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Mem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 98(Suppl. 1), January 2003, pp. 1-2 Foreword C Combes Université de Perpignan, Laboratoire de Biologie Animale, UMR5555 du CNRS, Perpignan, France Code Number: oc03001
Living organisms appeared nearly 4 billion years ago, probably in aquatic environments of our developing planet. Much time later on they were capable of adapting to terrestrial environments and this adventure continued till the appearance of human conscience. But it is infinitely probable that, since the beginning, living organisms had conquered a third type of environment: the living environment itself. Thus parasitism had appeared... It was an unfailing success throughout evolution up to the present day, for a host offers a habitat, a permanent source of food, and an efficient mechanism of dispersion to every organism which knows how to exploit it. In the present world parasitic and infectious diseases remain fearsome calamities for humans and domestic animals, whereas even predators are no longer a danger. The reasons for the enduring success of all kinds of parasitism are multiple: one of them is that it is much easier for a free-living organism to detect a predator approaching than an infective stage of a parasite; another is that parasites, thanks to their short generation time and their constantly renewed genetic diversity, are remarkably adapted to escape host immunological defenses. However, there is no doubt that the most rational explanation for the large number of parasitic diseases that affect humans and stock animals is to be found in the evolution of human behavior itself. Since hominid emergence in the remote past somewhere in the Old World, our ancestors have never stopped conquering new ecosystems and diversifying their ways of life. Humans have eaten new kinds of food and increasingly occupied wetland environments, resulting in exposure to parasites that had evolved in other hosts. In becoming commensals of some species and having domesticated others, humans have allowed parasites to pass from animals to man. Social life, already existent among other primates but extremely intense among humans, could only favor the transmission of many parasites. This is why, during a few hundreds of thousand years, a new history of parasite-host relationships was written, that of the invasion of man by a very large number of parasites. At the same time, attempts to control parasitic diseases may have existed, but these attempts were almost always bound to fail, until science became involved. The history of the relationships between man and parasites is both dramatic and riveting. Dramatic as it has undoubtedly restrained for thousands of years the demographic expansion of our species. Riveting as it is part of the finest chapters on the interactions between species during the course of evolution. As a young discipline, paleoparasitology aims to reconstitute this history of parasitism. Such an undertaking is terribly difficult as the evidence is rare and the interpretations are not easy. But it is an undertaking in full development and the results are more numerous and more reliable each year. While for almost two centuries life sciences and human sciences have had many difficulties in communicating between themselves, paleoparasitology shows the way by dialoguing with disciplines such as paleontology, archaelogy, history, human and veterinary medicine, epidemiology, palynology, geography, molecular biology, and genetics. Paleoparasitology thus raises the curtain on the biotic factor which has probably exercised the strongest selective pressures on human populations, either during prehistoric or historic periods. These selective pressures have sorted out the fittest or the luckiest, with no consideration of their global selective value. This is a tragic illustration of the short-sightedness of natural selection that has killed Alexander the Great and Mozart, and even earlier tens of thousands of people who would have brought a contribution to the culture of emerging humanity. For one artist who has lived long enough to paint the frescos of Lascaux, how many have died prematurely, victims of parasitic diseases for which they could not even imagine the origin? The present book appears at the right time to provide a state of the art in paleoparasitology. Archaelogists, prehistorians, historians and biologists will find the most recent techniques, up-to-date results and the latest perspectives. In these first years of the 3rd millenium, this collection of knowledge constitutes a solid framework upon which the future of paleoparasitology can be based. C Combes Copyright 2003 Instituto Oswaldo Cruz - Fiocruz |
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