Showing papers by "Donald V. Lightner published in 2013"
TL;DR: AHPNS has a bacterial etiology and Koch's Postulates have been satisfied in laboratory challenge studies with the isolate, which has been identified as a member of the Vibrio harveyi clade, most closely related to V. parahemolyticus.
Abstract: A new emerging disease in shrimp, first reported in 2009, was initially named early mortality syndrome (EMS). In 2011, a more descriptive name for the acute phase of the disease was proposed as acute hepatopancreatic necrosis syndrome (AHPNS). Affecting both Pacific white shrimp Penaeus vannamei and black tiger shrimp P. monodon, the disease has caused sig- nificant losses in Southeast Asian shrimp farms. AHPNS was first classified as idiopathic because no specific causative agent had been identified. However, in early 2013, the Aquaculture Pathol- ogy Laboratory at the University of Arizona was able to isolate the causative agent of AHPNS in pure culture. Immersion challenge tests were employed for infectivity studies, which induced 100% mortality with typical AHPNS pathology to experimental shrimp exposed to the pathogenic agent. Subsequent histological analyses showed that AHPNS lesions were experimentally in - duced in the laboratory and were identical to those found in AHPNS-infected shrimp samples col- lected from the endemic areas. Bacterial isolation from the experimentally infected shrimp enabled recovery of the same bacterial colony type found in field samples. In 3 separate immer- sion tests, using the recovered isolate from the AHPNS-positive shrimp, the same AHPNS pathol- ogy was reproduced in experimental shrimp with consistent results. Hence, AHPNS has a bacter- ial etiology and Koch's Postulates have been satisfied in laboratory challenge studies with the isolate, which has been identified as a member of the Vibrio harveyi clade, most closely related to V. parahemolyticus.
666 citations
TL;DR: The bacteria that cause necrotizing hepatopancreatitis in Penaeus vannamei adversely affect penaeid shrimp cultured in the western hemisphere and the name “Candidatus Hepatobacter penaei” is proposed for these pathogenic bacteria.
Abstract: The bacteria that cause necrotizing hepatopancreatitis in Penaeus vannamei adversely affect penaeid shrimp cultured in the western hemisphere. 16S rRNA and gyrase B gene analyses determined the taxonomic position of these bacteria. The name "Candidatus Hepatobacter penaei" is proposed for these pathogenic bacteria, which are members of the Rickettsiales order.
29 citations
TL;DR: This study suggests that the TSV present in Colombian shrimp farms during the last 5 years is a new TSV strain with high virulence.
22 citations
TL;DR: 4 WSSV genotypes were detected, which were characterized by a full-length deletion in ORF94/95, a relatively small ORF75 and one specific deletion length in each variable region, which suggests that the W SSV epidemics in these 3 countries were from a common source, possibly the environment.
Abstract: White spot syndrome virus (WSSV) is highly pathogenic to penaeid shrimp and has caused significant economic losses in the aquaculture industry around the world. During 2010 to 2012, WSSV caused severe mortalities in cultured penaeid shrimp in Saudi Arabia, Mozambique and Madagascar. To investigate the origins of these WSSV, we performed genotyping analyses at 5 loci: the 3 open reading frames (ORFs) 125, 94 and 75, each containing a variable number of tan- dem repeats (VNTR), and deletions in the 2 variable regions, VR14/15 and VR23/24. We catego- rized the WSSV genotype as {N125, N94, N75, ΔX14/15, ΔX23/24} where N is the number of repeat units in a specific ORF and ΔX is the length (base pair) of deletion within the variable region. We detected 4 WSSV genotypes, which were characterized by a full-length deletion in ORF94/95, a relatively small ORF75 and one specific deletion length in each variable region. There are 2 closely related genotypes in these 3 countries: {6125, del94, 375, Δ595014/15, Δ1097123/24} and {7125, del94, 375, Δ595014/15, Δ1097123/24}, where del is the full-length ORF deletion. In Saudi Arabia, 2 other related types of WSSV were also found: {6125, 794, 375, Δ595014/15, Δ1097123/24} and {8125, 1394, 375, Δ595014/15, Δ1097123/24}. The identical patterns of 3 loci in these 4 types indicate that they have a common lineage, and this suggests that the WSSV epidemics in these 3 countries were from a common source, possibly the environment.
19 citations
TL;DR: A WSSV variant in Penaeus indicus that heavily infects the subcuticular connective tissue, with very slight indications in the cuticular epithelium is discovered.
12 citations