More on how viruses interact with bacteria

Many deaths from influenza are actually caused by secondary bacterial infections. However, the link between influenza viruses and bacteria are not well understood. Researchers at St. Jude's are studying this question, which has public health preparedness implications for stockpiling antibiotics to prevent excess mortality.

"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 PB1-F2. The gene encoding PB1-F2 is present in nearly all IAVs, including highly pathogenic avian IAVs that have infected humans and the IAV associated with the 1918 pandemic. "PB1-F2 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 finding that PB1-F2 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 PB1-F2 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."