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IQ2000 MrNV Detection and Prevention System



Freshwater prawn- Macrobrachium rosenbergii has been viewed as an important species in shrimp farming industry for its high economic value. Though considered to be moderately disease-resistant species when compared to penaeid shrimp, it is also under serious threat to a virus borne disease termed white tail disease (WTD).

The typical gross signs of WTD in infected PL are lethargy and opaque abdominal muscles. Mortality reached 100% within 2 to 3 days after the first appearance of prawns with whitish muscles. The causative agents of this disease are M. rosenbergii nodavirus (MrNV) and extra small virus (XSV). Research result shows that MrNV plays a key role in WTD and that XSV is a satellite virus dependent on MrNV.

Viruses can be detected by almost all organs. They even presented in ovarian tissue which indicates the possibility of vertical transmission of WTD from brooders to larvae and PL. Since M. rosenbergii has a much lower fecundity of 20,000- 30,000, it is more prudent to have berried females tested to prevent the occurrence of WTD at the hatchery stage. Though MrNV and XSV failed to cause mortality in marine shrimp, experiment shows that they were tested positive in most of the organs in P. indicus, P.japonicus and P. monodon.

This system has adopted the design of nested PCR and also inherited the reliability, sensitivity and experience from a range of IQ2000™ virus diagnostic kits for shrimp and fish virus infections. Its unique semi-quantitative function provides information of virus infection levels which could be used for further research on MrNV.


  • Packing size: 200 reactions.
  • Detection Limit: 10 copies/reaction.
  • Quantitative capability: 3 different levels of infection can be differentiated.
  • Sample throughput: for 40 samples, from sample preparation to final results require 3.5 to 4 hours.
  • Built-in internal control system: eliminate false negative results from failed extraction or reaction.
  • Quantified positive standard: monitor the sensitivity of detection.
  • Adaptable to the Uni-IQ RT-PCR profile, suitable for multi-viral diagnosis.

An example of the results is shown and explained below:

Lane 1:  MrNV P(+) standard, 2,000 copies/reaction
Lane 2:  MrNV P(+) standard, 200 copies/reaction
Lane 3:  MrNV P(+) standard, 20 copies/reaction
Lane 4:  Negative control (ddH2O)
Lane 5:  Sample of severe MrNV infection
Lane 6:  Sample of moderate MrNV infection
Lane 7:  MrNV negative sample
Lane M:  Molecular weight markers, 848 bp, 630 bp, 333 bp


  • This reagent is intended for testing fresh, frozen, and ethanol-preserved samples, e.g. gill and PL.
  • Ideal for the specific pathogen-free (SPF) animal selection, evaluation of culture environment, grow-out monitoring, and quarantine service.


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