Global Epidemiology Today

In presenting some thoughts on perspectives in global epidemiology, I want to emphasize that we are dealing with a moving picture that changes not only from place to place, but also in time over the centuries, year by year, and even day by day. Imagine the evolution of the world, speeded up so that years pass in seconds, and centuries in minutes. Far back in history there were small foci of human activity about which we know little. Gradually these foci extended and in certain areas there were sudden increases which were the early great civilizations. Imagine the thriving, bustling life in these early cities, confident in the future, when suddenly something happened and it disappeared. In the time scale we are imagining, in a few seconds or a minute or so there is nothing left except stones and bones for archeologists. What happened? In most instances we do not know precisely. Sometimes it was doubtless the depredations of neighboring groups, more virile and aggressive, but without the knowledge or intellectual capacity to maintain and continue the development of the civilization they had conquered. Sometimes the civilization destroyed or damaged itself unwittingly by its interference with the ecological situation in which it existed. Irrigate and build reservoirs, and you build breeding places for mosquitoes. Malaria may destroy a civilization, as is believed to have happened in Ceylon. Build houses with cellars and unprotected grain stores-domestic rodents will increase, and plague and typhus will follow. Ship negro slaves across the Atlantic for profit-their viruses travel with them, and the planters purchase Yellow Jack as well as labor. Medical historians can certainly provide many other examples of the results of man's ignorance. And ignorance is, in the long run, more dangerous than aggression. The examples I have given are well known, and we do our best to avoid such risks. But what of the unknown or unrecognized dangers we are facing now? The changes in man's ecology which have taken place in the last century have been greater than the previous changes in the whole of man's known history. I use the word changes rather than the word progress deliberately. Only the future will show whether we have made progress or whether we are building something that may eventually destroy us. I believe * Chief Medical Officer, Virus Diseases.