White spot syndrome virus (WSSV) is the most serious and important disease threatening in the shrimp farming industry in Vietnam and over the world. In this study, by using the PCR technique, the authors detected WSSV persisting in the pond sediment
plankton and other crustacean samples that are collected in some main shrimping and large abandon areas causing by WSSV in Vietnam. The samples are taken in shrimp pond and surrounding canals that are used as water input and output for the ponds. A result is 43/60 samples of plankton, 47/60 samples of pond sediment and 38/60 sample of other crustacean detected positive with WSSV. The highest rates of sample that positive with WSSV belong to abandon ponds and canals causing by WSSV.