High efficacy of white spot syndrome virus replication in tissues of freshwater rice-field crab, Paratelphusa hydrodomous (Herbst)

An attempt was made to determine the replication efficiency of white spot syndrome virus (WSSV) of shrimp in different organs of freshwater rice-field crab, Paratelphusa hydrodomous (Herbst), using bioassay, PCR, RT-PCR, ELISA, Western blot and real-time PCR analyses, and also to use this crab instead of penaeid shrimp for the large-scale production of WSSV. This crab was found to be highly susceptible to WSSV by intramuscular injection. PCR and Western blot analyses confirmed the systemic WSSV infection in freshwater crab. The RT-PCR analysis revealed the expression of VP28 gene in different organs of infected crab. The indirect ELISA was used to quantify the VP28 protein in different organs of crab. It was found that there was a high concentration of VP28 protein in gill tissue, muscle, haemolymph and heart tissue. The copy number of WSSV in different organs of infected crab was quantified by real-time PCR, and the results revealed a steady increase in copy number in different organs of infected crab during the course of infection. The viral inoculum prepared from different organs of infected crab caused significant mortality in tiger prawn, Penaeus monodon (Fabricius). The results revealed that this crab can be used as an alternate host for WSSV replication and production.