Doctoral student Carolyn Orbann (University of Missouri), under the guidance of Dr. Lisa Sattenspiel, will investigate the effects of traditional kinship structures on disease-related morbidity and mortality in a population of nineteenth century indigenous Californians at Mission Basilica San Diego de Alcala. Research will focus on assessing the stability of traditional kin structures within the mission and testing whether individuals with more kin at the mission experienced different risks of infection and/or death during acute infectious disease epidemics than did individuals with fewer kin. Research questions will be addressed through family and lineage reconstruction and development and analysis of an agent-based computer simulation model. Family and lineage reconstruction will be accomplished using vital records from Mission San Diego sacramental registers and historical and ethnographic information. The model to be used in this study takes into account daily activities, social contacts and age- and sex-structured behaviors. The model population is based on Mission vital statistics data; model parameters are based on available historical, ethnographic, and epidemiological information. Model results will be compared with documented mortality patterns to shed light on the possible cause of an observed mortality spike in the early 1800s.
This study will result in an in-depth understanding of the impact of missionization on an understudied population (the Kumeyaay) and will contribute to the wider base of knowledge on the consequences of European colonization of North America. While the cultural attributes of the Kumeyaay have been studied previously, there have been few attempts to understand the direct impact of introduced disease as a cause of population decline. This study also provides greater knowledge of the roots of contemporary Kumeyaay and Latino populations in Southern California. In addition, the model developed in this project can be adapted for use in the study of disease in other kin-based populations with limited access to Western medicine. Funding this research also supports the education of a graduate student.
There are four broad goals associated with this project: Identify disease-related mortality among the Kumeyaay population at Mission San Diego using available historic data. Reconstruct the population using mission records and evaluate the structure of the population for consistency with ethnographically recorded kinship rules. Develop a computer simulation model of an acute, infectious disease in the indigenous population living at Mission San Diego. Test hypotheses about the effects of a possible measles epidemic in the mission population during the winter of 1805-1806. These goals were addressed in the following manner: Digitized mission records (baptismal, marriage, and burial records) were analyzed to identify family structure and mortality patterns at the mission. Primary and secondary historical data were reviewed in order to contextualize knowledge about life at the mission. The 1805 population was reconstructed for use as a reference population during the model-building stage of the project. The general population structure (size, number of males and females) was checked against available primary source data. Census data were not available for this population, so household reconstruction could not be completed for the historical population. A computer simulation model was completed that used the 1805 Mission San Diego population as a reference population. Households for the model population were inferred based on ethnographic and historical data and missing data were added using statistical techniques. The model was run and epidemic data were generated. The model was initially set up to model a measles epidemic in a population without prior mealses immunity. Several early findings are available. Initial results indicate that the model currently overestimates the mortality during a measles epidemic in this population. There are several possible interpretations at this point. The first is that the spike in deaths seen in the historical record at this time does not reflect an measles epidemic, but some other disease or a combination of mortality causes. The second, more likely, interpretation is that the population at the mission does have prior experience with the measles. Thus, part of the population would have immunity and would not have been infected during an epidemic. This could be tested with the model by changing some attributes of the model population to include immunity in some individuals. This will take place at a later stage in the project. Model data indicate an extremely high likelihood of a large epidemic of infectious disease in this community, once the disease is introduced. This means that living conditions at the mission were such that the spread of disease was highly likely, no matter what the disease was. Though risk of infection differed somewhat by sex and age, all individuals would have been at extreme risk for exposure if a novel disease were to enter the community. This is due to population density in the community and regular congregation of the population for community events, like church services. This project benefits the general public, especially contemporary Native Californian communities, those involved in public education in California (study of mission life forms a part of the curriculum in elementary school), and anyone interested in the history of California or the Catholic Church in North America by providing additional detail and analysis of population dynamics at Mission San Diego. Much of what is known about Native Californians' experiences of mission life comes from studies at other missions. Additionally, the development and application of the computer simulation model to this historic context is a novel use of this technology. These techniques and the model itself could be of use to researchers in a wide variety of fields who are interested in studying disease in non-western, rural or indigenous populations with limited access to contemporary healthcare.