AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 68:495-498 (1985) Chagas’ Disease in Pre-Columbian South America FRANCISCO ROTHHAMMER, MARVIN J. ALLISON, LAUTARO NUNEZ, VIVIEN STANDEN, AND BERNARD0 ARRIAZA Department o f Cellular Biology and Genetics, University o f Chile, Santiago 7 (F: R.j, Institute of Anthropology and Archaeology, University of Tarapacd, Arica (M.J.A., VS., B.A.), and Department of Archaeology, Northern University, Antofagasta (LN.j, Chile ABSTRACT The quest for the origin and dispersion of Chagas’ disease, the second most important vector-borne disease in Latin America, has epidemiological, immunological, and genetical implications. Conjectures based on accounts of chroniclers, reviews of the archaeological literature and the present distribution of triatomine bugs, the vectors of the disease, held that the origin of the adaptation of Triatoma infestans (a species of the subfamily Triatominae) to human dwellings occurred in prehistoric times. The autopsy of 35 mummies exhumed in the Chilean desert, dated between 470 B.C. and 600 A.D., revealed the presence of clinical manifestations of Chagas’ disease and put earlier speculations on a factual basis. Chagas’ disease is, after malaria, the most prevalent vector-borne Latin American malady (Schofield et al., 1982). It was discovered by the Brazilian Carlos Chagas in 1909 (Leon, 1962) and is caused by the protozoan parasite Trypanosoma cruzi, which is commonly transmitted in the faeces of reduviid bugs of the subfamily Triatominae, but may also be conveyed by blood transfusion, congenitally, orally, or by organ transplant (Schofield et al., 1982). The most frequently encountered Triatominae in meridional South America belong to the species Triatoma infestans and are found in rural dwellings proliferating in the cracks of roofs and walls. Anecdotal information provided by chroniclers and naturalists suggests that the adaptation of T infestans to human habitats occurred before the sixteenth century. Among others, Fray Reginald0 de Lizarraga and Padre Bernabe Cobo, Spanish priests, noted the presence of blood-sucking bugs in Argentina, Bolivia, Chile, and Paraguay (Leon, 1962); and Charles Darwin mentioned having been attacked by the “benchuca” (vinchuca) in Argentina (Darwin, 1839). This term is derived from Quechua and still used to designate triatomine bugs in Andean countries (Carpintero and Viana, 1980). Recently, Carpintero and Viana (19801, on the basis of the aforementioned accounts as well 0 1985 ALAN R. LISS, INC. as on incomplete archaeological literature reviews and the present distribution of Tinfestans, speculated that the adjustment oftriatomine bugs to human dwellings took place in certain early agroceramic foci which emerged in the central sierras of Argentina around 500 A.D., as well as in southern Peru and eastern Bolivia. The ancient and widespread practice of Andean aborigines to raise guinea pigs (Cauiaporcellus)for consumption might have favored the adaptation of Triatominae to human habitats. These small rodents, as well as larger mammals such a s the American Camelidae, probably hosted l? infestans before becoming domesticated. The object of this report is to describe the results of the autopsies of Chilean mummies which revealed the presence of clinical manifestations of Chagas’ disease and to put, through the presented evidence, earlier speculations about the origin and dispersion of this disease on a factual basis. MATERIALS AND METHODS The arid northern part of Chile which extends from the Peruvian border to the Copiapo river, consists of a t least three ecogeographic areas, namely, the Andean highlands, the fertile transverse valleys and ravReceived March 26, 1985; revised June 28. 1985; accepted July 15, 1985. 496 F. ROTHHAMMER ET AL. ines, and the desert between the valleys. Vegetation in the valleys is correlated with humidity and includes such diverse plants as cattail (Scirpus californieus) and carob tree (Prosopisjuliflora). As part of a multidisciplinary research effort concerned with the early emergence of sedentarism in the Chilean desert, 35 mummies of four archaeological sites dated respectively with I4C at 470 B.C., 383 A.D., 290-360 A.D., and 600 A.D. (Nuiiez, 1982) were exhumed in Quebrada de Tarapaca (latitude 19" 57' S; longitude 69" 33' W; elevation 1,150 m). This is a small transverse valley that was peopled around 2850 B.P. by incipient agriculturalists who first built rectangular shelters and later dwellings from mud blocks, stone, and straw, providing ideal conditions for the adaptation of triatomine bugs. The mummified bodies were autopsied in search of mega-syndromes, which are the result of the denervation of the intraneural nervous plexus of hollow organs such as the colon, the heart or the esophagus caused by I: cruzi (Koeberle, 1956). Megacolon was diagnosed by relative size of colon and weight of coprolites, and cardiomegaly and megaesophagus by relative heart size and esophagus diameter. Diagnoses were performed by one of us (M.J.A.). Male and female age estimates were obtained according to methods described by Bass (1971). to have megacolon. A 20-25-year-old male had megacolon and megaesophagus and, finally, a 2%-half-year-oldboy exhibited megacolon and cardiomegaly. Among affected females were four mummies with megacolon aged, respectively, 12, 35-40, 40, and 50 years. Considering the above figures we tentatively estimated the prevalence of megacolon in pre-Columbian Chilean populations to be 41%. Similar estimates for cardiomegaly and megaesophagus are respectively, 9% and 4.5%. DISCUSSION It is unlikely that the megacolon cases discovered are attributable to aganglionic megacolon, since the rectum of megacolon mummies was distended with faeces, as opposed to the empty rectum found in Hirschsprung's disease (La Mont and Isselbacker, 1980). Moreover, congenital megacolon as well as chronic idiopathic megacolon and other forms of colon distention which are secondary to neurologic disorders, myxedema, amyloidosis, or scleroderma are very infrequent. It is interesting to note that in a recent survey conducted in Chile, consisting of the second largest series of patients of South America, 90% of subjects with megacolon and 100% of individuals with megacolon and megaesophagus turned out to be serologically Chagas' disease positive (Atias, 1980). In Chile, megacolon is approximately four times a s frequent as megaesophagus. In enRESULTS demic areas, roughly 34% of the population Table 1 reports the presence of megacolon, was found to be serologically positive. Some cardiomegaly, and megaesophagus in mum- 24% of positive individuals, roughly 8% of the population, develop cardiopathies (Arrimies of Quebrada de Tarapaca. Of 22 mummified bodies which were pre- bada et al, 1981). It has been suggested to us (P. Horne, perserved in sufficiently good conditions to assure accurate diagnosis, nine mummies sonal communication) that in unembalmed exhibited mega-syndromes. One 40-45-year- bodies following death, especially in a warm old male presented megacolon and cardio- climate, fermentation with gas production megaly. Three 45-year-old males were shown may cause expansion of intestinal walls, TABLE I . Megacolon, cardiomegaly, and megaesophagus in Pre-Columbiari mummies from northern Chile Pircas-2 Exhumed bodies Preserved bodies Megacolon present Cardiomegaly present Megaesophagus present 9 8 3 1 1 Archaeological site Caserones-SUR Tarapaca-40A 13 4 1 11 9 - - - 4 1 Tarapaca-0 Total 2 1 1 35 - 22 9 2 1 CHAGAS’ DISEASE IN PRE-COLUMBIANSOUTH AMERICA which followed by rapid dehydration, could in turn produce pseudomegacolon. The fact that the colons of the mummies were packed with coprolites makes this explanation unlikely. Also, the expansion due to gas from ingestion of beans, i.e., Phaseolus lunatus, is not supported by analysis of coprolites, which contained carob tree sheaths, i.e., Prosopis juliflora. It has been indicated, furthermore, that high altitude can eventually cause megacolon (Frisancho, 1974). Consequently, some mummies with megacolon could have been migrant highlanders. This conjecture would, however, imply that an unusually high proportion of the prehistoric inhabitants of Tarapaca valley were recent migrants and that megacolon was exceptionally frequent in the highlands. It is worth mentioning in this context, that only one megacolon case was found in Azapa valley, some 150 km north, among roughly 500 mummies autopsied. The prehistoric populations of both valleys were, however, exposed to the same highland penetration since around 1000 B.C. (Nufiez, 1983). Cardiomegaly has been interpreted by us elsewhere as an indicator of highland birth (Fontana et al., 1983). However, both cardiomegalic males presented histopathological evidence of fibrotic changes in the myocardial tissue which cannot be attributed to high altitude. Finally, our finding of a case of megaesophagus, added to the previously discussed evidence, strongly suggests that Chagas’ disease was present in northern Chile before 500 B.C. Although our estimates of the prevalence of megacolon, megaesophagus, and cardiomegaly in pre-Columbian populations may be biased as a result of the excavation procedures, we note that our figures are similar to those presently encountered in endemic areas of Chile. The transition from a hunting-gathering to a transitory and subsequently permanent sedentary stage was probably accomplished by Paleoindian hunters in the Pampa de Junin, central highlands, some 6,000 years ago (Wheeler et al., 1976). Permanent dwellings of stone or mud block (adobe)walls and straw roofs were built as early as 3000 B.C. in the central highland and on both the eastern and western slopes of the southern Andes (Nuiiez, 1983). Archaeological evidence indicates that the Quebrada de Tarapaca was initially peopled 497 by small bands of migrants from the southern highlands, specifically from the shores of Lake Poopo, as judged by the presence of ceramic fragments and other cultural artefacts belonging to the Wankarani, a culture that established itself around 1200 B.C. (NUiiez, 1982). It is hypothetically possible that before becoming sedentary, Andean Paleoindians acquired Chagas’ disease by ingesting raw infected meat of Camelidae, Cervidae, or small rodents, which have probably hosted T infestans since before the Pleistocene (Neghme, 1982) and which were found associated with Paleoindian archaeological sites (Dauelsberg, 1983). Furthermore, given the opportunistic nature of Triatominae, it may also be speculated that triatomine-mediated transmission started with human occupation of caves and rock shelters. We suggest, however, that the increase of prevalence of the disease to endemic levels, occurred most probably after the adaptation of T infestans to permanent human dwellings in the central and southern highlands before 500 B.C. ACKNOWLEDGMENTS This work was supported by grants 825991 UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, B-518-845F, D.I.B., University of Chile, and 01068 Fondo Nacional de Ciencias, Conicyt, Santiago. We are indebted to Prof. T. Pizzi for the histopathological analysis of myocardial tissue. Comments of M. Diaz, L. Eaton, G. Hoecker, and C.Y. Valenzuela are gratefully acknowledged. LITERATURE CITED Arribada, A, Apt, W, Ugarte, JM,An-ibada, AM, and Sandoval, J (1981)Epidemiologiade la cardiopatia chagasica en Chile, Rev. Med. Chile 109:1199-1207. Atias, A (1980) Enfermedad de Chagas digestiva en Chile, experiencia de 20 aiios. Bol. Hosp. S.J. Dios 27:251-257. Bass, W M (1971) Human Osteology. 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