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Radiocarbon dates and the history of treponematoses in man
Journal of Archaeological
Science 1975, 2, 393-396
Radiocarbon Dates and the History of Treponematoses in Man Don Brothwell Institute qf Archaeology, Gordon Square, London WCl, England and Richard Burleigh Research Laboratory, The British Museum, London WCl, England
There is still considerable uncertainty as to the antiquity of bone-changing treponemal disease in man. Goff (1967), Henschen (1966) and others would accept a yaws/syphilis treponeme in the New World prior to European contact. Hackett (1963) would argue, especially on historical geographic and clinical evidence, that bone-modifying treponemes originated first in the Old World-venereal syphilis particularly evolving early in the Mediterranean area. Clearly, further progress in studying the micro-evolution of earlier treponeme variaties in relation to evolving and dispersing human communities, depends on their identification in well-dated osteological material. Brothwell (1970) has already argued, on the basis of limited archaeological evidence, for pre-Columbian treponematosis in both Eastern Asia and the New World. Dating some of these controversial specimens is especially a problem in relation to material from the Americas and for this reason it would seem particularly worthwhile to establish where possible absolute dates for the bone pathology. Only by this means can we establish beyond reasonable doubt the considerable antiquity of a yaws/syphilis type of treponeme in the New World and consider possible adaptive changes to varying environments. So far, the radiocarbon dating technique has established the considerable antiquity of the Indian Knoll population in Kentucky (C-254: 5302&3OO bp; Libby, 1952), where at least two skeletons show lesions (Snow, 1948) which could be interpreted as indicative of a bone-destructive treponematosis. Radiocarbon dates have also been important in providing an absolute date range for the cultural sequences established for the Tehuacan Valley (Johnson & MacNeish, 1972). During the Santa Maria phase, (c. 900-200 bc) at least one individual displayed a highly destructive osteitis of the cranial vault of a kind typical of treponematosis. Materials for analysis
Following a visit by one of us (DRB) to the U.S.A. for the purpose of surveying Amerindian palaeopathology, it became clear that high priority should be given to associating more radiocarbon dates to pathology of special interest. Where sufficient skeletal material remains and preservation is such that sufficient bone collagen is likely to be present, the most reliable dating is clearly directly on the human remains. By this means, problems of intrusive burials or incorrect associations of osteological and cultural material are eliminated. Although the list might eventually be extended, we selected on the evidence of pathology and availability of bone samples the following sites for radiocarbon study. 393
394
D. BROTHWELL
AND
R. BURLEIGH
(1) Ser. I. 83. 4434. Californian Amerindian of Late Horizon date (i.e. within the range c. 300-1500 AD) Berkeley collection. Possible evidence of treponemal infection associated directly with this specimen. (2) May’s Lick, Kentucky. 20/915. “Prehistoric” Amerindian. A.M.N.H. collection, New York. At least nine individuals displayed vault changes which might indicate treponematoses. (3) Horr’s Island, Florida. Parts of two Amerindian skeletons: 352156 and 352162. Smithsonian collection, Washington. “Late prehistoric”. A number of specimens (but not these) in the collection displayed osteitic changes which could be of treponemal origin. (4) Cco. 138. 6091. Californian Amerindian of Late Horizon date. Berkeley collection. This specimen provides further direct skeletal dating evidence for Late Horizon people. In terms of pathology, this individual displays evidence of spinal osteitis not indicative of a treponemal infection but probably of tuberculosis (another disease of controversial pre-Columbian antiquity). Further details of these specimens will be presented in a review article (by DRB) appear in a subsequent issue of this journal.
