Infeksi buatan white spot syndrome virus (WSSV) dan variasi genotipe lobster air tawar (Cherax quadricarinatus)

Abstract

Viruses are very abundant in sea water and therefore diseases caused by viruses are common in marine organisms. Viral diseases create major problem for the commercial farming of crustaceans. One of the most common and most devastating viral pathogen threatening the shrimp farming industry is White Spot Syndrome Virus (WSSV), which is spreading around the world and also infecting many different species of crustaceans including unnatural host as freshwater crayfish. Redclaw, like other invertebrates, rely instead on innate immune responses, which is mediated by haemocytes and that mechanisms are very efficient and complex. The infecti vity of white spot syndrome virus (WSSV) to redclaw (Cherax quadricarinatus) was artificially tested by immersion challenge and intramuscular injection along with hemogram analysis. The redclaw was found to be susceptible to White Spot Syndrome Virus (WSSV). The immersion method have the same impact as effective as intramuscular injection. Histopathological observations of various tissues of WSSV­infected redclaw showed similar symptoms to those from WSSV-infected penaeid shrimp. When redclaw still alive, the virus inclusion body only appearance in hepatopancreatocytes. For 24 h incubation period, the number of granulocytes by intramuscular injection was significantly higher than by immersion method as great as 58.08% and 43.31 % respectively. On the contrary, the number of hyalinocytes by immersion method was significantly higher than by intramuscular injection as big as 53.45% and 38.75%, respectively. These results indicate that WSSV has a significant effect to the population of redclaw haemocytes, where granulocytes are more resistant to and may interact by some means with the virus. Prawn Infective Doseso (PIDso) to kill 50% of the challenge redclaw was found on 10-2 virus fold dilution. DNA analysis with RFLP-mtDNA using HaeIII, Hind6I, HindlII, Rsal and Sacll restriction enzyme did not show genotype difference between the live and the dead ones.