Determination of the Infectious Agent of Translucent Post-Larva Disease (TPD) in Penaeus vannamei

Abstract

A new emerging disease called “translucent post-larvae disease” (TPD) or “glass post-larvae disease” (GPD) of Penaeus vannamei, characterized by pale or colorless hepatopancreas and digestive tract, has become an urgent threat to the shrimp farming industry. Following this clue that treatment of an antibacterial agent could alleviate the disease, systematic investigation of the potential infectious agent of TPD was conducted using bacterial identification and artificial challenge tests to fulfill Koch’s postulates. A dominant bacterial isolate, Vp-JS20200428004-2, from the moribund individuals was isolated and identified as Vibrio parahaemolyticus based on multi-locus sequence analysis. However, Vp-JS20200428004-2 differed from the V. parahaemolyticus that caused typical acute hepatopancreatic necrosis disease. Immersion challenge tests revealed that Vp-JS20200428004-2 could cause 100% mortality within 40 h at a dose of 1.83 × 106 CFU/mL, and experimental infected shrimp showed similar clinical signs of TPD. The Vp-JS20200428004-2 could be re-isolated and identified from the experimental infected individuals. Moreover, histopathological analysis of diseased samples indicated that Vp-JS20200428004-2 caused severe necrosis and sloughing of epithelial cells of the hepatopancreas and midgut in shrimp individuals both naturally and experimentally infected. Our present results indicated that Vp-JS20200428004-2 is a highly virulent infectious agent associated with the TPD and deserves further attention.

Complete genome sequence of highly pathogenic Vibrio parahaemolyticus isolated from mariculture Penaeus vannamei reveals virulence factor genes

“…Its pathogenicity is usually determined by the interaction between the bacterium and the host cell. The prediction of virulence genes and the genetic analyses of bacterial virulence factors showed that pathogens are distinguished from their non‐pathogenic relatives by the presence of specific pathogenicity genes (Han, Tang, & Lightner 2015; Zou et al., 2020). In the normal PCR, virulence genes (pirA and pirB) of the isolated bacteria were confirmed existence.…”

The transcriptome of Litopenaeus vannamei in zoea larvae and adults infected by Vibrio parahaemolyticus

“…Infection with Vibrio parahaemolyticus in the early stages of shrimp, particularly the Zoea stage, often results in huge death of larvae (Angthong et al, 2021). In China, an unique illness known as "translucent postlarvae disease" (TPD) or "glass post-larvae disease" (GPD) caused by highly pathogenic vibrios with virulence has lately caused significant economic losses (Zou et al, 2020).…”

Characterization of a novel shrimp pathogen, Vibrio brasiliensis, isolated from Pacific white shrimp, Penaeus vannamei

“…Among various kinds of pathogens, Vibrio is considered as one of the most important hazards for shrimp culturing (Flegel, 2012;Ina-Salwany et al, 2019;Thitamadee et al, 2016). Many Vibrio species have been reported to be virulent to shrimp, for example V. harveyi (Rungrassamee et al, 2016;Soto-Rodriguez et al, 2012), V. alginolyticus (Lee et al, 1996;Selvin & Lipton, 2003;Vandenberghe et al, 1999), V. parahaemolyticus (Ananda Raja et al, 2017;Jia et al, 2018;Tran et al, 2013;Zhang et al, 2012;Zou et al, 2020), V. campbellii (Dong et al, 2017;Soto-Rodríguez et al, 2006), V. rotiferianus (Zhang et al, 2014), V. cholerae (Joseph et al, 2015), V. nigripulchritudo (Goarant & Merien, 2006;Walling et al, 2010) and V. penaecida Maningas et al, 2008).…”