Wang C S, Chang J S, Shih H H, Chen S N
Department of Life Science, National University of Kaohsiung, Kaohsiung, Taiwan.
J Fish Dis. 2007 Mar;30(3):127-32. doi: 10.1111/j.1365-2761.2007.00793.x.
Post-larvae of Macrobrachium rosenbergii infected with white tail disease (WTD) have been reported in Taiwan. The causative agents have been identified as M. rosenbergii nodavirus (MrNV) associated with extra small virus (XSV). The present study is the first report confirming the presence of XSV virus in M. rosenbergii displaying WTD symptoms in Taiwan by reverse transcription polymerase chain reaction (RT-PCR). A 772 bp amplified product was obtained by RT-PCR, cloned and sequenced. The nucleotide sequence analysis of the 772 bp DNA fragment revealed 98% and 97% identity with XSV isolated from China and India, respectively. Comparison of the deduced amino acid sequences of the XSV partial genome showed strong homology (99% and 97%) with isolates from China and India. Phylogenetic analysis revealed the XSV-Taiwan isolate was more closely related to the Chinese rather than the Indian isolates. The results demonstrated the presence of XSV virus co-infection in M. rosenbergii cultured in Taiwan suffering from WTD.
台湾已报道感染白尾病（WTD）的罗氏沼虾后期幼体。病原体已被鉴定为与超小病毒（XSV）相关的罗氏沼虾诺达病毒（MrNV）。本研究是首次通过逆转录聚合酶链反应（RT-PCR）证实台湾出现白尾病症状的罗氏沼虾中存在XSV病毒的报告。通过RT-PCR获得了一个772 bp的扩增产物，进行克隆和测序。对772 bp DNA片段的核苷酸序列分析显示，与从中国和印度分离的XSV分别有98%和97%的同一性。XSV部分基因组推导氨基酸序列的比较显示，与来自中国和印度的分离株有很强的同源性（99%和97%）。系统发育分析表明，台湾分离的XSV与中国分离株的关系比与印度分离株的关系更密切。结果表明，在台湾养殖的患白尾病的罗氏沼虾中存在XSV病毒共感染。
