Rahman M M, Corteel M, Escobedo-Bonilla C M, Wille M, Alday-Sanz V, Pensaert M B, Sorgeloos P, Nauwynck H J
Laboratory of Aquaculture & Artemia Reference Center, Faculty of Bioscience Engineering, Ghent University, Rozier 44, 9000 Ghent, Belgium.
Dis Aquat Organ. 2008 May 8;79(3):191-8. doi: 10.3354/dao01907.
A standardized inoculation model was used in 2 separate experiments to gauge the virulence of 3 white spot syndrome virus (WSSV) isolates from Thailand and Vietnam (WSSV Thai-1, WSSV Thai-2, and WSSV Viet) in Penaeus vannamei juveniles. Mortality patterns (Expt 1) were compared and WSSV-positive cells quantified (Expt 2) in tissues following intramuscular inoculation of shrimp with the most (WSSV Thai-1) and least (WSSV Viet) virulent isolates as determined by Expt 1. The results of Expt 1 demonstrated that mortalities began at 36 h post inoculation (hpi) for both Thai isolate groups and at 36 to 60 hpi for the Viet isolate group. Cumulative mortality reached 100% 96 to 240 h later in shrimp challenged with the WSSV Viet isolate compared to shrimp challenged with the Thai isolates. WSSV infection was verified in all groups by indirect immunofluorescence. In Expt 2, WSSV-infected cells were quantified by immunohistochemical analysis of both dead and time-course sampled shrimp. WSSV-positive cells were detected in tissues of Thai-1 inoculated dead and euthanized shrimp from 24 hpi onwards and from 36 hpi onwards in shrimp injected with the Viet isolate. Significantly more infected cells were found in tissues of dead shrimp inoculated with the Thai-1 than in Viet isolate-inoculated shrimp. In these experiments, substantial differences in virulence were demonstrated between the WSSV isolates. The Vietnamese isolate induced a more chronic disease and mortality pattern than was found for the Thai isolates, possibly because it infected fewer cells. This difference was most pronounced in gills.
在两项独立实验中使用了标准化接种模型，以评估来自泰国和越南的3种白斑综合征病毒（WSSV）分离株（WSSV Thai-1、WSSV Thai-2和WSSV Viet）对凡纳滨对虾幼体的毒力。在实验1中，对肌肉注射虾后组织中的死亡率模式进行了比较，并在实验2中对WSSV阳性细胞进行了定量，实验1确定了毒力最强（WSSV Thai-1）和最弱（WSSV Viet）的分离株。实验1的结果表明，两个泰国分离株组在接种后36小时开始出现死亡，越南分离株组在接种后36至60小时开始出现死亡。与感染泰国分离株的虾相比，感染WSSV Viet分离株的虾在96至240小时后累计死亡率达到100%。通过间接免疫荧光在所有组中均验证了WSSV感染。在实验2中，通过对死亡和随时间取样的虾进行免疫组织化学分析，对WSSV感染的细胞进行了定量。在接种泰国-1分离株的死亡和安乐死虾的组织中，从接种后24小时起检测到WSSV阳性细胞，在注射越南分离株的虾中，从接种后36小时起检测到WSSV阳性细胞。在接种泰国-1分离株的死亡虾组织中发现的感染细胞明显多于接种越南分离株的虾。在这些实验中，WSSV分离株之间表现出明显的毒力差异。越南分离株诱导的疾病和死亡率模式比泰国分离株更为慢性，可能是因为它感染的细胞较少。这种差异在鳃中最为明显。
