Trade patterns facilitating highly pathogenic avian influenza virus dissemination in the free-grazing layer duck system in Vietnam

Highly pathogenic avian influenza (HPAI) viruses continue to threaten smallholder poultry producers in several South‐east Asian countries, including Vietnam. In particular, the free‐grazing duck system has been repeatedly highlighted as a major risk factor for HPAI outbreaks. Free‐grazing ducks, which scavenge on rice paddies after the harvest, account for a large proportion of the duck population in Vietnam and the wider South‐east Asian region. However, the structure and dynamics of the free‐grazing duck production from farm to consumption has not been described for Vietnam. In this study, we used a value chain approach to provide a complete picture of the actors involved in the production and marketing of free‐grazing duck eggs and spent layer ducks, as well as to investigate the governance structure of this food system. Group interviews and key informant interviews were conducted in two provinces located in the Mekong River Delta (MRD) and the Red River Delta (RRD). The results presented here highlight similarities and differences in farming and trade practices between the two provinces. The trade of spent layer ducks involved large volumes of live ducks being sent to China and Cambodia for consumption, generating a substantial risk of transboundary spread of pathogens, including HPAI viruses. We describe the major role of “duck yards”, which act as hubs in the northbound trade of spent layer ducks. These yards should be considered as essential links in the value chain of spent layer ducks when considering HPAI surveillance and control. The veterinary authorities are only marginally involved in the value chain activities, and their influence could be strengthened by increasing surveillance activities for instance in duck yards. Last, we discuss the dynamics of the duck value chain and further implications for future HPAI management policies

Development of a Human Cytomegalovirus (HCMV)-Based Therapeutic Cancer Vaccine Uncovers a Previously Unsuspected Viral Block of MHC Class I Antigen Presentation

Human cytomegalovirus (HCMV) induces a uniquely high frequency of virus-specific effector/memory CD8+ T-cells, a phenomenon termed “memory inflation”. Thus, HCMV-based vaccines are particularly interesting in order to stimulate a sustained and strong cellular immune response against cancer. Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with high lethality and inevitable relapse. The current standard treatment does not significantly improve the desperate situation underlining the urgent need to develop novel approaches. Although HCMV is highly fastidious with regard to species and cell type, GBM cell lines are susceptible to HCMV. In order to generate HCMV-based therapeutic vaccine candidates, we deleted all HCMV-encoded proteins (immunoevasins) that interfere with MHC class I presentation. The aim being to use the viral vector as an adjuvant for presentation of endogenous tumor antigens, the presentation of high levels of vector-encoded neoantigens and finally the repurposing of bystander HCMV-specific CD8+ T cells to fight the tumor. As neoantigen, we exemplarily used the E6 and E7 proteins of human papillomavirus type 16 (HPV-16) as a non-transforming fusion protein (E6/E7) that covers all relevant antigenic peptides. Surprisingly, GBM cells infected with E6/E7-expressing HCMV-vectors failed to stimulate E6-specific T cells despite high level expression of E6/E7 protein. Further experiments revealed that MHC class I presentation of E6/E7 is impaired by the HCMV-vector although it lacks all known immunoevasins. We also generated HCMV-based vectors that express E6-derived peptide fused to HCMV proteins. GBM cells infected with these vectors efficiently stimulated E6-specific T cells. Thus, fusion of antigenic sequences to HCMV proteins is required for efficient presentation via MHC class I molecules during infection. Taken together, these results provide the preclinical basis for development of HCMV-based vaccines and also reveal a novel HCMV-encoded block of MHC class I presentation

The Lore of Low Methane Livestock:Co-Producing Technology and Animals for Reduced Climate Change Impact