to
Results Five radiocarbon dates have been obtained by the British Museum laboratory for bones (femora) from the Amerindian skeletons listed above. The results of the radiocarbon measurements are given in Table 1. In line with the usual practice when dating bone, only the collagen content of these samples was used. Collagen is generally accepted to be the most reliable component of bone for radiocarbon dating, dates on whole ancient bone tending to be too young because the inorganic carbonates in the structure readily undergo exchange with atmospheric carbon dioxide or with bicarbonates in ground-water. As an organic substance collagen is not subject to such exchange processes and can be completely freed from the mineral constituents of bone by controlled soaking in dilute acid. The dates were obtained by liquid scintillation counting of benzene synthesized from the individual pure collagen samples, and have all been corrected for isotopic fractionation. The laboratory and computational methods used are fairly standard among radiocarbon dating laboratories and have been described in detail elsewhere (Burleigh et al., in press). Table 1. Radiocarbon and absolute dates for Amerindian human skeletal material showing evidence of special pathology
BM-no.
Sample
462
Californian Ser. I. 83. 4434 Californian Cco. 138. 6091 May’s Lick 201915 Horr’s Island 352156 Horr’s Island 352162
463 464 465 466
Radiocarbon date bp (1950)
Calendar date BP (1950) AD
Years before Columbian contact
857& 52
845+
65 1105
387
622& 63
625i
69
1325
167
563+104 735& 83
580+108 730& 92
1370 1220
122 272
852&120
845hl26
1105
387
TREPONEMATOSES
IN MAN
305
In Table 1 the dates given in radiocarbon years before present (bp) are based on the conventional 5570 year half-life for i4C. The associated error terms are derived from counting statistics alone and are equivalent to one standard deviation (I a). This is the usual mode of expression of “raw“ radiocarbon dates. Past variations in the level of natural 14C such that radiocarbon and calendar years are not necessarily directly equivalent are now well attested (see, for example, Olsson, 1970) but the differences are not large in the period in which these particular dates fall and can almost be disregarded here. However, in the interest of greater absolute accuracy, the estimated equivalent calendar dates (denoted BP/AD) are also given in the Table and these allow both for natural l4C variations, using the data of Damon et al. (1972) and the more accurate “new” half-life value for l4C (5730 years). As far as the measurements considered here are concerned the combined effect of these two corrections is small so that the final dates remain practically unchanged although it will be seen that the associated error terms are slightly increased, reflecting uncertainties in the calibration data. Closely similar results would be obtained by using other current radiocarbon calibration relationships (for example, the MASCA tables of Ralph ef al., 1973). From the results it can be concluded that all the dates obtained in this study would appear to be fairly certainly pre-Columbian with the possible exception of the May’s Lick sample (BM-464). Nevertheless, it should be noted that the estimated date for the May’s Lick sample is also some time before Columbian contact and only the relatively large error term of this measurement dictates the need for greater caution in its interpretation. It would obviously be desirable to add further samples to this series of measurements so as to provide enough values for a rigorous analysis to be made of their distribution in time. Conclusions
In an endeavour to clarify a little the pre-Columbian antiquity of treponematoses in the New World, human bone samples were submitted for radiocarbon analysis. Except for Cco. 138.6091, these specimens were in all cases from cemeteries which had produced bone pathology suggesting a treponemal disease. It was not possible in two cases (Horr’s Island samples) to date bone specifically from the pathological specimens, but it seems likely that there was reasonable contemporaneity with those tested. The radiocarbon results give strong support to the view that late pre-Columbian Amerindian communities in various parts of the U.S.A. at least were well acquainted with one or other bonemodifying treponemal infection. It might, of course, still be argued that contact with the Old World could have occurred some centuries earlier-to the extent of providing a corridor for the passage of such a disease type-but it must also be remembered that there is not certain osteological evidence of a treponemal disease in the European area prior to the sixteenth century. Moreover, the evidence from the radiocarbon dated material from Indian Knoll and Tehuacan seems to establish a very considerable antiquity for these micro-organisms in the New World, even if during these earlier phases the disease was restricted in extent. Acknowledgements
We wish to express our thanks to all those in the Lowie Museum of Anthropology at Berkeley, the Smithsonian Institution of Washington and the American Museum of Natural History in New York, who were in any way drawn into considering or despatching our specimen needs. We wish to express special thanks to Professor Robert Heizer, Dr J. Lawrence Angel, and Professor H. Shapiro who were initially approached for help.
