The prevalence of covert mortality nodavirus (CMNV) has become one of the major threats to the shrimp farming industry in Asia and South America recently. Here, the genomic RNA1 and RNA2 of CMNV were characterized by using transcriptome sequencing and RT-PCR. Our study revealed that RNA1 is 3228 bp in length, and contains two putative Open Reading Frames (ORFs), one encoding the RNA dependent RNA polymerase (RdRp) of length 1043 amino acids and another encoding the protein B2 with a length of 132 amino acids. RNA2 is 1448 bp in length and encodes a capsid protein of 437 amino acids. CMNV shared the highest similarity of 51.78 % for RdRp with the other known nodaviruses. Phylogenetic analyses on the basis of RdRp, B2 and capsid proteins indicated that CMNV might represent a novel viral species in the family Nodaviridae. This study reported the first genome sequence of CMNV and it would be helpful for further studies of CMNV in relation to its evolution, diagnostic technique and control strategy.

隐性死亡诺达病毒（CMNV）的流行已成为亚洲和南美最近对虾养殖业的主要威胁之一。在这里，CMNV的基因组RNA1和RNA2使用转录组测序和RT-PCR进行了表征。我们的研究表明，RNA1的长度为3228 bp，包含两个推定的开放阅读框（ORF），一个编码长度为1043个氨基酸的RNA依赖性RNA聚合酶（RdRp），另一个编码长度为132个氨基酸的B2蛋白。 。RNA2的长度为1448 bp，编码一个437个氨基酸的衣壳蛋白。CMNV与其他已知的诺达病毒在RdRp中的相似性最高，为51.78％。的RdRp的基础上系统发生分析，B2和衣壳蛋白表明CMNV可能代表在家庭的新型病毒种类野田病毒科。这项研究报告了CMNV的第一个基因组序列，这将有助于进一步研究CMNV的进化，诊断技术和控制策略。