One notable characteristic of the four previous influenza pandemics is that they occurred in multiple waves. The 1918 pandemic began with outbreaks of low mortality in the spring and summer, followed by a more lethal wave in the winter. This pattern has fueled speculation that the current H1N1 pandemic strain ...

Readers of virology blog have no doubt seen news reports that a Brazilian influenza isolate called A/Sao Paulo/1454/2009 (H1N1) is novel strain with mutations that enable it to infect new hosts. Here is one example of such a report, from The Australian: Brazilian scientists have identified a new strain of ...

A network of ~150 laboratories in the United States participate in virological surveillance for influenza. The results of these analyses are publicly available, and provide extremely interesting characterization of the pandemic spread of the new H1N1 strain. During week 22, 6,664 samples were submitted for testing, of which 2,681 were ...

WHO reports that as of 15 June 2009, 76 countries have officially reported 35, 928 cases of influenza A(H1N1) infection, including 163 deaths. These numbers can be used to calculate a case fatality ratio (CFR) of 0.45%. Is this number an accurate indication of the lethality of influenza? Determining how ...

Viruses are known to evade the early, or innate, host defenses by interfering with the sensing of infection, production of IFN, and synthesis and activity of ISGs. Today we'll examine the evidence that the function of one or more ISGs is blocked in poliovirus-infected cells. When IFN is added to the medium ...