Taura syndrome virus from Belize represents a unique variant

Abstract

A Taura syndrome virus (TSV) isolate from cultured Penaeus vannamei grown in Belize, Central America was characterized and shown to be a unique isolate. Mortality rates in laboratory infections of specific pathogen-free (SPF) P. vannamei, reactivity of the virus with monoclonal antibody (MAb) 1A1 and phylogenetic analysis demonstrated that the Belize isolate (BLZ02TSV) is a new variant of TSV. The Hawaiian 1994 TSV isolate (HI94TSV, GenBank AF277675) was used as the reference isolate for these studies. Laboratory infections of SPF P. vannamei with BLZ02TSV demonstrated higher mortalities and earlier onset of mortalities compared to infections with HI94TSV. Shrimp tissues infected with BLZ02TSV reacted with a TSV-specific gene probe by in situ hybridization and were positive by RT-PCR using TSV diagnostic primers, thus indicating that the isolate was TSV. However, Western blot analysis and immunohistochemistry using MAb 1A1 demonstrated that BLZ02TSV did not react with the antibody, suggestive of changes in the VP1 region of the genome that codes for the polypeptide to which MAb 1A1 binds. Phylogenetic analysis of a 1.3 kbp fragment of the TSV VP1 capsid region revealed that BLZ02TSV represents a distinct group among more than 29 isolates of TSV studied thus far. This research demonstrates that BLZ02TSV is a unique isolate of TSV and reiterates a problem related to the use of MAb 1A1 for detection of TSV in clinical specimens. KEY WORDS: Taura syndrome virus · Belize · Monoclonal antibody 1A1Resale or republication not permitted without written consent of the publisher

Comparison of four Taura syndrome virus (TSV) isolates in oral challenge studies with Litopenaeus vannamei unselected or selected for resistance to TSV

“…1C). Our results were also consistent with Bz01 being more virulent than UsHi94 (Erickson et al 2005. The data in Fig.…”

“…For instance, Erickson et al (2005) demonstrated that Pacific white shrimp Litopenaeus vannamei (also called Penaeus vannamei) (Farfante & Kensley 1997) experimentally infected with a Belize isolate (Bz02) showed higher mortality than they did when infected with a Hawaiian isolate (UsHi94) (referred to as BLZ02TSV and Hi94TSV, respectively, in the cited paper). Phylogenetic analysis revealed that Bz02 was distinct among 29 isolates of TSV, despite the fact that TSV displays low genetic variation from 0 to 5.6% in nucleotide sequence and from 0 to 7% in deduced amino acid sequence ).…”

Characterization of a new strain of Taura syndrome virus (TSV) from Colombian shrimp farms and the implication in the selection of TSV resistant lines

“…In previous challenge tests at UA-APL, the final survival of the SPF line infected with TSV HW 94 was about 20-30% (Tang et al, 2004;Erickson et al, 2005;Srisuvan et al, 2006). However, in recent TSV challenge tests, including the one presented here, final survivals have been lower.…”

Taura syndrome virus in specific pathogen-free Penaeus vannamei originating from Hawaii and in P. vannamei stocks farmed in France?

“…2 as 'HI94TSV.' The references listed with the GenBank accession numbers for the sequence information for 'Hawaiian' and 'French' TSV isolates used by the authors in their analysis clearly indicate that AF510518 (Erickson et al 2005) is a 1164 bp portion of the TSV VP1. This sequence is 100% identical to the sequence for VP1 within the entire TSV genome sequence given by Mari et al (2002) in AF277675.…”