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November 21, 2015


Loop Mediated Diagnostic Kit for WSSV


Loop mediated isothermal amplification (LAMP) is a DNA amplification technique that can amplify DNA in isothermal (constant temperature) conditions.  Unlike polymerase chain reaction (PCR) methods, which amplify DNA by constantly changing temperatures, the LAMP assay uses a single temperature.


A LAMP-based, on-site, diagnostic kit for the rapid detection of whitespot syndrome virus (WSSV) has been developed by a team of researchers at the University of Santo Tomas in Manila, Philippines.  It can amplify the target gene of the pathogen using a single temperature, with results in one hour.  The kit is designed to replace the traditional practice of relying on on-site morphological and physiological observations to determine the occurrence of disease.  The kit includes a locally fabricated heat block that replaces expensive commercially available equipment.  This heat block uses low-cost raw materials that deliver the right balance of effectiveness and simplicity needed in a farm setting.  It also includes a sample preparation kit for the LAMP reaction that can extract DNA from the target organ in less than 20 minutes.  The reagents used in the kit are all inexpensive and readily available.  The kit also uses a simple dye that can be seen under black light to interpret the test results.  It eliminates expensive equipment, tedious sample preparation and the visualization of results associated with conventional PCR assays.


The diagnostic kit was conceived for farm-based detection.  During its pilot testing at selected sites in the Philippines, there were no false positive results, and the DNA isolation part of the kit provided validated DNA.  The kit also proved more sensitive than PCR in the farm setting.  Using the prototype kit, 87% of the samples tested positive, while PCR testing identified only 25% positives from the same samples.  The farm personnel performed the procedure with the help of a simple manual and minimal training.  They were able to extract the DNA, perform the assay and view results using a hand-held black light.


Information: Mary Beth B. Maningas, Research Center, Department of Biological Science, College of Science, University of Santo Tomas, Manila, Philippines (email


Source: The Global Aquaculture Advocate (The Global Magazine for Farmed Seafood).  Editor, Darryl Jory (  Innovation: From Bench to Farm/Innovative On-Site Diagnostic Kit Identifies WSSV in Shrimp.  Mary Beth B. Maningas, Joselito A. Tabardillo, Jr., and Christopher Marlowe Caipang.  Volume 18, Issue 6, Page 64, November/December 2015.

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