D. BROTHWELL
AND R. BURLEIGH
The radiocarbon samples were kindly prepared and measured by Mr A. D. Hewson and Mr N. D. Meeks of the British Museum Research Laboratory. References Brothwell, D. R. (1970). The real history of syphilis. Science Journal 6, 27-32. Burleigh, R., Hewson,A. & Meeks, N. (1976). British Museumnatural radiocarbon measurements VIII. Radiocarbon 18 (1) (in press). Damon, P. E., Long, A. & Wallick, E. I. (1972).Dendrochronologiccalibration of the carbon-14time scale.In (T. A. Rafter & T. Grant-Taylor, Eds.), Proceedings of the 8th International Conference on Radiocarbon Dating. Wellington: Royal Society of New Zealand, Vol. 1, pp. A29-43. Goff, C. W. (1967).Syphilis. In (D. Brothwell & A. T. Sandison,Eds.), Diseases in Antiquity. Springfield: Thomas, pp. 279-294. Hackett, C. J. (1963).On the origin of the human treponematoses. Bulletin of the World Health Organization 29, 741. Henschen,F. (1966). The History of Diseases. Harlow: Longmans. Johnson,F. & MacNeish, R. (1972). Chronometric dating. In (F. Johnson,Ed.), The Prehistory of the Tehuucan Valley. 4. Chronology and Irrigation. Austin: University of Texas Press,pp. 3-55. Libby, W. F. (1952). Radiocarbon Dating. Chicago: Chicago University Press,p. 78. Olsson,I. U. (Ed.) (1970).Radiocarbon Vuriations and Absolute Chronology. New York: John Wiley. Ralph, E. K., Michael, H. N. & Han, M. C. (1973).Radiocarbon datesand reality. MASCA Newsletter 9 (l), l-20 (Philadelphia,University Museum). Snow, C. E. (1948).Indian Knoll skeletonsof Site OH2, University of Kentucky Reports in Anthropology IV, 377-554.
Science 1975, 2, 393-396
Radiocarbon Dates and the History of Treponematoses in Man Don Brothwell Institute qf Archaeology, Gordon Square, London WCl, England and Richard Burleigh Research Laboratory, The British Museum, London WCl, England
There is still considerable uncertainty as to the antiquity of bone-changing treponemal disease in man. Goff (1967), Henschen (1966) and others would accept a yaws/syphilis treponeme in the New World prior to European contact. Hackett (1963) would argue, especially on historical geographic and clinical evidence, that bone-modifying treponemes originated first in the Old World-venereal syphilis particularly evolving early in the Mediterranean area. Clearly, further progress in studying the micro-evolution of earlier treponeme variaties in relation to evolving and dispersing human communities, depends on their identification in well-dated osteological material. Brothwell (1970) has already argued, on the basis of limited archaeological evidence, for pre-Columbian treponematosis in both Eastern Asia and the New World. Dating some of these controversial specimens is especially a problem in relation to material from the Americas and for this reason it would seem particularly worthwhile to establish where possible absolute dates for the bone pathology. Only by this means can we establish beyond reasonable doubt the considerable antiquity of a yaws/syphilis type of treponeme in the New World and consider possible adaptive changes to varying environments. So far, the radiocarbon dating technique has established the considerable antiquity of the Indian Knoll population in Kentucky (C-254: 5302&3OO bp; Libby, 1952), where at least two skeletons show lesions (Snow, 1948) which could be interpreted as indicative of a bone-destructive treponematosis. Radiocarbon dates have also been important in providing an absolute date range for the cultural sequences established for the Tehuacan Valley (Johnson & MacNeish, 1972). During the Santa Maria phase, (c. 900-200 bc) at least one individual displayed a highly destructive osteitis of the cranial vault of a kind typical of treponematosis. Materials for analysis
Following a visit by one of us (DRB) to the U.S.A. for the purpose of surveying Amerindian palaeopathology, it became clear that high priority should be given to associating more radiocarbon dates to pathology of special interest. Where sufficient skeletal material remains and preservation is such that sufficient bone collagen is likely to be present, the most reliable dating is clearly directly on the human remains. By this means, problems of intrusive burials or incorrect associations of osteological and cultural material are eliminated. Although the list might eventually be extended, we selected on the evidence of pathology and availability of bone samples the following sites for radiocarbon study. 393
