ZOONOSIS

Uh-oh.

During the past few years, I have discussed avian flu (bird flu) occasionally, and somewhat cautiously, in class. I'm not a "catastrophist", someone who sees disaster lurking around every corner. I believe that climate change is real, but I also have faith in mankind's ingenuity to adapt and change. I didn't get concerned about the alleged Y2K virus that was to have shut down all personal computers, as well as global air traffic control networks, train systems, banking systems, and other computer based management systems. And as I told my wife Sue several years ago, I wasn't too concerned about avian flu, "Unless", I told her "the virus jumps into pigs - that would concern me".

Consider me concerned.

There are about 15 known strains of virus. Some effect birds/water fowl. Some effect humans. The organisms are genetically different enough in these two classes that viral strain rarely jump from one class (Aves) to another (Mammalia). There are a few viral strains however, that effect birds, swine, and humans. Swine are mammals. We are mammals. Swine there can act as a viral bridge, allowing an avian flu to "migrate" into, and infect, humans.

This transmission of disease from animals to humans is called zoonosis. (I can hear Jenny now, bristling at the notion that humans are not animals, and we consider ourselves, somehow "different". A perfect segue into our next book, Ishmael.) We may in fact be animals, but viruses seem to specialize and distinguish between different classes of animals. This distinction has shielded humans from many diseases.

The swine flu being reported in Mexico is a combination of avian and swine flu. At this time, it is being reported in Mexico, New York, California, Texas, Kansas, Israel, New Zealand, France and Hong Kong. Human immune systems are encountering this bug and saying "Huh? What's this?" Not knowing how to respond, those who are infected find themselves with immune systems going into overdrive - sometimes to their own detriment.

If I were to make a hypothesis it would be this: we are about to see a global pandemic. The first wave will be relative mild with relatively few infections. Then, Darwinian principles will kick in, the "strongest viruses will survive" and adapt to Tamiflu or whatever is being used against them, and a second, more serious wave of viral infections will occur. It's important to keep all of this in perspective. Influenza is always to be treated as a potentially serious disease. The "flu" is responsible 35,000 deaths in the US each year, mostly in our most vulnerable population groups - infants and the elderly. And there was another swine flu alert put out in 1976, but that epidemic never materialized - certainly not to anything approaching global pandemic levels.

Hopefully, I will be proved wrong (It will not be the first time!) and this whole thing will fizzle out. But this is my current thinking on the matter. Transmission is exponential; 2 pass it on to 4, and on to 8, 16, 32, 64, 128, 256, 512, 1024 etc. We should have a much clearer sense of where this thing is heading towards the end of this week.

While several people in Mexico have died, they reportedly did not seek treatment. At this point, no Americans have died from the swine flu. A primary concern is that this strain of flu seems to be targeting young, otherwise healthy teenagers and adults, rather then the typically vulnerable populations.

My advice to you all is the same advice I've given my own kids: wash your hands, follow new developments in the news, and if you begin to feel any flu-like symptoms (tiredness, joint-aches, fever, disorientation) get thee to a physician!

As disturbing as these recent developments are, I could not have planned a better illustration of what we have been studying these past few weeks. Infectious agents kick one's immune system into gear. The virus presents an antigen/epitope not previous known to one's immune system. One gets tested for swine flu with an Enzyme Linked Immuno-Sorbant Assay, and then receives treatment based on a positive or negative indicator in the test.

Sometimes the real-life connections are a little too real.

So where did this swine flu virus come from? Aren't there always viruses? How did it make the "leap" from birds to pigs to humans? How? It evolved. And that, dear students, will lead us to another relevant "real-life" connection this week as we acquaint ourselves with Darwin's elegantly simple, yet utterly profound, thoughts on the diversity of life on earth: the theory of evolution.

BIRD POPULATIONS IN DECLINE

"Evening summer breeze / sweet warblings of the meadowlark / moonlight in Vermont....."

Moonlight In Vermont. Great, great song. I was walking down the hallway past Mr. Mellinger's room last week, and heard the band practicing the tune. Stuck my head in to congratulate the musicians and singer - the song has a killer key change in the middle "bridge", and they really nailed it. Couldn't get it out of my head as I returned to the biology room....and kept thinking about that meadowlark. I couldn't recall seeing a meadowlark for a long time.

Turns out there's a probable reason for the absence. A recent study completed by the Interior Department titled "The State Of The Birds" (catchy title, eh? Just had to be a federal report...) reports that just about all non-waterfowl bird populations have dropped dramatically during the past forty years. Climate change wasn't directly implicated as the primary cuase although it most assuredly is involved. Rather, it is the spread of human populations and development of previously forested woodlands and grasslands that is to blame. As we build more houses, yards, stores, and roads we are changing, and in some cases destroying, the habitats of our bird populations. Birds that thrive in wooded areas or grasslands hesitate, or refuse, to cross over new open parcels of land, which indicate a territorial boundary to them. Invasive species move in. Disease spreads. Populations teeter on extinction.

Fortunately, bird advocates and worked with sport hunters to lobby for hundreds of millions of dollars of federal aid to protect endangered species. Yet placing birds on an endangered species list, may impact other environmentally important projects. For example, the lesser prairie chicken lives in the the southwest. Like many grassland species, its population has dropped about 40% during the last four decades. While it may deserve designation as an endangered species, doing so would place severe limitations on the entrepreneurs efforts to develop wind power turbines in that region. How does one place a value on a bird species versus the need for more, and cleaner, energy?

When I moved to the Upper Valley in the mid 1980s I was awakened each morning by a cacophony of bird song. Currently, more often than not, it is very quiet when I awaken - even on weekends. I hear the occasional song of some resident birds, but it is nothing like it was 25 years ago.

And I wonder, is this another "silent spring"? One not caused by use of pesticides, but rather, a more benign neglect in the name of progress?