Bruce A. Wilcox

Metagenomic shotgun sequencing of a Bunyavirus in wild-caught Aedes aegypti from Thailand informs the evolutionary and genomic history of the Phleboviruses.

Arthropod-borne viruses significantly impact human health. They span multiple families, all of which include viruses not known to cause disease. Characterizing these representatives could provide insights into the origins of their disease-causing counterparts. Field-caught Aedes aegypti mosquitoes from Nakhon Nayok, Thailand, underwent metagenomic shotgun sequencing to reveal a Bunyavirus closely related to Phasi Charoen (PhaV) virus, isolated in 2009 from Ae. aegypti near Bangkok. Phylogenetic analysis of this virus suggests it is basal to the Phlebovirus genus thus making it ideally positioned phylogenetically for understanding the evolution of these clinically important viruses. Genomic analysis finds that a gene necessary for virulence in vertebrates, but not essential for viral replication in arthropods, is missing. The sequencing of this phylogenetically-notable and genomically-unique Phlebovirus from wild mosquitoes exemplifies the utility and efficacy of metagenomic shotgun sequencing for virus characterization in arthropod vectors of human diseases.

The role of evolutionary biology in research and control of liver flukes in Southeast Asia

Stimulated largely by the availability of new technology, biomedical research at the molecular-level and chemical-based control approaches arguably dominate the field of infectious diseases. Along with this, the proximate view of disease etiology predominates to the exclusion of the ultimate, evolutionary biology-based, causation perspective. Yet, historically and up to today, research in evolutionary biology has provided much of the foundation for understanding the mechanisms underlying disease transmission dynamics, virulence, and the design of effective integrated control strategies. Here we review the state of knowledge regarding the biology of Asian liver Fluke-host relationship, parasitology, phylodynamics, drug-based interventions and liver Fluke-related cancer etiology from an evolutionary biology perspective. We consider how evolutionary principles, mechanisms and research methods could help refine our understanding of clinical disease associated with infection by Liver Flukes as well as their transmission dynamics. We identify a series of questions for an evolutionary biology research agenda for the liver Fluke that should contribute to an increased understanding of liver Fluke-associated diseases. Finally, we describe an integrative evolutionary medicine approach to liver Fluke prevention and control highlighting the need to better contextualize interventions within a broader human health and sustainable development framework.

Untangling the Complexity of Liver Fluke Infection and Cholangiocarcinoma in NE Thailand Through Transdisciplinary Learning

AbstractThis study demonstrates how a transdisciplinary learning approach provided new insights for explaining persistent Opisthorchis viverrini infection in northern Thailand, as well as elucidating problems of focusing solely on the parasite as a means of addressing high prevalence of cholangiocarcinoma. Researchers from diverse backgrounds collaborated to design an investigative homestay program for 72 Singaporean and Thai university students in five northeast Thai villages. The students explored how liver fluke infection and potential cholangiocarcinoma development are influenced by local landscape dynamics, aquatic ecology, livelihoods, food culture and health education. Qualitative fieldwork was guided daily by the researchers in a collaborative, co-learning process that led to viewing this health issue as a complex system, influenced by interlinked multidimensional factors. Our transdisciplinary experience has led us to believe that an incomplete understanding of these linkages may reduce the efficacy of interventions. Further, viewing liver fluke infection and cholangiocarcinoma as the same issue is inadvisable. Although O. viverrini infection is an established risk factor for the development of cholangiocarcinoma, multiple factors are known to influence the likelihood of acquiring either. Understanding the importance of the current livelihood transition, landscape modification and the resulting mismatch between local cultures and new socio-ecological settings on cholangiocarcinoma initiation and liver fluke transmission is of critical importance as it may help readjust our view of the respective role of O. viverrini and other socioeconomic risk factors in cholangiocarcinoma etiology and refine intervention strategies. As demonstrated in this study, transdisciplinary approaches have the potential to yield more nuanced perspectives to complex diseases than research that focuses on specific aspects of their epidemiology. They may therefore be valuable when designing effective solutions to context-sensitive diseases such as liver fluke infection and cholangiocarcinoma.

Intensified food production and correlated risks to human health in the Greater Mekong Subregion: a systematic review

BackgroundIntensified food production, i.e. agricultural intensification and industrialized livestock operations may have adverse effects on human health and promote disease emergence via numerous mechanisms resulting in either direct impacts on humans or indirect impacts related to animal and environmental health. For example, while biodiversity is intentionally decreased in intensive food production systems, the consequential decrease in resilience in these systems may in turn bear increased health risks. However, quantifying these risks remains challenging, even if individual intensification measures are examined separately. Yet, this is an urgent task, especially in rapidly developing areas of the world with few regulations on intensification measures, such as in the Greater Mekong Subregion (GMS).MethodsWe systematically searched the databases PubMed and Scopus for recent studies conducted on the association between agricultural (irrigation, fertilization, pesticide application) and livestock (feed additives, animal crowding) intensification measures and human health risks in the GMS. The search terms used were iteratively modified to maximize the number of retrieved studies with relevant quantitative data.ResultsWe found that alarmingly little research has been done in this regard, considering the level of environmental contamination with pesticides, livestock infection with antibiotic resistant pathogens and disease vector proliferation in irrigated agroecosystems reported in the retrieved studies. In addition, each of the studies identified focused on specific aspects of intensified food production and there have been no efforts to consolidate the health risks from the simultaneous exposures to the range of hazardous chemicals utilized.ConclusionsWhile some of the studies identified already reported environmental contamination bearing considerable health risks for local people, at the current state of research the actual consolidated risk from regional intensification measures cannot be estimated. Efforts in this area of research need to be rapidly and considerably scaled up, keeping pace with the current level of regional intensification and the speed of pesticide and drug distribution to facilitate the development of agriculture related policies for regional health promotion.

