October 15, 2010

Thai researchers develop virus detector for shrimp

Researchers in Thailand have created a tool to detect a virus pest that is guilty of spurring mass economic losses there and in other major shrimp-producing countries.

The device is able to detect the presence of any shrimp virus within 30 minutes.

The Real-time Turbidimeter for Shrimp Virus Detection was developed through a joint effort called the loop-mediated isothermal amplification reaction (Lamp) project, involving the National Electronic and Computer Technology Centre (Nectec) and the National Centre for Genetic Engineering and Biotechnology (Biotec).

Nectec researcher and project leader Adisorn Tuantranont said the team sought to slash the cost of importing foreign technology, and achieved its goal after about two years.

A novel method of gene amplification, Lamp works on nucleic acid and can be used to diagnose disease in shrimp farms. A reaction using the device will show a white precipitate of magnesium pyrophosphate in correlation with the amount of synthesised DNA, signifying that the shrimp contains a virus. A real-time turbidimeter then measures the turbidity of the water.

The turbidimeter integrates a heating block that keeps the temperature at an optimal 63 C for the duration of a test on a shrimp sample measuring just 25 millionths of a litre and conducted in a 0.2-ml tube.

The sample's white turbidity can be observed in real time as light from an economical light-emitting diode travels through the tube. A spectroscopic measuring method then evaluates the Lamp reaction's by-products. Real-time monitoring software has also been created to give measurements in the form of a line graph.

According to Tuantranont, the new system offered a relatively short analysis time, low cost and no need for a thermocycler, detection reagents, or opening the reaction tube.

The system can be implemented for the screening and confirmatory diagnosis of shrimp virus, and is also recommended by Tuantranout for use in shrimp-health management schemes for disease control in hatcheries and grow-out ponds.

Nectec is now holding talks with a private-sector firm on the transfer of technology so new products can be developed to assist the local shrimp aquaculture sector, Tuantranout said.