TEXTE PARTIEL :
It has been said that it is one of the prerogatives of age to lecture youth. But another and perhaps more reprehensible prerogative, too often assumed, is for age to lean upon and take advantage of the productiveness and fertility of youthful minds. Indeed, the honor of deliverIng this lecture was accepted with the thought of confessing such trespassing, and recognizing the contributions of younger associates particularly Drs. William F. Scherer and Telford H. Work, who have actively participated in developing the program to be discussed, and to the many contributors from the field and laboratory research units who are working on arthropod-borne viruses and whom we serve in our effort.
This Society has been concerned with the importance of arthropod-borne viruses as they represent a significant portion of the problems to be solved in tropical medicine research today. We have now entered into a new phase of activity which offers promise of accelerating the growth of research a.ndknowledge of this group of disease agents.
Let it be understood that the term arthropod-borne virus as used here refers to anImal viruses which are biologically transmitted by arthropods, or to use the definition given by the WHO Study Group on Arthropod-borne Viruses, "An arthropod-borne animal virus is defined as one which, in nature, can infected haematophagous as one which, in nature, can infect haemophagous arthropods by their ingestion of infected vertebrate blood. It multiplies in their tissues and is transmitted by bite to susceptible vertebrates." This would exclude viruses that may be transmitted by purely mechanical means."
Before considering the objectives of these endeavors, the question may be raised of how important are these viruses as a threat to human health and economy. This question has been admirably answered with appropriate references in two recent review articles by Work on the expanding role of these viruses in tropical medicine and by Hammon on their global importance. It will suffice here to point to the balefull history of yellow fever, its advancement in recent years through the forests of Central America until it is again knocking at our southern door, and its recent northern invasion into Ethiopla with disastrous effects; to the dengues and phlebotomus fevers which are endemic over large areas, frequently reaching epidemic proportions and lying in wait for the influx of non-immunes; to the constant threat and the seasonal : " recrudescence of the virus encephalitides, Eastern, Western and Venezuelan equine, and St. Louis in the Americas, and Japanese B and Murray Valley in the Far East and Australia; to the extension of the tick-borne viruses of the Russian spring-summer complex, the serious outbreak in the Kyasanur Forest district in India of a member of this group and the disturbing finding of a relative in Canada and the United States; to the vast and paralyzing epidemics of estimated millions of cases of Chickungunya and O'nyong-nyong fever in East AfrIca; to the appearance in the Philippines, Thailand and Singapore of a severe and frequently fatal epidemic hemorrhagic fever; and finally to the discovery of great array of previously unknown arthropod-transmitted viruses of potential threat to human health in the rain.forests of the tropical parts of the world.
We know a good deal about the ecology of some of these viruses; of others our knowledge is superficial, and of the large recently discovered group we know practically nothing, and probably, of none is our knowledge complete. In the explosive outbreaks, as for example urban yellow fever, the dengues, phlebotomus fever, etc., the cycle may be a simple one involving only man and a single species of vector. But in the cycles of most of these viruses man is not involved and his infection is tangential and fortuitous. Indeed, in most, if not all, instances the simple man-arthropod vector cycle is an aberrant one and the basic, more fundamental cycle is to be found embedded in the lower vertebrate fauna of the environment. It is this latter cycle that is an responsible for the survival and continuous maintenance of the virus. It should also be remembered that some of these viruses may be spread by winged insects and there is reason to believe, transported over long distances by bIrds and possibly bats, independent of the movements of man.
NEED FOR EXCHANGE OF INFORMATIONS
It must be obvious from the preceding discussion that for the coordinated and effective investigation of a problem, which by its very nature requires that studies be carried out in widely separated areas, the exchange of current information among the investigators becomes a matter of great concern. Not only do these viruses girdle the earth in their distribution, but it now appears that the endemic foci of many of them are to be found in distant parts of the world. It is frequently necessary to establish laboratories in isolated areas and the staffs represent a variety of disciplines in the biological sciences, such as medicine, entomology, ornithology, mammalogy and ecology. The literature having a bearing upon the natural history of the agents or vectors and hosts may appear in a variety of specialized journals not usually available except in in well-stocked libraries. A primary objective of the current program is to increase communication between the isolated workers and to increase the rapidity of dissemination of essential knowledge.
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The classification and the recognition of new species or types are at present based largely upon antigenic composition, utilizing rather recently perfected serological techniques. To accept a virus as a new species, it should be shown to differ significantly from all other previously isolated strains. This presupposes an awareness of all the previously isolated strains and, as a rule, the assistance of some central or reference laboratory in completing the necessary comparison: With the great increase in the number of recognized species or types, the identification of a virus as a new species becomes tedious and time-consuming.. This has contributed to the accumulation of many undescribed viruses, or, on the contrary, may result in premature publication.
To meet this contingency the creation of an arthropod-borne virus registry or catalogue was conceived. The idea being that a virus, which on presumptive evidence appears to represent hitherto undescribed member of the arthropod-borne family, can be registered pending more thorough study. Since similar viruses are frequently isolated in separate laboratories, some basis must be established which allows the early recognition of such similarities.
Equally important has become the currente exchange of information about the geographical known viruses, their arthropod and vertebrate host range, their behavior and usual life-cycles in different climatic and biological environments, as well as experiences in the application of new laboratory and field methods as developed and tried. It was proposed to accomplish this exchange of information through the medium of an informal Newsletter, periodically issued and distributed among the contributing participant.
