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March 9, 1997
Killers Among Us By JOHN R. G. TURNER
Lethal viruses are no accident but an evolutionary certainty
VIRUS X
Tracking the New Killer Plagues --
Out of the Present and Into the Future.
By Frank Ryan.
Illustrated. 430 pp. Boston:
Little, Brown & Company. $24.95.
n the way to his fiancee's funeral, a young Navajo is taken seriously ill. By the time his father has called the ambulance, the young man is prostrate in the dirt of the parking lot. Three hours later he is dead, with a constellation of symptoms -- a flu-like sickness turning to unbearable muscle pains and shortness of breath, progressing with exceptional speed to death from water-filled lungs -- that the doctors have never seen before. Except in his fiancee. Were they poisoned? Was it a new form of drug abuse? Or an unusual reaction to pneumonic plague, endemic in that part of New Mexico?
So begins the detective story that occupies the opening chapters of ''Virus X.'' Like all good detective stories, it has a quietly dropped clue (the weather was odd that summer), and like the reviewers of all detective stories, I will observe the decencies and not reveal the solution, except that Frank Ryan surely intended the book's title as another clue.
If these chapters are mystery stories, the ensuing chapters on Ebola virus are horror tales: a young Zairian student nurse dies terrified and sedated with Valium, attended only by a medical team disguised as astronauts. The international trouble-shooters are on the verge of putting the whole city of Kinshasa in quarantine. This story has no solution: the dreadful virus with the world record for killing those infected comes out of the rain forest from an unknown animal source and spreads among people, largely through intimate contact and the re-use of hypodermic needles; the epidemic is over only after the authorities call for outside assistance and institute containment procedures.
Cut now to the next blockbuster disaster movie: in the tropics a villager is hunting monkeys, some for the pot, some for the export market in laboratory animals. One that is not quite dead, but bleeding profusely, bites and scratches him. A virus from the monkey incubates in the hunter's body. He passes it to his family and other villagers. Most show no symptoms worth noticing, but some feel strange enough to check in at the rural hospital. The hospital spreads the virus by recycling its inadequate supply of hypodermic syringes and surgical gowns. Several hundred people are infected, some in the neighboring town. Only after it has traveled to the capital, to the airport and then to other continents does the virus strike, by producing horrendous and lethal symptoms. Amid panic, blame-casting, lack of adequate surveillance even in the developed world and international politicking, millions are infected, millions die. There is no effective treatment or vaccine.
The end of this disaster movie? Is the human race extinct? Does a nucleus of resistant individuals found a new population that painfully reassembles the destroyed human culture? Or does the cavalry in protective suits find a vaccine and a miracle cure? We do not know the ending, yet; this is in essence the story of AIDS.
Worse is to come: What if -- as Joshua Lederberg, the Nobel Prize-winning geneticist asked -- there were a virus as lethal as Ebola and with a long incubation like H.I.V. that instead of ''rounding the world from bed to bed as pretty as you please'' (as Richard Wilbur's translation of ''Candide'' has it) were to spread by droplet infection from the nose and mouth, like a head cold?
Could there be such a virus? Quite possibly, according to Dr. Ryan, and our chances of catching it are increasing. He points out that, as is well known, every species has viruses with which it is in more or less friendly equilibrium. Herpes simplex in humans is relatively benign, usually producing no more than mild facial ''cold'' sores in a minority of those infected, and most people are infected. Such viruses, however, produce fulminating symptoms if they succeed in infecting a related species: conservationists should contemplate with horror the possibility that an animal lover could perhaps wipe out the gorilla or the chimpanzee simply by giving one a herpes simplex kiss. Likewise, viruses that produce no effect in monkeys or rodents, or indeed many other animals, have lethal potential for us.
Here Dr. Ryan makes an original and challenging suggestion (skeptical biologists should take it seriously): this situation is no accident. These viruses are ''aggressive symbionts,'' like the ants that live in special chambers created for them by some tropical acacia bushes: browse the bush and out comes a defending army. Likewise, invade the territory of another species and it will give you its aggressive virus to wipe you out. H.I.V.-2 came to us this way from a West African monkey, and H.I.V.-1 probably from the chimpanzee. Once, a nucleic acid war between us and other mammals would simply wipe out a hunter-gatherer village. Now the whole world hunts and gathers in the tropical rain forests -- those huge stores of species (many times greater than in the whole of the rest of the planet) once effectively defended by their aggressive symbionts but now vulnerable to our expanding populations and technologies. Thus we are in contact with every one of the world's other species, uncounted millions of them, and our speed of travel round our own village takes their viruses across continents before you can say ''night sweats.''
Dr. Ryan, a physician and the author of a previous popular book on tuberculosis, writes well in a difficult technical field, weaving the technicalities of scientific history, medicine, molecular biology and evolution into the human narratives of a sequence of epidemics, with victims, heroes (the medical teams) and villains (politicians, more or less). There are so many characters that his thumbnail sketches of the scientists do not always bring them to life, but it is nice to see the great Joshua Lederberg starting as a ''heavyset young graduate student'' presenting a paper at the end of a grueling conference and reappearing chapters later as a living legend with a Rabelaisian wit.
The message of this very readable and disturbing book is, as Hamlet says, ''if it be not now, yet it will come: the readiness is all.'' We need to consider our readiness.
John R. G. Turner is the Professor of Evolutionary Genetics at the University of Leeds, England. His publications encompass a hundred scientific papers as well as translations of Rimbaud.
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