Newsweek Article on Origin of A(H1N1)

The following was taken from the Newsweek article (below).

We have a new virus in the world that appears to be very contagious between people, and possibly between swine and humans. It is, fortunately, treatable with the antiviral drugs Tamiflu and Relenza (oseltamivir and zanamivir), but it is resistant to the other major class of anti-flu drugs, amantadines. It is still evolving, and moving, and its ultimate trajectory cannot be seen right now. We do not yet know how deadly this virus is: while Mexico has been able to track down the numbers of dead and hospitalized H1N1 cases, it cannot determine just how many Mexicans have been infected with the virus since it started spreading there in late March. It's one thing to say that 150 people out of, perhaps, 10 million infected have died: that gives you a case fatality rate that is roughly what we see with normal, seasonal flu. (Each year, seasonal flu kills 36,000 people in the United States alone.) It's quite another story if Mexico's denominator is 5,000, for a case fatality rate of 3 percent--a full percentage point worse than the rate seen with the 1918 influenza. It is urgent that we discern the denominator.

We have a second, closely related H1N1 human virus in circulation around the world. Though widespread, it is not unusually lethal. Last year this virus developed full resistance to Tamiflu. It would be most disturbing if the 2008 H1N1 human virus were to reassort with the new swine/human virus, as we could then be facing a more drug-resistant pandemic strain of influenza, treatable only with the drug Relenza, which must be administered with an inhaler device.

We have a third, older pandemic in poultry, occasionally infecting humans, that involves the H5N1 virus. This pandemic has circulated long enough so that the virus has branched into several evolutionary trees, including forms that are drug-resistant. In Egypt, where it is common for urban families to raise chickens in their yards, H5N1 has caused a significant number of human cases, and its spread appears to be uncontrolled. The World Health Organization (WHO) is distressed by evidence that H5N1 is becoming less deadly for people. That could mean that the bird-flu virus is evolving toward a less-lethal form that is more capable of spreading between people.