Public release date: 10-Oct-2007
It is relatively rare for an influenza virus to be virulent enough to cause death in healthy humans. Many deaths associated with influenza are caused by the combined influence of viral disease and the following secondary bacterial infection. Although the 1918 pandemic strain was one of the few influenza viruses capable of killing healthy victims on its own, the majority of fatal cases from the “Spanish Flu” can be attributed to secondary bacterial pathogens rather than primary viral disease. This important interaction between influenza viruses and bacteria is not well understood.
Dr. Jonathan A. McCullers from the Department of Infectious Diseases at St. Jude Children’s Research Hospital in Memphis, Tennessee and colleagues examined this interaction by studying a newly discovered influenza A virus (IAV) protein, called ?????. The gene encoding ?????is present in nearly all IAVs, including highly pathogenic avian IAVs that have infected humans and the IAV associated with the 1918 pandemic. “????? was recently shown to enhance viral pathogenicity in a mouse infection model, raising questions about its effects on the secondary bacterial infections associated with high levels of influenza morbidity and mortality,” explains Dr. McCullers.
The researchers found that expression of ?????increased the incidence of and exacerbated secondary bacterial pneumonia in a mouse model. Intranasal delivery of a synthetic peptide derived from a portion of ?????had the same effects. Further, an influenza virus engineered to express a version of ?????identical to that in the 1918 pandemic strain was more virulent in mice and led to more severe bacterial pneumonia, explaining in part both the unparalleled virulence of the 1918 strain and the high incidence of fatal pneumonia during the pandemic.
The finding that ?????promotes lung pathology in primary viral infection and secondary bacterial infection also provides critical information for the future. “Given the importance of IAV as a leading cause of virus-induced morbidity and mortality year in and year out, and its potential to kill tens of millions in the inevitable pandemic that may have its genesis in the viruses currently circulating in southeast Asia, it is imperative to understand the role of ?????in IAV pathogenicity in humans and animals,” says Dr. McCullers. “These findings also reinforce the recent suggestion of the American Society for Microbiology that nations should stockpile antibiotics for the next pandemic, since many of the deaths during this event are likely to be caused by bacterial super-infections.”
Ralph’s Note – I replaced the protein type with question marks, in protest of the release of this information. How easy due we want the next pandemic to be created through an act of terrorism? This should be a DOD project only…