The Genome Sequencer system represents a new standard of virus recognition having identified the virus where other methods failed. Knowledge of the genetic sequence of this virus might enable improvements in screening that will enhance the safety of transplantation.
Transplantation is different from other surgical disciplines not only because the surgery involves organ replacement but also because of the complexity of the postoperative care required.
A technically successful operation can still fail if the patient succumbs to infection or a side-effect of the treatment given. Thus, the practice of transplantation requires the medical skills needed to judge the correct doses of immunosuppressive drugs and to control the diverse medical complications which occur in these patients.
Researchers at Columbia University and Victorian Infectious Disease Reference Laboratory discovered the unknown virus as a relation to the lymphocytic choreomeningitis and Kodoko virus.
Results published in the online in New England Journal of Medicine were gathered using the 454 Sequencing technology, an ultra-high-throughput DNA sequencing tool that produces tens of millions of bases per hour on a single instrument allowing complex regions of genomes can be analysed without the time or cost constraints of current DNA sequencing methods.
The researchers took tissue from the transplanted organs, which all originated from the same donor. From this researchers were able to generate a library of more than 100,000 RNA sequence fragments.
From this starting point the scientists were able to eliminate fragments of known sequences leaving the genetic sequence of the unknown arenavirus.
Culture, electron microscopy, and immunohistochemical and serologic tests were used to confirm victims had been infected by this new virus.
"Within a few days we had clues to the identity of the virus responsible for transplant deaths," said Ian Lipkin, lead author of the study at Columbia University.
"Our success reflected the tireless efforts of an extraordinary team of investigators representing academia, public health and industry, who brought all of their expertise and technology to bear on an important clinical problem," he added.
Results of the study implicate this new arenavirus as a human pathogen and support the use of high throughput sequencing in pathogen discovery.
High-throughput sequencing has often been used to characterise complex mixtures of microorganisms in a particular area and can be used to address a suspected outbreak of infectious disease. This technique may prove useful as a new tool in the identification and surveillance of pathogens in chronic as well as acute disease.
"This metagenomics approach to pathogen identification may facilitate a more rapid response when the 'next SARS' emerges sometime in the future," the study added.
The lymphocytic choreomeningitis virus normally has little effect on healthy people but can be deadly for people whose immune system has been weakened. Person-to-person transmission does not usually occur, with the exception of vertical transmission from an infected mother to foetus.
The study entitled, 'Discovery and implication of a novel arenavirus in a cluster of fatal transplant associated disease', can be found here .
