6 research outputs found

    Experimental infection of redclaw crayfish (Cherax quadricarinatus) with Macrobrachium rosenbergii nodavirus, the aetiological agent of white tail disease

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    Macrobrachium rosenbergii nodavirus (MrNV) or white tail disease has been reported as a new disease of crustacea in western Queensland, Australia. In Australia, Macrobrachium can be hard to source due to their need for a saltwater environment for breeding. No alternative animal experimental model for MrNV has been identified, so redclaw crayfish (Cherax quadricarinatus) were tested as a potential experimental animal in order to study MrNV infection. The highest mortality (35%) was in the groups injected with MrNV and the lowest mortality (0%) was in the control groups. Necrotic muscle and muscle degeneration with haemocytic infiltration were observed in infected crayfish. For the first time, a quantitative real-time polymerase chain reaction (qPCR) on clinical material was developed and it confirmed MrNV infection in infected animals. The mean viral titres (2.73 Ă— 102 copies) and cycle times (Ct = 31.33) lead us to hypothesize that MrNV only poorly replicates in juvenile C. quadricarinatus. However, C. quadricarinatus may be a less than perfect but useable experimental animal model for MrNV infection in the future because of clinical signs, gross lesions, histopathological changes and qPCR titres present in experimentally infected C. quadricarinatus. This study determined that redclaw crayfish (C. quadricarinatus) had low susceptibility and were limited carriers of white tail disease

    RNA interference with special reference to combating viruses of crustacea

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    RNA interference has evolved from being a nuisance biological phenomenon to a valuable research tool to determine gene function and as a therapeutic agent. Since pioneering observations regarding RNA interference were first reported in the 1990s from the nematode worm, plants and Drosophila, the RNAi phenomenon has since been reported in all eukaryotic organisms investigated from protozoans, plants, arthropods, fish and mammals. The design of RNAi therapeutics has progressed rapidly to designing dsRNA that can specifically and effectively silence disease related genes. Such technology has demonstrated the effective use of short interfering as therapeutics. In the absence of a B cell lineage in arthropods, and hence no long term vaccination strategy being available, the introduction of using RNA interference in crustacea may serve as an effective control and preventative measure for viral diseases for application in aquaculture
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