Scanning Electron Microscopy in Paleoparasitology: A New Technique for Old Questions. J.M.F Dutra-Santiago 1 , L. Sianto 1 , R. Rachid 2 , W. De Souza 2 and A. Araújo 1 *. 1. Escola Nacional de Saúde Pública Sérgio Arouca , Fundação Oswaldo Cruz , Rua Leopoldo Bulhões 1480, Manguinhos, Rio de Janeiro, Brazil, 21041-210, tel: +55 21 2598-2566. *Email: adauto@ensp.fiocruz.br 2. Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho s/n, 21941-902, Ilha do Fundão, Rio de Janeiro, RJ, Brazil. Paleoparasitology research emerges as a new branch of science discussing the antiquity of host- parasite relationships and how they evolved from past until today. Since the first record of parasites in coprolites [1] until recent findings [2] optical microscopy is the main tool for diagnosis. Although 50 years have elapsed since the first publication, few works showed results using electron microscopy for coprolites analysis. Shin and colleagues [3] conducted a scanning electron microscopy (SEM) study on ancient Trichuris trichiura eggs recovered from Korean mummies of the Joseon Dynasty. In the present work we conducted SEM study using coprolites from animal and human origins, proposing a new methodology to desiccated samples. Coprolites from animal origin were collected at Toca dos Coqueiros, National Park of Serra da Capivara, São Raimundo Nonato, Piauí state – Brazil (Figure 1). Coprolites were identified from Tamandua tetradactyla origin and dated 8870±60 years BP. The human coprolite was from a priest mummy housed in the Piraino Cathedral in the province of Messina, north-east Sicily, Italy. For Scanning Electron Microscopy, small pieces of coprolites were crushed using a glass stick, inside a Petri dish. The pieces became a mixture of different grain sizes that were separated using a stereomicroscope (Carl Zeiss). The smallest grains were set apart with a paintbrush and mounted on scanning electron microscope stubs with double- sided carbon tape (Ted Pella, Inc.), sputter-coated with gold and examined under a scanning electron microscopy - Quanta 250 (FEI Company). Both animal and human coprolites were observed using the new technique and showed a good result for paleoparasitological analysis. Both samples were observed, measured and compared with bright field microscope images (Figure 2 and 3). Besides the dried condition for SEM observations, we were able to identify eggs from Acanthocephalan specie and Trichuris trichiura. We conclude that SEM technique is a powerful tool that can be used to identify and help paleoparasitological research. References [1] L.F Ferreira, A.J.G Araújo, U.E. Confalonieri. Subsídios para a paleoparasitologia do Brasil – I. Parasitos encontrados em coprólitos no município de Unaí, MG. Resumos do IV Congresso Brasileiro de Parasitologia, (1979) 56. [2] M.H. Fugassa, K. Reinhard, K.L. Johnson, S.L. Gardner, M. Vieira, A.J.G Araújo. Parasitism of prehistoric humans and companion animals from Antelope Cave, Mojave County, Northwest Arizona. J Parasitol. (23) (2011) In press. [3] D.H. Shin, D.S. Lim, K.J. Choi, C.S. Oh, M.J. Kim, I.S. Lee, S.B. Kim, J.E. Shin, G.D. Bok, J.Y. Chai, M Seo. Scanning electron microscope study of ancient parasite eggs recovered from Korean mummies of the Joseon Dynasty. J Parasitol. 95(1) (2009) 137. [4]We thank Dr. Niéde Guidon, from the Fundação Museu do Homem Americano, Piauí state, Dr. Dario Piombino-Mascali, from of the Istituto per le Mummie e l'Iceman and Dr. Karl Reinhard, from University of Nebraska, USA, for the samples examined. [5] This research was supported by CNPq and CAPES/FAPERJ (Brazil).