394
D. BROTHWELL
AND
R. BURLEIGH
(1) Ser. I. 83. 4434. Californian Amerindian of Late Horizon date (i.e. within the range c. 300-1500 AD) Berkeley collection. Possible evidence of treponemal infection associated directly with this specimen. (2) May’s Lick, Kentucky. 20/915. “Prehistoric” Amerindian. A.M.N.H. collection, New York. At least nine individuals displayed vault changes which might indicate treponematoses. (3) Horr’s Island, Florida. Parts of two Amerindian skeletons: 352156 and 352162. Smithsonian collection, Washington. “Late prehistoric”. A number of specimens (but not these) in the collection displayed osteitic changes which could be of treponemal origin. (4) Cco. 138. 6091. Californian Amerindian of Late Horizon date. Berkeley collection. This specimen provides further direct skeletal dating evidence for Late Horizon people. In terms of pathology, this individual displays evidence of spinal osteitis not indicative of a treponemal infection but probably of tuberculosis (another disease of controversial pre-Columbian antiquity). Further details of these specimens will be presented in a review article (by DRB) appear in a subsequent issue of this journal.
to
Results Five radiocarbon dates have been obtained by the British Museum laboratory for bones (femora) from the Amerindian skeletons listed above. The results of the radiocarbon measurements are given in Table 1. In line with the usual practice when dating bone, only the collagen content of these samples was used. Collagen is generally accepted to be the most reliable component of bone for radiocarbon dating, dates on whole ancient bone tending to be too young because the inorganic carbonates in the structure readily undergo exchange with atmospheric carbon dioxide or with bicarbonates in ground-water. As an organic substance collagen is not subject to such exchange processes and can be completely freed from the mineral constituents of bone by controlled soaking in dilute acid. The dates were obtained by liquid scintillation counting of benzene synthesized from the individual pure collagen samples, and have all been corrected for isotopic fractionation. The laboratory and computational methods used are fairly standard among radiocarbon dating laboratories and have been described in detail elsewhere (Burleigh et al., in press). Table 1. Radiocarbon and absolute dates for Amerindian human skeletal material showing evidence of special pathology
BM-no.
Sample
462
Californian Ser. I. 83. 4434 Californian Cco. 138. 6091 May’s Lick 201915 Horr’s Island 352156 Horr’s Island 352162
463 464 465 466
Radiocarbon date bp (1950)
Calendar date BP (1950) AD
Years before Columbian contact
857& 52
845+
65 1105
387
622& 63
625i
69
1325
167
563+104 735& 83
580+108 730& 92
1370 1220
122 272
852&120
845hl26
1105
387
TREPONEMATOSES
IN MAN
305
In Table 1 the dates given in radiocarbon years before present (bp) are based on the conventional 5570 year half-life for i4C. The associated error terms are derived from counting statistics alone and are equivalent to one standard deviation (I a). This is the usual mode of expression of “raw“ radiocarbon dates. Past variations in the level of natural 14C such that radiocarbon and calendar years are not necessarily directly equivalent are now well attested (see, for example, Olsson, 1970) but the differences are not large in the period in which these particular dates fall and can almost be disregarded here. However, in the interest of greater absolute accuracy, the estimated equivalent calendar dates (denoted BP/AD) are also given in the Table and these allow both for natural l4C variations, using the data of Damon et al. (1972) and the more accurate “new” half-life value for l4C (5730 years). As far as the measurements considered here are concerned the combined effect of these two corrections is small so that the final dates remain practically unchanged although it will be seen that the associated error terms