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At the last meeting in April 1961 the loosely constituted Gould House Group was dissolved and a committee of six, of which Dr. W. C. Reeves is chairman, was appointed to assume its direcive and administrative functions. ThIs committee is designated as The American Committee on Arthropod-borne Viruses, under which the sub-committee on Information Exchange now serves.
THE ARTHROPOD-BORN VIRUS CATALOGUE
The purpose of the Catalogue as initially conceived vas two-foldÑto serve as a medium for notifying other investigators of a newly discovered virus, and to informally establish certain priority rights. Later, it was decided that in order to make the Catalogue more complete and to afford means of comparIson, the "old," or previously recognized viruses, should be included. However, the registration of "new" viruses is stiIl regarded as its primary and most useful function.
As was to be expected in devising the catalogue many questions arose, the most important of which were the criteria for inclusion of a virus in the Catalogue and the nature and. amount of information to be requested in its registration. It was easy to agree that the Catalogue should be limited to animal viruses bioIogically transmitted by arthropods and that each virus registered should represent a distinct species or type, or at least possess some distinctive characteristic differentiating it from other previously registered strains. But the criteria and the acceptable evidence for these qualifications are not so easily defined or obtained. However, it was decided that the function of the present sub-committee is to obtain and exchange information rather than to interpret and pass judgment upon it. It has been the policy, therefore, to accept a virus for regisation on presumptive evidence pending submission of additional information and review by a reference committee. While the Catalogue was originally planned for viruses infectious to man, any arthropod-borne animal virus entitled to registration. Indeed, effort has been made to have those of economic import in domestic animals registered.
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No stand is taken on nomenclature. All that is required is that a virus be given some specific and distinguishing designation, be it name or number. The name of the place or area where the first isolation was made is commonly used. Such names give an international flavor to the Catalogue.
A limited trial issue of the Catalogue, containing forty-seven registrations, was made in April, 1960. Since then the registration form has been revised and the number of registrations increased to 110. The second edition should be issued shortly and it is a.nticipated that it will include more than 130 registrations.
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NEWSLETTER
Under the able guidance of Dr. T.H. Work, the Newsletter has from the beginning met with favorable response. As stated of the cover it is issued "for the sole purpose of timely exchange of information among investigators of arthropod-borne viruses. It contains reports, summaries, observations, and comments submitted voluntarily by qualified agencies and investigators. The appearance of any of information, data, opinions, or views in this Newsletter does not constitute formal publication. Any reference to, or quotation of, any part of this Newsletter must be authorized directly by the person or agency which submitted the text. It is comprised of reports distributed by participants and to continue to receive the Newsletter, it is required to periodically send in a report. Administrators not personnally engaged in research but under whom research is being performed are alone exempted from this rule. Thus, it is entirely a means of informal and current exchange of information among those actively engaged in the study of arthropod-borne viruses, either in the laboratory or field.
Four numbers have been issued at approximately six months intervals. In the first three issues only Americans participated but the last number includes foreign participants. The selection of foreign participants and the method of communication with them are being developed in collaboration with the WHO. The selection is still proceeding. To date seventy-five investigators operating in thirty-seven different nations have been invited to participate. Sixty-six within the United States are participating, thus making at present a total circulation of 141.
ABSTRACT SERVICE
As an accessory and more general source of information, arrangements have been made to reproduce and distribute abstracts on the arthropod-borne viruses appearing in Biological Abstracts. The abstracts wiIl be reproduced on three by five inch paper slips, each slip carrying an index code and accompanied by a set of index cards. The index system uses as a frame-work the main rubrics in the Catalogue registration form to facilitate cross reference or inter-transfer of information.
SUMMARY AND DISCUSSION
If the ultimate objectives of research on arthropod-borne viruses are to control their propagation, prevent human infection, to anticipate their distant implantation and perhaps to do something to circumvent it, there must be a firm foundation of scientific information. The viruses must be readily identifiable. It must also be known where they are harbored, how they are maintained, their essential ecology including the animals and the arthropods involved, and the areas which are receptive to invasion by virtue of a favorable biological environment. To obtain this information a world-wide integrated program of surveillance and research is obligatory.
The Catalogue and the Newsletter are precursors in this program. They are both in the experimentaI and developmental stage and being cooperative projects their success will depend upon the sustained interest and support of the participants. It is hoped they will be instrumental in stimulating development of other features of the recommended international program.
In closing I shall assume the liberty of expressing a few thoughts on the outlook in combatting these viruses. The cycle which involves only man and an arthropod veetor may be effectively controlled or even eliminated as the vector is sure to be anthropophilic in feeding and preferences or domestic in its habits, frequently both, and is, therfore, vulnerablc to destruction. But to effectively combat the more basic cycles which may involve virtually all of the blood-sucking arthropods and warm-blooded vertebrates, and perhaps some of the cold-blooded ones also, is a formidable undertaking and requires a great deal more knowledge than we now possess.
It is recommended, therefore, that we foster the training of personnel in all of the disciplines that are involved in obtaining a better understanding of the nature and behavior of these parasites. There must be leadership, of course, there will be need for coordinated management but, above all, there will be required a vanguard of unassuming, dedicated and well- trained men and women with open and inquisitive minds,Ñvirologists and immunologists in the laboratory and far flung in tbe field, epidemiologists, ecologists and naturalists aided by entomologist, ornithologists and mammalogists. Each may carry only a candle, but if there are enough of them strategically placed and working together toward a common objective they may illuminate the path to wisdom. And in the meantime, please let us be humble rather in than boastful in predicting our accomplishments. For when we start tampering with nature on a massive scale we should know what we are about, lest we encounter some unexpected obstacles or some unanticipated results.