Virologists at the University of Wisconsin – Madison have completed a detailed study of the H1N1 swine flu virus, and the news is…well, it’s less than good.

The virus, which has demonstrated a filament shape unusual in flu viruses, has the potential to be much more severe than most researchers have thought so far. That’s because, in addition to being more apt to reproduce itself within lung tissue, the H1N1 virus has demonstrated an ability to infect cells deep within lung tissue far beyond that of a standard seasonal flu virus.

This capacity for infiltrating further into the lungs distinguishes the H1N1 virus, according to researchers, including study leader Dr. Yoshihiro Kawaoka, who stated that “There is clear evidence the virus is different than seasonal influenza.” Where most flu viruses only affect the upper respiratory system, the H1N1 bug can go much deeper, bringing about pneumonia, bronchitis and possibly death.

The truly unnerving thing to note about this study, published this month in the journal Nature, is that the ability to penetrate deep into the lungs is something we’ve seen before. The trait was also expressed in the 1918 flu pandemic that killed tens of millions worldwide. The fact that people born before 1918 seem to have antibodies against the H1N1 swine flu further suggests that we’re looking at a flu virus whose closest corollary wiped out significant swaths of humanity almost a century ago, when passing flu from one community to another was significantly more difficult.

In other words – this could be a bad one. And while most people seem to have stopped worrying about it, I’m staying at a Level Orange Alert (at least while we still have one) on the matter of a swine flu pandemic. Not every disease du’ jour is going to be the next big thing in global health crises (see also, SARS, bird flu, West Nile virus) but eventually, something is going to break big, and the current H1N1 strain is a pretty likely candidate for doing some real damage. Add to that the fact that a serious outbreak (deaths, high fear of contagion, etc.) during  flu season in the US this year would deliver a hammer blow to a global economy still struggling to get it’s feet, and set back progress on that front at a time we can ill afford it?

Sound like a worst case scenario? It is. But it’s not at all one that’s outside the realm of possibility right now. And I know I may sound unreasonably doom and gloom, but hey, a paranoid is just someone who has all the facts, right? I’m not saying the sky is falling, but the common consensus seems to be that this thing is no cause for concern, an I just don’t buy that line.

The study does have a silver lining, in that anti-viral drugs seemed to be an effective first line of defense against the virus. But with a working vaccine probably unavailable until the end of the year, they’re also the only line of defense at this point.