title: Pre-exposure to infectious hypodermal and haematopoietic necrosis virus or to inactivated white spot syndrome virus (WSSV) confers protection against WSSV in Penaeus vannamei (Boone) post-larvae.
abstract: Larvae and post-larvae of Penaeus vannamei (Boone) were submitted to primary challenge with infectious hypodermal and haematopoietic necrosis virus (IHHNV) or formalin-inactivated white spot syndrome virus (WSSV). Survival rate and viral load were evaluated after secondary per os challenge with WSSV at post-larval stage 45 (PL45). Only shrimp treated with inactivated WSSV at PL35 or with IHHNV infection at nauplius 5, zoea 1 and PL22 were alive (4.7% and 4%, respectively) at 10 days post-infection (p.i.). Moreover, at 9 days p.i. there was 100% mortality in all remaining treatments, while there was 94% mortality in shrimp treated with inactivated WSSV at PL35 and 95% mortality in shrimp previously treated with IHHNV at N5, Z1 and PL22. Based on viral genome copy quantification by real-time PCR, surviving shrimp previously challenged with IHHNV at PL22 contained the lowest load of WSSV (0-1x10(3) copies microg-1 of DNA). In addition, surviving shrimp previously exposed to inactivated WSSV at PL35 also contained few WSSV (0-2x10(3) copies microg-1 of DNA). Consequently, pre-exposure to either IHHNV or inactivated WSSV resulted in slower WSSV replication and delayed mortality. This evidence suggests a protective role of IHHNV as an interfering virus, while protection obtained by inactivated WSSV might result from non-specific antiviral immune response.
authors.affiliation: Fundación CENAIM-ESPOL, Guayaquil, Ecuador.
authors.forename: J
authors.initials: J
authors.lastname: Melena
authors.forename: B
authors.initials: B
authors.lastname: Bayot
authors.forename: I
authors.initials: I
authors.lastname: Betancourt
authors.forename: Y
authors.initials: Y
authors.lastname: Amano
authors.forename: F
authors.initials: F
authors.lastname: Panchana
authors.forename: V
authors.initials: V
authors.lastname: Alday
authors.forename: J
authors.initials: J
authors.lastname: Calderón
authors.forename: S
authors.initials: S
authors.lastname: Stern
authors.forename: Ph
authors.initials: P
authors.lastname: Roch
authors.forename: J-R
authors.initials: JR
authors.lastname: Bonami
mesh_terms: D000818:Animals; D017756:Aquaculture; D019223:Densovirinae / Q000276:immunology*; D007814:Larva / Q000821:virology; D033561:Penaeidae / Q000276:immunology / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016019:Survival Analysis; D013997:Time Factors; D019562:Viral Load / Q000662:veterinary; D038301:Virus Inactivation; D046848:White spot syndrome virus 1 / Q000276:immunology*