Book Review

Emerging Viruses

N Engl J Med 1993; 329:1431-1432November 4, 1993

Article

Emerging Viruses
Edited by Stephen S. Morse. 317 pp., illustrated. New York, Oxford University Press, 1993. $39.95. ISBN: 0-19-507444-0

This important book examines the biologic, ecologic, and social factors responsible for the continuing emergence of new viral diseases. It is an update of a 1989 conference sponsored by the National Institutes of Health and Rockefeller University. Coverage is not encyclopedic, but selective, with illustrative examples presented in 28 chapters by 44 authors who represent a spectrum of academic, national, and international institutions. Only a few of the interesting concepts and facts in this book can be cited here.

In view of the current outbreak of hantavirus disease in the southwestern United States, the chapter on Hantaan (Korean hemorrhagic fever) and rodent zoonoses by LeDuc and associates is of particular interest. In the Baltimore area, rats harbor a hantavirus; three patients at Johns Hopkins Hospital have been shown to be infected with this agent, recognition of which awaited the development of techniques for viral identification.

Morse in chapter 2, Shope and Evans in chapter 11, and Monath in chapter 13 emphasize the human factor in the environmental changes that, by promoting contact with agents or their vectors, lead to the epidemic spread of viruses. Infrequently, a novel virus will appear under circumstances that suggest an evolutionary change in the agent. Monath lists Kysanur Forest disease, Rocio encephalitis, and O'nyong-nyong as possible examples.

Webster presents evidence that group A influenza strains are especially subject to mutational and recombinant alterations. Studies indicate that all the genes of the world's influenza viruses are maintained in aquatic birds, in which they cause no disease. Both the 1957 Asian and the 1968 Hong Kong epidemic strains contained genes derived directly from the avian reservoir. Pigs and humans can acquire avian strains and can transmit the viruses to each other. Strains can become virulent for new hosts, as shown by virologic studies of seals that died in the Boston area in 1980 and of a lethal outbreak on chicken farms in Pennsylvania in 1983. The situation in reservoir hosts is such that we may at any time face epidemic influenza similar to that of 1918 and 1919, when the number of deaths from the disease exceeded the number due to any war of the past 150 years.

Myers, MacInnes, and Myers examine the relations among the five simian and human immunodeficiency viruses. A simian origin of the human types is likely, but the reason for the cross-species transmission is not known. One possibility I have considered is the eating of monkeys. I remember my shock in 1952 when in a market in Monrovia, Liberia, I saw mounds of cooked humanoid legs, arms, and other body parts; monkeys were a staple dietary item. The civil strife of more recent African history has produced food shortages and probably greatly increased the collection of monkeys for consumption.

The gross inadequacies of contemporary medical and health organizations are dramatically emphasized in a chapter describing a hypothetical 1994 epidemic of a lethal Ebola-like virus that spreads from an African focus to every continent. Reference is made to the 1987 report of the National Research Council and the Institute of Medicine that documented the inadequate capacity of the United States to respond to the problems posed by tropical diseases. The situation has deteriorated further as budgetary constraints have affected academia, public health services, and the military. In a subsequent chapter, Henderson stresses the woefully inadequate nature of current surveillance systems for the detection of epidemics of viral disease. He makes a strong plea for the development of a network of 15 internationally supported surveillance centers in the tropics, with the participation of scientists from 10 strengthened centers for tropical medicine in the United States. The capacity of the Centers for Disease Control and Prevention should be expanded to cope with epidemic episodes. Henderson estimates that this modest goal could be achieved with an annual expenditure of $150 million. He concludes that the question is, Can we afford not to invest in a program that could be a determinant in our own survival as a species?

This book should appeal to a wide readership. It should be read by those responsible for curriculum design for medical and public health schools, by all professional workers dealing with infectious diseases, by biomedical writers responsible for informing the public, and by those responsible for determining priorities for the funding of health programs and biomedical research and training.

Thomas H. Weller, M.D.
56 Winding River Rd., Needham, MA 02192