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1. Does Unplanned Urbanization Pose a Disease Risk in Asia? The Case of Avian Influenza in Vietnam

Author:
Sumeet Saksena
Publication Date:
01-2017
Content Type:
Special Report
Institution:
East-West Center
Abstract:
Cities are expanding very rapidly in Asia, often without adequate housing, transportation, water, or sanitation. ese new “peri-urban” areas may be hot spots for disease, both in humans and domestic animals. Research into the possible link between unplanned urban expansion and disease outbreaks compared patterns of land-use change with two major outbreaks in Vietnam of highly pathogenic avian in uenza (HPAI, subtype H5N1) that killed millions of chickens between 2003 and 2005. Work began by classifying communes into land-use categories: rural, peri-urban, urban, and urban core. e study found that peri-urban communes had at least a 150 percent higher risk of experiencing an H5N1 outbreak than did other types of commune, and that urbanization entails a spatial convergence of several key risk factors for H5N1 transmission. By focusing prevention programs on communes with these factors, the Vietnamese government can potentially improve disease prevention at lower cost. is research may also help explain the epidemi- ology of other infectious diseases, both in humans and livestock.
Topic:
Health, Urbanization, and International Development
Political Geography:
Asia

2. Perceived Risk of Avian Influenza in Poultry Varies with Urbanization in Vietnam

Author:
Jefferson Fox, Melissa L. Finucane, Sumeet Saksena, Nghiem Tuyen, James H. Spencer, Nguyen Lam, Trinh Dinh Thau, Tran Duc Vien, and Nancy D. Lewis
Publication Date:
10-2014
Content Type:
Working Paper
Institution:
East-West Center
Abstract:
Highly pathogenic avian influenza (HPAI) is an important public health concern because of its potential to cause widespread morbidity and mortality in humans and poultry and associated devastating economic losses. In this study we examined how perceptions of and response to the risk of HPAI in poultry vary across communes/wards in the north of Vietnam at different levels of urbanization (rural, transitional, urban). We conducted a quantitative household survey with 1073 respondents. Results suggested that the perceived risk of HPAI in poultry was highest in transitional and rural settings. Respondents in these settings were more likely than respondents in urban settings to agree that the process of change (in urbanization, agricultural practices, or natural habitat) increased the likelihood of an outbreak of HPAI in poultry. Compared with others, respondents in transitional areas reported that they do less planning and perceive vaccines to be more effective, while respondents in rural areas reported less perceived ability to separate infected poultry from others. We also found that the inability to respond is not necessarily because of an inability to perceive change but because, rapid and extensive change poses different challenges for poultry management as communes move from rural to transitional to urban settings. Our results suggest that public and animal health campaigns could be tailored in a way that recognizes the needs of poultry raisers in different settings.
Topic:
Health, Infectious Diseases, and Urbanization
Political Geography:
Asia and Vietnam

3. Role of Urbanization, Land-Use Diversity, and Livestock Intensification in Zoonotic Emerging Infectious Diseases

Author:
Jefferson Fox, Duong Nong, Miguel Castrence, James Spencer, Sumeet Saksena, Nguyen Lam, Tran Duc Vien, Michael Epprecht, Chinh Tran, Melissa Finucane, and Bruce Wilco
Publication Date:
10-2014
Content Type:
Working Paper
Institution:
East-West Center
Abstract:
Emerging infectious diseases (EIDs) continue to significantly threaten human and animal health. While there has been some progress in identifying underlying proximal driving forces and causal mechanisms of disease emergence, the role of distal factors is most poorly understood. This article focuses on analyzing the statistical association between highly pathogenic avian influenza (HPAI) H5N1 and urbanization, land-use diversity and poultry intensification. A special form of the urban transition—peri-urbanization—was hypothesized as being associated with 'hot-spots' of disease emergence. Novel metrics were used to characterize these distal risk factors. Our models, which combined these newly proposed risk factors with previously known natural and human risk factors, had a far higher predictive performance compared to published models for the first two epidemiological waves in Viet Nam. We found that when relevant risk factors are taken into account, urbanization is generally not a significant independent risk factor. However, urbanization spatially combines other risk factors leading to peri-urban places being the most likely 'hot-spots'. The work highlights that peri-urban areas have highest levels of chicken density, duck and geese flock size diversity, fraction of land under rice, fraction of land under aquaculture compared to rural and urban areas. Land-use diversity, which has previously never been studied in the context of HPAI H5N1, was found to be a significant risk factor. Places where intensive and extensive forms of poultry production are collocated were found to be at greater risk
Topic:
Health, Infectious Diseases, and Urbanization
Political Geography:
United States and Asia