SLOW, LATENT AND TEMPERATE VIRUS INFECTIONS

In 1957, Gajdusek and Zigas first described kuru, a disease characterized by progressive ataxia, tremor and emotional lability, and confined to the Fore people of New Guinea and their nearest neighbors. In 1959, Hadlow pointed out the similarity in pathology of kuru and of scrapie, a progressive cerebello-hypothalamic neuronal degeneration of sheep, of long incubation. The demonstration of a scrapie "agent," transmissible to goats and mice, stimulated renewed efforts to transmit kuru. These experiments form part of a lorfg-term investigation of chronic human neurological disorders by Gajdusek and his colleagues at the National Institute of Neurological Diseases and Blindness. On their initiative, a Workshop-Symposium was held in December 1964 on chronic human and animal diseases of known or suspected viral etiology. This Monograph, published in 1965, comprises the papers and discussions presented at that Symposium. It constitutes a fitting, though unofficial, memorial to the late Dr. Bj6rn Sigurdsson, whose studies of the virus-induced Icelandic sheep diseases-rida, visna, maedi, and pulmonary adenomatosis-led him to formulate the concept of "slow," as distinct from acute and chronic, virus infections: i.e., gradually worsening processes, preceded by a long subclinical period, and usually ending in death, associated with a persisting, and even tolerated, virus, whose insidious ravages are not halted, and may indeed be aggravated, by the host's immune mechanism. These "gentle yet deadly agents," as Hotchin terms them in his discussion of LCM virus infection, are now called "slow viruses." Besides the diseases mentioned above, the Monograph deals with (a) the slow virus infections of mink, Aleutian disease and transmissible encephalopathy; (b) certain chronic human central nervous system diseases, including multiple sclerosis, amyotrophic lateral sclerosis, Vilyuisk encephalomyelitis, and the sequelae of tick-borne encephalitis-all proposed as slow virus infections by Soviet virologists; (c) immunological aspects of chronic neurological disorders in animals and man; and (d) the role of the host's genetic constitution in the pathogenesis of subacute and chronic virus infections. The two-year gap between the Workshop and the receipt of this Monograph for review is a considerable one, even in this field of long incubation periods! Despite a sprinkling of updating supplements to bring things up to August 1965, various developments have of necessity barely been mentioned, if at all. Perhaps the most notable of these, from the laboratory of the Editors themselves, is the production of a kuru-like syndrome in chimpanzees after intracerebral inoculation of brain from fatal cases: 7 out of 8 have developed the syndrome (see Lancet, 12 November 1966; and New Engl. J. Med., 16 February 1967), from 18 to 30 months after inoculation; 3 chimpanzees inoculated with brain from the first animal to