Coupled Natural-Human Systems and Emerging Infectious Diseases: Anthropogenic environmental change and avian influenza in Vietnam

As part of the coupled natural-human (CNH) system, humans are exposed to infectious diseases from each other and other animals. Previous research suggests that disease outbreaks are associated with environmental changes such as urbanization, agricultural change, and natural habitat alterations that occur as societies evolve. However, the mechanisms underlying disease outbreaks are not well understood because the interactions within and among CNH systems are complex. Studying the role of societal development in disease transmission is urgent and critical for improving the prediction and control of disease. The project will examine how the outbreak of highly pathogenic avian influenza (HPAI), as measured by numbers of diseased poultry in Vietnam, varies across traditional settings (customary agricultural practices and housing), modern settings (agricultural modernization and industrial cities), and transitional settings (chaos of in-between). The project will also examine whether perceptions of HPAI risk can be associated with societal transitions. Conducting the project in Vietnam using a 'lived' place-based unit of analysis is a novel way of looking at disease transmission because it suggests that these risks are not an accident of time and place, but rather are the product of the modernization transition. Vietnam is an excellent setting for this research because it is the world’s second-fastest growing economy and is consequently experiencing rapid environmental transformations. Three major waves of HPAI have occurred in Vietnam, resulting in 45 million bird deaths between December 2003 and August 2005. This country has also reported 106 confirmed human cases with 52 deaths. The objectives of this research are to: (1) test a model of relationships between human-caused environmental transformations such as urbanization, agricultural change, and natural habitat alteration and the emergence and reemergence of infectious diseases in Vietnam; (2) examine the influence of socio-ecological and socio-psychological variables on individuals’ perceptions of and responses to the risk of HPAI in traditional, transitional, and modern communes; (3) integrate the research with education and training programs at the University of Hawaii, the East-West Center, and the Hanoi University of Agriculture in Vietnam; (4) establish new collaboration among scientists from multiple disciplines and institutions and among U.S. academic institutions, industry, government, and international partners from countries in the Asia-Pacific region. Because complexity is scale sensitive the project will collect and analyze data at national, commune, and household scales. The methods to be used include field observations, face-to-face interviews, geographical information systems, remote sensing, global positioning systems, and statistical tools. An a priori specific structural equation model will be tested utilizing data on national-level variables previously shown to be correlated with poultry deaths caused by HPAI. At the commune and household scales the team will conduct quantitative analyses using a type of multiple regression called multilevel modeling. The project has significant theoretical, methodological, and practical implications. Developing basic principles and methods for understanding the complex interactions within and among natural and human systems at multiple spatial scales will help to elucidate the mechanisms underlying the emergence of new and reemerging infectious diseases. Integrating interdisciplinary methods and advanced technologies will provide new methods for investigating the complex and interacting relationships in coupled natural and human systems. The outputs will enhance the capabilities of researchers, practitioners, and policy makers at local, national, and regional levels. The work will provide useful insights for designing policies for preventing and managing infectious disease outbreaks in Vietnam and other developing nations. The findings will be of general interest because of the rapid development and increasingly complicated natural-human interactions worldwide.