2 • Introduction 



classifying what we observe are important. However, this 

 objective must be achieved within the framework of princi- 

 ples of descriptive and classificatory rigor that are well 

 known and established in other biological and medical disci- 

 plines. 



We must also move beyond description and classification 

 and ask "what does it mean?" In the context of this question, 

 theory, including both medical and biological, is critical. 

 Theoretical questions in paleopathology abound and are 

 largely unanswered. For example, is evidence of disease in 

 archeological bone tissue indicative of the fact that the indi- 

 vidual had poor health during life? This question must be 

 evaluated in comparison with an individual that has no skele- 

 tal indicators of disease. Does dental hypoplasia reflect simi- 

 lar disease conditions and processes as those that produce 

 lesions in bone tissue? 



We also need a much stronger theoretical base on the evo- 

 lution of disease and the dynamics of host/ vector interaction 

 through time. BrothwelFs report on animal/human interac- 

 tion in the transmission of disease in this volume offers in- 

 sight and raises important questions on this issue. Clearly 

 there is a dynamic relationship between the evolution of in- 

 fectious agents and the immune response of individuals in the 

 host population through time (e.g., Cockbum 1963; Fiennes 

 1978). Infectious agents tend to become less virulent and the 

 immune response of the host-population improves with se- 

 lective evolutionary processes affecting both the agent and 

 the host. However, what are the evolutionary mechanisms 

 when the interaction between the infectious agent and the 

 host is indirect. This appears to be the case in some of the 

 erosive joint diseases where an infectious triggering agent 

 initiates a genetically defective immune response that results 

 in disease. 



Other theoretical issues include a careful understanding of 

 what constitutes disease versus what constitutes a dysfunc- 

 tional biomedical response. For example, we have known for 

 some time that, in some environmental situations, disease 

 may have a net benefit. Sicklemia in Africa and thalassemia 

 in the Mediterranean region represent a biological adaptation 

 to endemic malaria that has a net functional value despite the 

 serious, generally fatal anemia that is associated with the 

 homozygous expression of the disease. Stuart-Macadam 

 suggests, in her report in this volume, that iron deficiency 

 anemia may reflect a functional response to other infectious 

 diseases. As we develop theory in paleopathology that inte- 

 grates information from several disciplines, we need to in- 

 sure that our terminology does not limit our interpretative 

 options; that is, evidence of disease may, in fact, be indica- 

 tive of adaptive biological responses to probleins. 



The role of population density in disease is another impor- 

 tant theoretical question. We know very little about the rela- 

 tionship of population density and disease in antiquity. For 

 example, at what point in human history did viruses become 



a significant source of disease? Some viral infectious dis- 

 eases require substantial population sizes and densities for 

 maintenance (Fiennes 1978:20). McGrath's( 1 986) computer 

 simulations suggest that some infectious diseases (e.g., hu- 

 man tuberculosis) could not have been maintained in pre- 

 historic Native American populations. This observation is in 

 apparent opposition to paleopathological evidence that tuber- 

 culosis was in fact present well before the 15th century. Are 

 theoretical models ba.sed on modem medical experience ap- 

 plicable to conditions extant in living archeological human 

 populations? 



Related to this question is the important issue of whether or 

 not paleoepidemiological research is possible with archeo- 

 logical materials. Certainly one of the goals for paleopathol- 

 ogy should be the establishment of epidemiological trends in 

 antiquity. There clearly are theoretical and methodological 

 limitations in doing this. We need to establish the potential as 

 well as the limitations of paleoepidemiology. 



We know very little about the impact of culture change on 

 human health. For example, what effect did rapid and trau- 

 matic social change have on historic Native Americans? Is 

 the apparent increase in infectious disease in these people due 

 to exposure to new diseases for which they had minimal 

 immunological experience and response or are social- 

 psychological and other factors contributing as well? In try- 

 ing to organize the topics and themes for the symposium, we 

 have encouraged the authors of papers to review the status of 

 research in their areas of special research interest. This re- 

 view raises many questions about the nature and value of 

 research conducted thus far. Asking good questions is the 

 first step in getting good answers and making informed deci- 

 sions about future research. Both reviewing the current status 

 of research in paleopathology and exploring future options 

 were objectives for the symposium and the published papers. 

 A careful look at where we now are in paleopathology pro- 

 vides the basis for a more informed process of choosing 

 among the options for future research. We hope that we have 

 been at least partially successful in achieving this objective. 



Literature cited 



Cockbum. A. 1963. The Evolution and Eradication of Infectious 

 Diseases. Baltimore: Johns Hopkins University Press. 



Fiennes, R.N. 1978. Zoonoses and the Origins and Ecology of 

 Human Disease. New York: Academic Press. 



Grmck, M.D. 1989. Diseases in the Ancient Greek World. Bal- 

 timore: Johns Hopkins University Press. 



McGrath, J.W. 1986. A Computer .Simulation of the Spread of 

 Tuberculosis in Prehistoric Populations of the Lower Illinois 

 River Valley. Ph.D. dissertation. Northwestern University. Evan- 

 ston. III. 



McNeill, W.H. 1976. Plagues and Peoples. Garden City. N.Y.: 

 Anchor Press/Doubleday. 



Zagreb Paleopatttology Symp. 19HH 



