Friday, February 8, 2008

New arenavirus in transplant patients!!

NEJM just came out with a report in which they found a new arenavirus in three transplant recipients that ended up dying. The clinical course of the disease was encephalopathy followed by death four to six weeks post-exposure. The authors warn that they haven't filled Koch's postulates, but that they are strongly led to believe that the new arenavirus is what caused their fatal disease. 1) all three donors seem to have died the same number of days post-exposure; 2) identical sequences were recovered from all three; 3) it is not found in people outside of this cluster; 4) serologic analysis of the donor revealed evidence of recent infection (he died, too). Beyond finding a new arenavirus, they also used a new method in order to search for the virus--unbiased high-throughput sequencing. This method involves first using RT-PCR, then random PCR amplification, then adapter ligation (it was unclear from this article, but I think that means ligating a protein that will attach to the bead in the next step for oil-water emulsion PCR), then oil-water emulsion PCR (use multiple identical sequences attached to a bead in order to selectively sequence them by pyrosequencing), sequencing by pyrosequencing, the adaptors are trimmed, redundant sequences of the reads are ignored, and the entire sequence identified by BLASTN and BLASTX. Okay, so maybe I don't fully understand that process, but it seems cool!

"A new arenavirus in a cluster of fatal transplant-associated diseases" 2008 in NEJM by G Palacios et al, p 1-8


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