Natural and experimental infection of white spot syndrome virus (WSSV) in benthic larvae of mud crab Scylla serrata

White spot syndrome virus (WSSV), the causative agent of white spot syndrom e in shrimp, has a wide host range which extends to crabs, copepods and oth er arthropods. In this study, benthic larvae of the mud crab Scylla serrata were captured from Taiwan's coastal waters and screened for the presence o f WSSV by polymerase chain reaction (PCR) and in situ hybridization. WSSV w as detected in around 60% of the larvae, and this prevalence rate remained fairly constant when the captured larvae were subsequently maintained in an aerated system in the laboratory. WSSV-free larvae obtained from a hatcher y were challenged by immersion in a WSSV inoculum. Fifteen days after chall enge, cumulative mortality in the experimental group reached 43% compared t o 20% in the control group. PCR detection of WSSV in both moribund and surv iving specimens clearly implicated the virus as the cause of death in most cases. Histological and in situ hybridization data confirmed that WSSV tiss ue tropism in Scylla serrata crab larvae is similar to that found in shrimp .