AVIAN INFLUENZA

The world has faced three pandemics in the past 80 years, and currently has at least one more on the horizon. The world is abuzz with talk about the sinister H5N1 influenza virus, one species of the otherwise coined avian influenza. But what can effectively be done to minimize its impact once it decides to attack?

Some lessons may be applied from what we learned as the world faced the severe acute respiratory syndrome (SARS) epidemic in 2003. It was a very scary and confusing time. A new virus a new deadly virus one we knew nothing about, was spreading, taking lives as it traveled, and all we had to arm ourselves with to minimize its impact were infection control practices.

Perhaps of most importance in lessons learned from the SARS outbreak is how important it is to keep history from repeating itself, points out Linda R. Greene, RN, MPS, CIC, infection control manager at Via Health Rochester General Hospital in Rochester, N.Y.

In Toronto, the index case presented in a small community hospital. This could easily have occurred in any one of our (American) hospitals. We cannot think that this wont happen to us. The SARS outbreak has taught us that we must be prepared and ever vigilant. In our efforts to increase technology, we must not forget the basics. Appropriate infection prevention and control measures are of the highest priority. Early identification and appropriate isolation when indicated are necessary to contain such respiratory viruses. The outbreak was a sobering and humbling experience which emphasized the fact that infectious diseases now as much as ever can kill, as well as create social and economic havoc. As healthcare workers, we are not exempt from the devastating effects of such an epidemic.

SARS affected a total of 8,098 people worldwide; of which 774 died. Although those numbers come nowhere near the devastation that hit the world in 1918 when an estimated 675,000 Americans died to know and understand the logistics behind the SARS outbreak, is to understand the true advantage infection control measures offered.

Gregory Poland, MD, professor of medicine and infectious diseases at the Mayo Clinic College of Medicine in Rochester, Minn., and director of the Mayo Vaccine Research Group, says Once it became apparent that SARS was something of concern; that is was transmissible; that it was something novel; the word went out.

Appropriate measures took place. And while it still involved something like 8,000 or so people exposed, it did not spread past that. The epidemic was in fact successfully halted in the absence at the time of knowing what the agent was, having no anti-virals, having no medications that were effective, having no vaccine thats pretty remarkable.

Poland adds that the two viruses SARS and avian influenza are very different; both with its own unique processes, so comparing the two really is a bit of a stretch. Nonetheless, I think there are some important lessons, he asserts. When there is good communication between nations public health authorities, the public health officials are capable in conjunction with medical institutions and medical personnel of instituting effective measures.

In this case, the effective measure was quarantine and appropriate infection control precautions. So that principle holds. Now with influenza, what we would implement might be different antivirals, vaccines, infection control precautions it would be a different set of weapons we bring to bear, but the principle is there.

These weapons being developed now apparently face the continuous morphology of this virus. Poland says there have been two published clinical trails of inactivated vaccines that showed both were safe and showed immunogicity that is they show an antibody response that may be protective, But, he adds, of course nobody knows for sure right now.

The problem with these vaccines is it took two doses and it took higher than normal doses. As Poland points out, this is part of the answer toward getting to a vaccine that could be used globally, but not THE answer.

To explain further about the race against the viruses super morphology powers, both of those aforementioned vaccines were built against the so-called clayed 1 viruses. Poland says there have been no H5N1 clayed 1 human viral infections in the last six months; they have basically merged or mutated into clayed 2 viruses which primarily are coming out of Indonesia, he says, and We dont have a clayed 2 vaccine at this point.

There have also been reported isolated instances of H5N1 resistance to TamiFlu. They have been small in number, isolated, dont appear to be increasing in frequency, but definitely something to keep ones eye on, Poland warns.

Poland says it is his hope that the recent government releases of large funding amounts for such developments will spur further interest and thus result in the needed vaccines. This is a very encouraging early preparation in terms of putting the resources into place, he adds. But were still left with the question as to if it will be enough. Were still in the discovery phase, Poland says. There have been several instances of human to human transmission.  Are we and WHO (World Health Organization) says we are still in phase 3, or are we actually in phase 4? I would maintain that we are in phase 4. WHO does not want to move yet off of phase 3 primarily saying they realize this has happened but its been localized; hasnt gone to third and fourth generation cases.

But thats not what their original definition was. Their original definition was evidence of human-to-human transmission. Fortunately, that is the only Achilles heel of this avian influenza virus. It has not yet acquired the ability to infect human cells; at least not efficiently, he continues. For that reason there has not been a more widespread human to human transmission. But anything can happen and there is no timeline for possible occurrences. Nothing would surprise me about an influenza virus. This is an unpredictable virus. Any prediction about this virus is almost certainly wrong, Poland concludes.

For more information on the current events and breakthroughs in the worldwide fight against avian influenza, the Journal of Infectious Diseases (JID) published an influenza- dedicated supplement in its November 15 issue. The supplement features research and opinions of leading experts in the field and is based on presentations from the conference, Seasonal and Pandemic Influenza 2006: At the Crossroads, A Global Opportunity, that was held in Washington, last February. The supplement can be accessed at: http://www.journals.uchicago.edu/JID/journal/contents/v194nS2.html?erFrom=3996305796714019694Guest.