worldwide. The genus has been reorganised following a proposition of Pérez Farfante and Kensley based on morph ...

'') and severe deformations in the Pacific white shrimp ('' P. vannamei''). It occurs in Pacific farmed and wild shrimp, but not in wild shrimp on the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

coast of the Americas. The shrimp-farming industry has developed several broodstocks of both ''P. stylirostris'' and ''P. vannamei'' that are resistant against IHHN infection. The disease is caused by a single-stranded

DNA virus A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and ...

of the species ''Decapod pestylhamaparvovirus 1'', earlier known as IHHN virus, the smallest of the known penaeid shrimp viruses (22 nm).Gulf States Marine Fisheries Commission
''Non-Native Species Summaries: ''Infectious Hypodermal and Hematopoietic Necrosis Virus'' (IHHNV)''
, 2003. Accessed June 30, 2005.

Virology

This virus has been classified as Penaeus stylirostris hamaparvovirus. The genome is 4.1 kilobases in length. There are three open reading frames in its genome:Rai P, Safeena MP, Karunasagar I, Karunasagar I (2011) Complete nucleic acid sequence of ''Penaeus stylirostris'' hamaparvovirus (PstDNV) from India. Virus Res 158(1-2):37-45 a left non structural protein (NS1) of 2001 base pairs (bp), a mid non structural protein (NS2) of 1092 bp and a right capsid protein of 990 bp. NSI appears to be a DNA helicase with ATPase activity. The mutation rate in the genome has been estimated to be ~1.4 x 10⁻⁴ substitutions/site/year.Robles-Sikisaka R, Bohonak AJ, McClenaghan LR Jr, Dhar AK (2010) Genetic signature of rapid IHHNV (infectious hypodermal and hematopoietic necrosis virus) expansion in wild Penaeus shrimp populations. PLoS One 5(7):e11799
Link
/ref> This is considerably higher than the rate in the double stranded DNA viruses and similar to that found in RNA viruses. It is also similar to the rate found in other single stranded DNA viruses.

References

External links

Viral zon

Penaeidae Animal viral diseases Diseases and parasites of crustaceans {{Veterinary-med-stub