Molecular Sharks : The dizzying matter of where a virus fits into the grand scheme and where humans fit into nature’s humbling plan : THE HOT ZONE, <i> By Richard Preston (Random House: $23; 352 pp.)</i>

“The Hot Zone” got out of my backpack while I was off fishing. There were other choices in our motley array of tents--Cormac McCarthy novels, Paul Bowles stories, “The Magic Mountain” and Ralph Cutter’s “Sierra Trout Guide.” But it was my nondescript advance proof of “The Hot Zone” that inflamed Jim’s interest, and for the rest of our five-day trip the book and its story spread.

Under a full moon, with kids whittling around a comforting fire, Jim recalled a scene in which researchers slice through single cells with a diamond blade so sharp you would never feel its prick. The book jumped to Paul. Paul read feverishly, then described the hideous event known as “bleeding out.” “The Hot Zone” passed to a Bay Area friend.

I didn’t regain possession and start reading until we returned to civilization. Only then, after involuntarily blurting “Oh no!” mid-sentence, did I fully comprehend the book’s infectiousness.

What we had on that remote lake shore in the Sierra Nevada, I now realize, was a “microbreak.” The story had erupted and, for the moment, been geographically contained. Trust me on this, though--”The Hot Zone” is going to sweep the population like fresh gossip in an office with E-mail.

And the whole story is true.

The passage that caused my uncharacteristic outburst comes a few chapters into Richard Preston’s tour de force. Major Nancy Jaax, a veterinarian in the U.S. Army’s little-known Medical Research Institute of Infectious Diseases, has just taped herself into a sealed Chemturion biological “space suit” and stepped through an airlock into a dangerous and obsessively controlled Level 4 biocontainment area known as “the hot zone.”

Soon Jaax is ripping apart a diseased monkey’s skull. Wrist-deep in blood and tissue, she thinks: “No blood. I don’t like blood. Every time I see a drop of blood, I see a billion viruses.”

Jaax, is investigating a “filovirus” called Ebola, a “Level 4 hot agent” which, by definition, is lethal and contagious, and has no vaccine or cure. It is, we are told, “a perfect parasite because it transforms virtually every part of the body into a digested slime of virus particles.”

In 1967, a filovirus traveled to Germany in the blood of an African Green monkey. There it “jumped species” to a man who handled research primates, and started spreading so quickly, Preston says, that for a few days “doctors in the city thought the world was coming to an end.”

In 1976, a hot agent known as Ebola Zaire emerged like a phantom tiger from the jungle. It rampaged through 55 villages, slaughtering nine out of ten people it infected, before mysteriously petering out. Most such “microbreaks” have remained confined to Africa. But there is no doubting the virus’ ambition.

In one scene, Preston describes a virus undergoing “extreme amplification” at a Nairobi hospital. As the afflicted patient dies, blood and bile spout from every orifice, letting the virus find new “hosts” in doctors and nurses.

Earlier, the passengers of a crowded plane watched the same patient fill his airsickness bag to the brim with black vomit, a substance that smells like a slaughterhouse and swarms with the wildly contagious disease. In case anyone misses the point, Preston reminds us: “A hot virus from the rain forest lives within a twenty-four hour plane flight from every city on earth.”

Now that HIV--a mere Level 2 agent--has cut its tragic swath, it’s hard to dismiss such observations as alarmist melodrama. And remember: “Ebola does in ten days what it takes AIDS ten years to accomplish.”

Given such startling facts, “Hot Zone” left me craving more biology. But it’s clear why Preston pruned as he did. He uses the power of simple narrative to drive deep this story’s urgent truths. Well-placed lyrical asides lodge Preston’s biological mystery in parts of the mind that straight science often leaves untouched: troops of monkeys leap through the crowns of camphor trees at night; villagers sob outside huts in which their loved ones writhe and die; mummified baby elephants litter a crevasse in a cave where the virus may hibernate in insect or mammal hosts.

In the book’s credits, Preston recalls feeding his editor the cliche: “God is in the details.”

“No,” she replied. “God is in the structure.”

Preston, as it happens, is a master of both. In a scene that illuminates Nancy Jaax’s harried domestic life, the wife and mother slices the palm of her hand while hastily opening a can of beans with a butcher knife. Preston reveals this detail--along with the disturbing particulars of Ebola’s aggression--just before Jaax performs the monkey autopsy. How could I not blurt “Oh no!” when Jaax spotted the hole in her blood-sopped “space suit”?

Throughout the book, horror lurks on the edge of banality. “The Hot Zone’s” central crisis is a 1989 filovirus outbreak that decimated a population of several hundred research monkeys, at a corporate laboratory in suburban Virginia. Not knowing whether this strain of virus is deadly to human primates, suspecting that it may transmit through the air, Jaax joins a biocontainment assault. She enters the disease-ridden building to the squeals of children playing at a nearby preschool.

It is bad form to reveal a book’s ending. I can say, though, that if you’re alive to read this, events did not hand Preston his most dramatic climax.

Don’t be disappointed. Gripping as Preston’s real-life plot may be, the questions “The Hot Zone” provokes are even more compelling. For instance: As new viral agents emerge, biological emergencies and individual liberties are bound to collide. (Remember the furor that has surrounded “fascist/lunatic” suggestions to isolate people with AIDS? How about murder charges against knowingly HIV-infected who have unprotected sex?) Where will the lines be drawn and by whom?

“The Hot Zone” also inspires navel-gazing of a more fundamental sort. In his acclaimed book, “First Light,” Preston put his talents to the study of the stars. “The Hot Zone” is strewn with astronomic metaphors. They’re not gratuitous: microscopes as well as telescopes probe the cosmos. As Preston says in describing a hot zone researcher’s scrutiny of a magnified cell:

“What loomed before his eyes was a huge, complicated vista, crowded with more detail than the mind could absorb. He might have been a navigator of a starship making a low-orbit pass over a huge, unexplored planet. . . . The cell was a world down there, and somewhere in that jungle hid a virus.”

Viruses, Preston says, are “molecular sharks, a motive without a mind. . . . They exist in the borderlands between life and nonlife.”

Yet it is barely possible to consider these things without discussing their “strategy” for attaining their apparent raison d’etre--which is to spread like an imperialist army. “The more one contemplates the hot viruses,” Preston says, “the less they look like parasites, and the more they begin to look like predators.”

Karl Johnson, the “discoverer” of the Ebola virus, remains in abject fear of the potential devastation it or some other hot agent could inflict on our species. Yet, Johnson tells the author, “I’m so glad nature is not benign. . . .”

“Do you find the virus beautiful?” the author asks, as Johnson casts an imitation fly on the trout-rich waters of Montana’s Bighorn river.

“Oh yeah,” Johnson says softly, one predator in awe of another.

The dizzying matter of just where a virus fits into God’s grand scheme, or where we humans fit into nature’s more humbling plan, runs through the “The Hot Zone” like the echo of a Zen koan. So it is really annoying when, in the book’s final section, Preston steps out of his poet-journalist role and leaps with preacherly zeal onto a stump.

The earth, he declares, is “beginning to react to the human parasite, the flooding infection of people, the dead spots of concrete all over the planet, the cancerous rot outs in Europe. . . .”

That we humans have been slothful environmental stewards seems beyond debate. Perhaps, as the Gaia theorists would have it, the earth is a throbbing organism that’s not gonna take our guff anymore. On the other hand, it’s equally plausible that our species has burgeoned exactly in order to survive the predations of AIDS, Ebola et. al.--Hey! All the other parasites do it!

In any case, such trite speculation is only a momentary distraction from the subtler ruminations Preston’s fine story-telling stirs.

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