Initial Identification and Characterization of an Emerging Zoonotic Influenza Prior to Pandemic Spread.

摘要

Two cases of influenza-like illness associated with untypeable influenza A were identified in Southern California during March 2009. One was initially identified as influenza using an experimental diagnostic device in a clinical trial, while the other was identified at a local reference lab using a diagnostic PCR assay. In both cases, analyses yielded negative results for strain-specific tests targeting currently circulating strains of human influenza A, namely seasonal H1 and H3. These two samples became the first reported cases of the 2009 pandemic H1N1 (2009/H1N1) influenza strain. The first reportable characterization was made from the second collected specimen on April 15 at the CDC's central lab using traditional culture and sequencing methods. The novel nature of the strain and its apparent zoonotic origins were initially characterized using the first collected specimen at the Naval Health Research Center in San Diego, California, on April 13, using an experimental molecular analysis tool, PCR/ESI-MS, designed to amplify PCR products from any strain of influenza and to generate informative (phylogenetic) strain identifications through mass spectrometry of PCR amplicons.