title: Quantitative relationship of two viruses (MrNV and XSV) in white-tail disease of Macrobrachium rosenbergii.
abstract: Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) were purified from diseased freshwater prawns M. rosenbergii and used to infect healthy post-larvae (PL) by an immersion method. Three groups of prawns were challenged with various combined doses of MrNV and XSV. Signs of white-tail disease (WTD) were observed in Groups 1 and 2, which had been challenged with combinations containing relatively high proportions of MrNV and low proportions of XSV. By contrast there was little sign of WTD in Group 3, which had been challenged with a higher proportion of XSV than MrNV. A 2-step Taqman real-time RT-PCR was developed and applied to quantify viral copy numbers in each challenged PL. Results showed that genomic copies of both viruses were much higher in Groups 1 and 2 than they were in Group 3, indicating that MrNV plays a key role in WTD of M. rosenbergii. The linear correlation between MrNV and XSV genome copies in infected prawns demonstrated that XSV is a satellite virus, dependent on MrNV, but its role in pathogenicity of WTD remains unclear.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China.
authors.forename: Huajun
authors.initials: H
authors.lastname: Zhang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wang
authors.forename: Junfa
authors.initials: J
authors.lastname: Yuan
authors.forename: Lijuan
authors.initials: L
authors.lastname: Li
authors.forename: Jianhong
authors.initials: J
authors.lastname: Zhang
authors.forename: Jean-Robert
authors.initials: JR
authors.lastname: Bonami
authors.forename: Zhengli
authors.initials: Z
authors.lastname: Shi
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000737:chemistry; D046529:Microscopy, Electron, Transmission / Q000379:methods; D030381:Nodaviridae / Q000235:genetics / Q000472:pathogenicity*; D033541:Palaemonidae / Q000821:virology*; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D017931:DNA Primers; D012337:RNA, Ribosomal, 18S; D012367:RNA, Viral