Development of a duplex PCR as screening tool for the detection of Crangon crangon bacilliform virus in the European brown shrimp Crangon crangon

The brown shrimp Crangon crangon is an important species ecologically and economically. Due to low landings of large animals (less than 2 % > 7cm) and a growing demand for living shrimps, C. crangon was identified as a candidate for aquaculture. However, in 2004, researchers found thatthis species could be infected with C. Crangon Bacilliform Virus, an intranuclear bacilliform virus mainly infecting the hepatopancreas. This virus,acting as an extra stress factor, could affect the health status of C. crangon reared in captivity, resulting in higher mortality. CCBV could therefore bethe reason why the life cycle of C. crangon was never closed in captivity. A screening tool for the detection of CCBV was developed in order toexamine the infection severity. The research focused on the optimization of a duplex PCR, which amplifies an internal amplification control geneand a viral gene. Once the duplex PCR was optimized with reared shrimp, a prevalence study was conducted with wild samples from several regionsof the Belgian Coast. Results indicate that the prevalence of CCBV is between 80 and 94 % in the examined populations. The high prevalence canindicate that the virus is transmitted from female to offspring. To confirm this hypothesis, more experiments are needed to determine how thisvirus is transmitted to the offspring. The development of a detection tool for CCBV offers the ability to rapidly and reliably screen wild and reared C.crangon and also transmission can be studied in more detail. This will enable us to select healthy and virus-free individuals, which will not onlycontribute to the rearing of this species, but also for research purposes, allowing us to use standardized bioassay tests.