Mosquito vector-associated microbiota: Metabarcoding bacteria and eukaryotic symbionts across habitat types in Thailand endemic for dengue and other arthropod-borne diseases

Abstract Vector‐borne diseases are a major health burden, yet factors affecting their spread are only partially understood. For example, microbial symbionts can impact mosquito reproduction, survival, and vectorial capacity, and hence affect disease transmission. Nonetheless, current knowledge of mosquito‐associated microbial communities is limited. To characterize the bacterial and eukaryotic microbial communities of multiple vector species collected from different habitat types in disease endemic areas, we employed next‐generation 454 pyrosequencing of 16S and 18S rRNA amplicon libraries, also known as metabarcoding. We investigated pooled whole adult mosquitoes of three medically important vectors, Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus, collected from different habitats across central Thailand where we previously characterized mosquito diversity. Our results indicate that diversity within the mosquito microbiota is low, with the majority of microbes assigned to one or a few taxa. Two of the most common eukaryotic and bacterial genera recovered (Ascogregarina and Wolbachia, respectively) are known mosquito endosymbionts with potentially parasitic and long evolutionary relationships with their hosts. Patterns of microbial composition and diversity appeared to differ by both vector species and habitat for a given species, although high variability between samples suggests a strong stochastic element to microbiota assembly. In general, our findings suggest that multiple factors, such as habitat condition and mosquito species identity, may influence overall microbial community composition, and thus provide a basis for further investigations into the interactions between vectors, their microbial communities, and human‐impacted landscapes that may ultimately affect vector‐borne disease risk.

Toward Operational Criteria for Ecosystem Approaches to Health

Center for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536 Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland Centre for Public Health and Ecosystem Research (CENPHER) and International Livestock Research Institute (ILRI), Hanoi School of Public Health (HPPH), Hanoi, Vietnam World Agroforestry Centre (ICRAF), East and Central Asia Region, 132# Lanhei Road, Heilongtan, Kunming 650201, Yunnan, China Global Health Asia, Integrative Education and Research Programme, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand

News from the IAEH.

The context-dependent nature of infectious disease outcomes advocates considering ecological determinants and hence, when the host is human, the incorporation of human ecology, a social science. The importance of integrating social considerations into ecological studies of infectious diseases is essential for research on sustainable disease control. Taking into account the complex interactions from genes to communities across spatial and temporal scales is a fundamental necessity; however, practical implementation remains limited because transdisciplinary research that integrates knowledge from different unrelated disciplines (e.g. social science and ecology) and non-academic knowledge sources is rarely achieved. Increasingly, graduate programs acknowledge the need for integrative investigations of infectious diseases. Many emphasize the multidisciplinary nature of their curriculum where clinical, population, laboratory, and social sciences can be integrated. Yet despite these good intentions, the Ecohealth agenda is impeded by conceptual compartmentalization and the limited dialog among social, natural, biomedical, and public health sciences personnel. The lack of a cohesive conceptual framework that links disciplinespecific processes is often at the origin of this limitation. To rectify this historic trend and restore scholarly breadth of original university science, future or evolving graduate programs should consider incorporating in their curriculum a certain number of mandatory courses such as philosophy and history of science or ethics in science. Additionally, graduate programs may want to organize advanced workshops focusing on the concept of multiple working hypotheses and how to implement multi-scale causal inference in disease research. With a deepened philosophical background, students in health sciences should be able to establish solid foundations for critical thinking and intellectual openness and become the scientific leaders that will reconcile holistic and reductionist approaches in health sciences. Transdisciplinarity and the proper incorporation of social determinants also implies that institutions and individuals become immersed in the local culture for more than their sampling season, especially when research is conducted abroad. Researchers should also aim to involve themselves in the daily life of local communities, enabling individuals to better understand social networks and how they impact disease outcomes. Investigators should also be open to ‘‘intellectual out-breeding’’ and receptive to local wisdom. Finally, although pressure to publish is strong, researchers must not forget the true finality of their work: helping the community. These elements are rarely taught or even suggested in graduate programs because they are emerging ethical values often contingent on one’s life experience and exposure to real situations. Yet this ethical perspective is critical to better understand the socio-ecological determinants of disease dynamics. In practice, the support and organization of educational interventions describing the research-to-practice-to-community continuum (targeting both researchers and local stakeholders) are critical to make ethical principles operational. I recently took a post-doctoral position with the Tropical Disease Research Laboratory (TDR), a unit associated with the Faculty of Medicine, Khon Kaen University (KKU) in northeastern Thailand. The research focus of TDR is on Opistorchis viverrini (OV), a liver fluke that Correspondence to: Pierre Echaubard, e-mail: pn_echaubard@laurentian.ca EcoHealth 12, 4–7, 2015 DOI: 10.1007/s10393-014-0999-7