Infectious hypodermal and hematopoietic necrosis virus (IHHNV), also known as Decapod Penstylhamaparvovirus 1, is a World Organisation for Animal Health (WOAH, Paris, France) listed pathogen. In the early 1980s, infection with IHHNV caused large-scale mortalities in blue shrimp (Penaeus stylirostris) in the Americas. In Pacific white shrimp (P. vannamei), the predominant farmed penaeid shrimp worldwide, IHHNV infection does not cause any mortality but results in growth retardation and deformities. The virus has been reported in all shrimp farming countries around the world. IHHNV is vertically transmitted and hence routine screening of broodstock and post larvae are critical to ensure specific pathogen free (SPF) status of a population.
IHHNV challenge experiments were performed simultaneously at the Aquaculture Pathology Laboratory (APL) at the University of Arizona and at the National Veterinary Services Laboratories (NVSL) using a single lot of Penaeus vannamei SPF shrimp. Infected shrimps were sacrificed over a 30-day period and archived at -80°C. Unchallenged SPF P. vannamei served as negative controls. Both IHHNV challenged and unchallenged animals from APL were sent to the NVSL, where duplicate samples containing gill and pereopod tissue from each animal were dissected and coded. The blinded panel was evaluated at both laboratories using TaqMan real-time PCR with newly developed IHHNV primer/probe sets (qIH-Fw and qIH-Rv/3072-IH-Probe, and 3144F and 3232R/ 3187-IH-Probe), and EF-1 internal control gene. We are currently comparing assay performance and reproducibility that are necessary for IHHNV screening.
Key words: Infectious hypodermal and hematopoietic necrosis virus, IHHNV, Shrimp, Penaeus vannamei.