Macronovirus

The genus name, Macronovirus, is a combination of Macro, from the host Macrobrachium rosenbergii and no, from helper virus nodavirus. == Hosts ==

Macronovirus's cell tropism is muscle and connective cells of diseased animals, and its natural hosts are arthropods. == Structure ==

The virion of XSV has a genome consisting of linear single-stranded RNA of positive polarity, 0.8kb in size, with two genes. This encodes two capsid proteins, CP-17 and CP-16. The virion is non-enveloped, spherical, with a capsid of about 15 nm with icosahedral symmetry. The virion is constructed from two capsid proteins CP-17 and CP-16. It has a Monopartite, linear, ssRNA(+) genome. == Gene expression ==

The virion RNA is infectious and serves as both the genome and viral messenger RNA. == Replication ==

Its replication is cytoplasmic, and has 8 steps. • Attachement to host receptors mediates entry into the host cell. • Uncoating, and release of the viral genomic RNA into the cytoplasm. • Viral RNA is translated in a polyprotein to produce replication proteins. • Replication by helper virus occurs in viral factories made of membrane vesicles derived from the ER. A dsRNA genome is synthesized from the genomic ssRNA(+). • The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes. • Expression of the capsid proteins. • Assembly of new virus particles. • Virus release. == Disease ==

Whitish muscle disease, which develops in post-larvae of freshwater prawn Macrobrachium rosenbergii and is caused by Macrobrachium rosenbergii nodavirus (MrNV) and its associate Extra small virus. Main symptom is a whitish appearance of the muscles, particularly noticeable in the abdomen. Mortalities can reach 100%. ==References==