Experimental transmission of Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) in Macrobrachium malcolmsonii and Macrobrachium rude

摘要

The susceptibility of two species of freshwater prawn, Macrobrachium malcolmsonii (17.7 +/- A 1.85 g, 9.5 +/- A 0.50 cm) and Macrobrachium rude (4.14 +/- A 0.95 g, 4.1 +/- A 0.56 cm), to Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) was tested. These two species were artificially infected with MrNV and XSV by oral and intramuscular routes using viral inoculum prepared from white tail disease-infected post-larvae of M. rosenbergii. No mortality or clinical symptoms were observed in the experimentally infected M. rude and M. malcolmsonii. The data of experimental infection indicate that MrNV and XSV failed to cause the mortality in these two species of freshwater prawn. But RT-PCR analysis of different organs of experimentally infected prawns showed the presence of MrNV and XSV in all the organs analyzed. Further, the viral inoculum prepared from experimentally infected M. malcolmsonii and M. rude caused 100 % mortality in post-larvae of M. rosenbergii (43.0 +/- A 2 mg, 1.34 +/- A 0.01 cm, PL stage 10). These results indicate the possibility of M. malcolmsonii and M. rude acting as reservoir for MrNV and XSV and maintaining their virulence in their tissues.