Monday, March 7, 2011


Two relevant but rather different papers in the latest Proceedings of the National Academy of Sciences (PNAS).

In the first: Bacillus anthracis comparative genome analysis in support of the Amerithrax investigation, they describe how genomic analysis was used in the investigation of the 2001 anthrax attacks.

The paper describes how the Institute for Genome Sciences faculty and collaborators from the FBI found that the anthrax samples used in all the attacks were genetically identical. Later, another group of scientists -- also including Institute for Genome Sciences faculty -- would trace the anthrax spore used in the letters back to a flask of Bacillus anthracis and several samples taken from that flask. The primary custodian of the flask was Bruce Ivins, Ph.D., a scientist at a U.S. Army biodefense laboratory in Maryland. With this key investigative lead from the scientific team, the FBI used additional police work to conclude that Dr. Ivins was the perpetrator of the mail attacks. Dr. Ivins killed himself before the case could go to court. The FBI has since closed the Amerithrax investigation. (From a report at ScienceDaily)

In the second paper, Hybrid influenza viruses may have pandemic potential, which is relevant to this weeks discussion,  the authors describe how the H1N1 strain that caused the 2009 pandemic, but relatively few deaths, may yet turn out to be problematic. 

The H1N1 influenza virus that spawned the 2009 pandemic is now predicted to circulate as a seasonal flu. However, researchers fear it could once again present a major public health threat by recombining with the H9N2 virus, which is endemic to several bird species in Asia, and has infected pigs and humans. Yipeng Sun et al. explored this possibility by dissecting the H1N1/2009 and H9N2 influenza viruses, and systematically mixing their genes to generate 127 hybrid viruses. The authors then tested the hybrid viruses in mice to assess the likelihood that genetic reassortment between H1N1/2009 and H9N2 could create a virus of pandemic proportions. More than half of the hybrid viruses instantly infected mice and replicated as efficiently as did the parent strains. Eight of the hybrids proved more virulent and dangerous than did either of the two parent strains. Curiously, each of these eight strains carried a gene encoding part of the RNA polymerase, known as the PA gene, from the pandemic H1N1/2009 virus. The authors suggest that the pandemic PA gene may play a key role in the virus’s pathogenicity, and that screening H9 viruses for the gene might help identify influenza viruses that pose a public health risk.

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