Detection of Nodavirus associated with white tail disease in Macrobrachium rosenbergii by the RTPCR method in Malaysia

Objective: The objective of this project was to detect the gene suspected for causing nodavirus infection in the Malaysian giant fresh water prawn, using the RT-PCR method. Method & Materials: 1. Collection of sample (from ponds and rivers in Malaysia); 2. Total RNA extraction by TRIzol; 3. Reverse transcriptasepolymerase chain reaction (RT-PCR)=One step by kit; 4. Cloning; 5. Plasmid extraction; 6. Sequencing. Results & Conclusion:The giant prawn, Macrobrachium rosenbergii, is locally known in Malaysia as ‘Udang Galah'. Some wild stocks of M. rosenbergii have seen declined in recent years as they are threatened by diseases. Such declines have been recorded in Malaysia as a result of high mortality. Therefore, methods for the disease detection of this species are necessary. One of the new viral diseases in M. rosenbergii is white tail disease (WTD).White tail disease is found to cause immense economic losses in hatcheries and farms , with mortalities often reaching 100% within 2 or 3 days. A whitish appearance of the tail is the most prominent clinical sign and therefore, the disease is named as white tail disease. Two viruses, M. rosenbergii nodavirus (MrNV) and extra small virus (XSV) have been found to be responsible for white tail disease. Two amplified products, one 650 bp and the other 1114 bp were obtained by RT-PCR. The nucleotide sequences analysis of these two amplified segments showed nucleotide and amino acid sequence identity with the reported sequence of a MrNV isolate from Thailand. This is the first report on the occurrence of MrNV in WTD of the giant fresh water prawn from Malaysia.

کلیدواژه ها:

Macrobrachium rosenbergii nodavirus ، RT-PCR assay ، White tail disease ، XSV ، sequence analysis