Trends and perspectives in paleoparasitological research • 77 



However, for the assessment of the origin of coprolites we 

 must not forget other parameters, such as their food content 

 as well as parasite composition known to be typical for the 

 human host. Such parameters also include biochemical stud- 

 ies which, although still in their infancy, certainly became an 

 important option after the identification of steroids from 

 2000-year-old North American coprolites (Lin et al. 1978). 



A second problem relates to the possible structural modi- 

 fications found in parasites contained in fecal material from 

 archcological sites. Under the influence of environmental 

 factors, parasite remains could undergo deformities and/or 

 size modifications making their identification difficult or 

 even impossible. Such physicochemical processes could de- 

 stroy parasitic forms in the fecal mass; these phenomena 

 seem to be responsible for the scarcity of findings of pro- 

 tozoan cysts in coprolites. The first attempt to solve this 

 problem came from the experimental approach inaugurated 

 by Adamson (1976) when he assessed the persistence of eggs 

 of Schistosoma sp. in artificially desiccated tissues in order to 

 evaluate the actual frequency of these findings in Egyptian 

 mummies. This approach was then extended to several nor- 

 mal tissues as well as to soft tissue lesions (tumors, for exam- 

 ple) by Zimmerman (1972,1977,1978) in an effort to assess 

 the possibilities of histopathological diagnosis in mummified 

 bodies. More recently we started to study the morphological 

 modifications which occurred in helminth eggs and larvae 

 after artificial desiccation and rehydration of fresh feces 

 using different techniques. We have tested whether helminth 

 eggs, such as those of the nematode genus Trichuris sp. 

 (Confalonieri et al. 1985) and ancylostomids (Araujo 1987), 

 whose diagnosis depends not only on qualitative mor- 

 phological characteristics but also on size variations, would 

 undergo significant alterations in their dimensions. 



So far these experiments have demonstrated that the desic- 

 cation process does not cause deformities in these biological 

 structures that would hinder an adequate identification. 



Finally, detailed morphologic study of parasites found in 

 ancient material should be considered in qualitative as well as 

 in quantitative aspects. In the former case, the differential 

 diagnosis rests on detectable microscopic differences of 

 closely related taxa. For this purpose the best technique is 

 scanning electron microscopy, which can reveal variations in 

 the surface relief of eggs and larvae of helminths. A com- 

 parative morphological study using this technique is pres- 

 ently underway in our laboratory. It focuses on larvae of 

 Ancylostomu duodenale and Necator americanus, the most 

 common human hookworms whose desiccated forms cannot 

 be easily separated with the light microscope. 



Diagnosis of some parasites depends on biometric evalua- 

 tion. This includes the ova of Trichuris, the helminth most 

 commonly found in South American coprolites, but also very 

 common in European archcological deposits. These are 

 being studied with some taxonomic techniques, such as the 

 Student t-test, for small samples (Sokal and Rohlf 1969:223). 



The test was applied to the identification of eggs of this genus 

 from small fragments of coprolites from South American 

 sites (Confalonieri 1988) under circumstances in which mor- 

 phological criteria to the identification of the fecal material 

 cannot be used. In such cases in which several species of 

 Trichuris have overlapping size ranges, including the human 

 T. irichiura, the statistical procedure is useful since it indi- 

 cates in probabilistic terms the possibility for human origin of 

 the material. 



We are using, again with Trichuris eggs, a new biometric 

 parameter for a better discrimination of the different species. 

 This is the linear regression coefficient between length and 

 width of the eggs, already used by Joyner and Norton (1980) 

 in the specific diagnosis of protozoan oocysts. Thus we can 

 add another variable for a more complete morphological 

 evaluation of the egg of each species. This parameter was 

 shown to be especially useful for the differential diagnosis of 

 eggs of T. Irichiura and T. suis. two sister species commonly 

 associated in archcological material from Europe (Jones 

 1982). 



In summary, advances in techniques and methods applied 

 to paleoparasitological investigation are the result of new 

 approaches from biomedical and zoological sciences. In the 

 future these will provide a greater reliability for identification 

 of parasitic diseases in pre- and protohistorical populations. 



Literature cited 



Adamson, P.B. 1976. Schistosomiasis in Antiquity. Medical Histo- 

 ry. 20:176-188. 



Araujo, A.J.G. 1987. Paleoepidemiologia da Ancilostomose. 

 D.Sc. dissertation, Ensp, Fiocruz, Rio de Janeiro. 



Baer, J.G. 1971. Animal Parasites. New York: McGraw-Hill. 



Confalonieri, U.E.C. 1988. The Use of Statistical Test for the Iden- 

 tification of Helminth Eggs in Coprolites. Paleopathology News- 

 letter. 62:7-8. 



Confalonieri, U.E.C, B.M. Ribeiro-Filho, L.F. Ferreira, and 

 A.J.G. Araujo. 1985. The Experimental Approach to Paleo- 

 parasitology: Desiccation of Trichuris irichiura Eggs. Paleo- 

 pathology Newsletter. 5 1 :9- 1 1 . 



Fferreira, L.R, A.J.G. Araujo, U.E.C. Confalonieri. 1979. Sub- 

 si'dios para a Paleoparasitologia do Brasil I. Parasites En- 

 contradosemCoprolitos noMunicipiodc Unaf. MG.ResumoslV 

 Congresso Sociedade Brasileira Parasitologia. Campinas. 



Fry, G.F. 1977. Analysis of Prehistoric Coprolites from \Jli\\. An- 

 thropological Papers, vol. 97. University of Utah. 



Home, P.D. 1986. Helminthiasis and Mummified Human Re- 

 mains. Abstract. 13th annual meeting of the Paleopathology As- 

 sociation, Albuquerque. New Mexico. 



Jones. A. KG. 1982. Human Parasite Remains: Prospects for a 

 Quantitative Approach. In A.R. Hall and H.K. Kenward, eds.. 

 Environmental Archeology in the Urban Context. Council for 

 British Archeology Research Report. 43:66-70. 



Joyner. LP., and C.C. Norton. 1980. The F.imeiha acer\'ulina 

 Complex: Problems of Differentiation of Eimeria acenulina. E. 

 mitis and E. mivali. Protozoological Abstracts, 4:45-52. 



Zagrrb Paleopathology Symp. 1988 