are slightly increased, reflecting uncertainties in the calibration data. Closely similar results would be obtained by using other current radiocarbon calibration relationships (for example, the MASCA tables of Ralph ef al., 1973). From the results it can be concluded that all the dates obtained in this study would appear to be fairly certainly pre-Columbian with the possible exception of the May’s Lick sample (BM-464). Nevertheless, it should be noted that the estimated date for the May’s Lick sample is also some time before Columbian contact and only the relatively large error term of this measurement dictates the need for greater caution in its interpretation. It would obviously be desirable to add further samples to this series of measurements so as to provide enough values for a rigorous analysis to be made of their distribution in time. Conclusions
In an endeavour to clarify a little the pre-Columbian antiquity of treponematoses in the New World, human bone samples were submitted for radiocarbon analysis. Except for Cco. 138.6091, these specimens were in all cases from cemeteries which had produced bone pathology suggesting a treponemal disease. It was not possible in two cases (Horr’s Island samples) to date bone specifically from the pathological specimens, but it seems likely that there was reasonable contemporaneity with those tested. The radiocarbon results give strong support to the view that late pre-Columbian Amerindian communities in various parts of the U.S.A. at least were well acquainted with one or other bonemodifying treponemal infection. It might, of course, still be argued that contact with the Old World could have occurred some centuries earlier-to the extent of providing a corridor for the passage of such a disease type-but it must also be remembered that there is not certain osteological evidence of a treponemal disease in the European area prior to the sixteenth century. Moreover, the evidence from the radiocarbon dated material from Indian Knoll and Tehuacan seems to establish a very considerable antiquity for these micro-organisms in the New World, even if during these earlier phases the disease was restricted in extent. Acknowledgements
We wish to express our thanks to all those in the Lowie Museum of Anthropology at Berkeley, the Smithsonian Institution of Washington and the American Museum of Natural History in New York, who were in any way drawn into considering or despatching our specimen needs. We wish to express special thanks to Professor Robert Heizer, Dr J. Lawrence Angel, and Professor H. Shapiro who were initially approached for help.
D. BROTHWELL
AND R. BURLEIGH
The radiocarbon samples were kindly prepared and measured by Mr A. D. Hewson and Mr N. D. Meeks of the British Museum Research Laboratory. References Brothwell, D. R. (1970). The real history of syphilis. Science Journal 6, 27-32. Burleigh, R., Hewson,A. & Meeks, N. (1976). British Museumnatural radiocarbon measurements VIII. Radiocarbon 18 (1) (in press). Damon, P. E., Long, A. & Wallick, E. I. (1972).Dendrochronologiccalibration of the carbon-14time scale.In (T. A. Rafter & T. Grant-Taylor, Eds.), Proceedings of the 8th International Conference on Radiocarbon Dating. Wellington: Royal Society of New Zealand, Vol. 1, pp. A29-43. Goff, C. W. (1967).Syphilis. In (D. Brothwell & A. T. Sandison,Eds.), Diseases in Antiquity. Springfield: Thomas, pp. 279-294. Hackett, C. J. (1963).On the origin of the human treponematoses. Bulletin of the World Health Organization 29, 741. Henschen,F. (1966). The History of Diseases. Harlow: Longmans. Johnson,F. & MacNeish, R. (1972). Chronometric dating. In (F. Johnson,Ed.), The Prehistory of the Tehuucan Valley. 4. Chronology and Irrigation. Austin: University of Texas Press,pp. 3-55. Libby, W. F. (1952). Radiocarbon Dating. Chicago: Chicago University Press,p. 78. Olsson,I. U. (Ed.) (1970).Radiocarbon Vuriations and Absolute Chronology. New York: John Wiley. Ralph, E. K., Michael, H. N. & Han, M. C. (1973).Radiocarbon datesand reality. MASCA Newsletter 9 (l), l-20 (Philadelphia,University Museum). Snow, C. E. (1948).Indian Knoll skeletonsof Site OH2, University of Kentucky Reports in Anthropology IV, 377-554.