A Novel RNA Virus, Macrobrachium rosenbergii Golda Virus (MrGV), Linked to Mass Mortalities of the Larval Giant Freshwater Prawn in Bangladesh

• Published in: Viruses 2020-10, Vol.12 (10), p.1120
• Main Authors: Hooper, Chantelle, Debnath, Partho P, Biswas, Sukumar, van Aerle, Ronny, Bateman, Kelly S, Basak, Siddhawartha K, Rahman, Muhammad M, Mohan, Chadag V, Islam, H M Rakibul, Ross, Stuart, Stentiford, Grant D, Currie, David, Bass, David
• Format: Article
• Language: English
• Subjects: Animals; Aquaculture; Bangladesh - epidemiology; Disease; Environmental impact; Experiments; Fish hatcheries; Fresh Water - virology; freshwater prawns; Hatcheries; Larva - virology; Larvae; Macrobrachium rosenbergii; Macrobrachium rosenbergii Golda virus; New species; Nidovirales; Nodaviridae - genetics; Nodaviridae - isolation & purification; Open Reading Frames; Palaemonidae - virology; Pathogens; Phylogeny; Rivers; RNA virus; RNA Virus Infections - mortality; RNA Virus Infections - veterinary; RNA viruses; RNA Viruses - classification; RNA Viruses - genetics; RNA Viruses - isolation & purification; Roniviridae; Sequence Alignment; Viruses
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v12101120

Mass mortalities of the larval stage of the giant freshwater prawn, , have been occurring in Bangladesh since 2011. Mortalities can reach 100% and have resulted in an 80% decline in the number of hatcheries actively producing . To investigate a causative agent for the mortalities, a disease challenge was carried out using infected material from a hatchery experiencing mortalities. Moribund larvae from the challenge were prepared for metatranscriptomic sequencing. virus assembly revealed a 29 kb single‑stranded positive-sense RNA virus with similarities in key protein motif sequences to yellow head virus (YHV), an RNA virus that causes mass mortalities in marine shrimp aquaculture, and other viruses in the order. Primers were designed against the novel virus and used to screen cDNA from larvae sampled from hatcheries in the South of Bangladesh from two consecutive years. Larvae from all hatcheries screened from both years were positive by PCR for the novel virus, including larvae from a hatchery that at the point of sampling appeared healthy, but later experienced mortalities. These screens suggest that the virus is widespread in hatchery culture in southern Bangladesh, and that early detection of the virus can be achieved by PCR. The hypothesised protein motifs of Macrobrachium rosenbergii golda virus (MrGV) suggest that it is likely to be a new species within the order. Biosecurity measures should be taken in order to mitigate global spread through the movement of post-larvae within and between countries, which has previously been linked to other virus outbreaks in crustacean aquaculture.