Severe acute respiratory syndrome coronavirus (SARS-CoV) moved into humans from a reservoir species and subsequently caused an epidemic in its new host. We know little about the processes that allowed the cross-species transfer of this previously unknown virus. I discuss what we have learned about the movement of viruses into humans from studies of influenza A, both how it crossed from birds to humans and how it subsequently evolved within the human population. Starting with a brief review of severe acute respiratory syndrome to highlight the kinds of problems we face in learning about this viral disease, I then turn to influenza A, focusing on three topics. First, I present a reanalysis of data used to test the hypothesis that swine served as a 'mixing vessel' or intermediate host in the transmission of avian influenza to humans during the 1918 'Spanish flu' pandemic. Second, I review studies of archived viruses from the three recent influenza pandemics. Third, I discuss current limitations in using molecular data to study the evolution of infectious disease. Although influenza A and SARS-CoV differ in many ways, our knowledge of influenza A may provide important clues about what limits or favours cross-species transfers and subsequent epidemics of newly emerging pathogens.

Background

Results

Conclusion

A single measles vaccination provides lifelong protection. No antigenic variants that escape immunity have been observed. By contrast, influenza continually evolves new antigenic variants, and the vaccine has to be updated frequently with new strains. Both measles and influenza are RNA viruses with high mutation rates, so the mutation rate alone cannot explain the differences in antigenic variability.

We develop a new hypothesis to explain antigenic stasis versus change. We first note that the antigenically static viruses tend to have high reproductive rates and to concentrate infection in children, whereas antigenically variable viruses such as influenza tend to spread more widely across age classes. We argue that, for pathogens in a naive host population that spread more rapidly in younger individuals than in older individuals, natural selection weights more heavily a rise in reproductive rate. By contrast, pathogens that spread more readily among older individuals gain more by antigenic escape, so natural selection weights more heavily antigenic mutability.

These divergent selective pressures on reproductive rate and antigenic mutability may explain some of the observed differences between pathogens in age-class bias, reproductive rate, and antigenic variation.

This study is about the migration of young men from the town of Oxkutzcab in the Yucatan peninsula of Mexico who against historical and contemporary structural conditions (Maya versus nation-state, globalizing of local economy, world system and free trade agreements) have chosen international migration as a strategy for survival and success. The purpose of this research is to illustrate the fundamental role of circular migration to and from San Francisco, California and Oxkutzcab, Yucatan, and dependence on transnational social ties. Field work was conducted in San Francisco, California, in 2004, followed by field work in Oxkutzcab, Yucatan, in 2005. Historically, migration within the state of Yucatan is not new. A brief historical background underlines the point that interstate migration as a result of wars, and later economic restructuring, can be regarded as a step-side to international migration. In addition, this work examines migration theory to understand the dynamics of contemporary international migration.

The purpose of this dissertation is to examine three primary research threads: to reclaim an invisible or lost history, to explore reasons why that history remains invisible or lost, and to examine the processes whereby individual and collective memories are remembered, forgotten, recollected, or discarded in the process of understanding the past, the present, and the future. Towards that end, this dissertation examines the past and present in relation to almost two dozen rural historically African American settlements throughout the San Joaquin Valley. In addition to capturing a lost and forgotten history, contemporary issues, including water and poverty, are addressed. As this dissertation captures much of this invisible history, it also looks at the impact of that history, the impact of reclaiming that history, and how an historical absence or presence impacts individual and collective identity. After an extensive literature review of theory relating to practice, habitus, power, and identity, several chapters are dedicated to laying out the lost history of these communities. These chapters are followed by chapters that examine the contemporary lives of the people who continue to live in these communities. This blend of historical and ethnographic research provides a picture of the past, the present, and (in some cases) a vision for the future.

My dissertation situates issues of urban space, place and renewal within a larger context of historical social memory.An open urban space that celebrated its 50th anniversary in 2014, the once-beautiful urban Fulton Mall in Fresno, CA served as abandoned parkland contested by city leaders and community members alike until a controversial infrastructure project began in 2016. I developed an ethnographic project of the site and the dynamics of local narrative. My research agenda concerns several key questions: How does social memory influence the construction of identity and citizenship at the local political level? How does the revitalization of open urban space play into this construction as the mechanism of a changing sense of citizenship? This small local contest about space is theoretically significant to the broader urban anthropology discipline, and was investigated ethnographically to best capture this particular contestation as historically and culturally-situated.The Fulton Mall’s revitalization serves as a test case for issues of space and community all urban centers will eventually confront,and are important to the master narratives of placemaking.Redevelopment construction on the mall happened during my fieldwork(2015-2017) and added a component of urgency to my research while also affording me the opportunity to see continuing citizen action unfold. My ethnographic evidence suggests that the political discussion engendered by the proposed changes and current revitalization of the Fulton Mall in Fresno is really a contestation of identity, in which the social memory of a community is highlighted and positioned in direct contest to the larger forces of a postmodern movement to manufacture space first, community second. My research highlights the focus on fiscal matters driving local planning projects as they relate to economic markets and city boosterism, not community desires, needs or history.