Methane emissions from sheep and cattle production have gained increasing profile in the context of climate change. Policy and scientific research communities have suggested a number of technological approaches to mitigate these emissions. This paper uses the concept of co-production as an analytical framework to understand farmers’ evaluation of a 'good animal’. It examines how technology and sheep and beef cattle are co-produced in the context of concerns about the climate change impact of methane. Drawing on 42 semi-structured interviews, this paper demonstrates that methane emissions are viewed as a natural and integral part of sheep and beef cattle by farmers, rather than as a pollutant. Sheep and beef cattle farmers in the UK are found to be an extremely heterogeneous group that need to be understood in their specific social, environmental and consumer contexts. Some are more amenable to appropriating methane reducing measures than others, but largely because animals are already co-constructed from the natural and the technical for reasons of increased production efficiency

2011 Conference of the Ecological Society of Australia (ESA 2011)

Understanding native ecosystem responses to altered and novel disturbances is a crucial foundation for policy development and management aimed at maintaining and enhancing biodiversity and ecosystem services in production landscapes. Remnant riparian woodland ecosystems in an intensively-farmed landscape in the northern Murray-Darling Basin are subject to significant changes in hydrological regimes and land use intensity, and exhibit dieback and limited recruitment of the dominant canopy species complex, Eucalyptus camaldulensis/tereticornis, widespread invasion by the introduced perennial herb Phyla canescens, and altered floristic composition and function. Current land and water management fails to address critical changes in this landscape, and hence curb ongoing degradation. This study indicates the importance of systems-based empirical research to developing better understanding of the dynamics of remnant ecosystems in highly-modified landscapes. It uses a resilience-based state and transition modelling approach to synthesise results, highlighting key drivers of stability and critical change in the condition and function of these riparian ecosystems. Such research is vital to understanding the ecology of remnant native ecosystems and their role in the provision of important ecosystem services in production landscapes. Representation of this understanding in a simple conceptual model provides an important link to support evidence-based policy and adaptive management

2004 Conference of the Ecological Society of Australia (ESA 2004)

Recent vegetation management legislation in Queensland protects the extent of native woody vegetation types, but does little to ensure that fundamental ecological values will be retained within remnants. Those remnants embedded in landscapes that have undergone major land use change are particularly at risk. This project aims to look at (i) the role of major landscape change on the health and function of Eucalyptus camaldulensis/tereticornis riparian woodland communities occurring on the Darling Downs, an intensive cropping area in southern Queensland, and (ii) the potential for restoration of these ecosystems through moves to re-establish 'environmental flows' and control ecologically-significant weed species. The study will take a multi-dimensional approach including time-series landscape analysis (GIS-based), field assessment of current community composition and condition, experimental investigation of interactions between lippia (Phyla canescens) and Eucalyptus species involving both competition for moisture and chemical (allelopathic) suppression, and an investigation of landholder responses to eucalypt dieback and lippia infestation

2010 Conference of the Ecological Society of Australia (ESA 2010)

Altered hydrological regimes are significant drivers of ecosystem change in riverine, riparian and floodplain ecosystems. This study has found that declining condition in Eucalyptus camaldulensis/E. tereticornis riparian woodlands of the highly-modified Upper Condamine floodplain, southern Queensland, is predominantly linked to falling groundwater levels associated with extraction for irrigation. Evidence of dieback in this species complex increases with groundwater depth falling below 13-16m, and community composition (functional group diversity) is strongly associated with both groundwater depth and tree condition. These findings contrast with studies in Murray River floodplain woodlands where poor tree health is associated with soil salinisation associated with rising water tables and/or altered flood regimes. Results from this study are summarized in a semi-quantitative State-and-Transition resilience model, identifying critical thresholds for the persistence of this essentially groundwater-dependent ecosystem. Such systems, currently existing close to ecological thresholds, contribute significantly to our understanding of how ecological systems respond to change, and of how major disturbances such as climate change may play out across landscapes

2014 Conference of the Ecological Society of Australia (ESA 2014)

Lippia (Phyla canescens), a significant invasive weed, is a recognized threat to floodplain woodlands in Australia, particularly in the Murray-Darling Basin. Current control methods include the use of herbicides, which can be costly and environmentally harmful, particularly in riparian areas. 'Environmentally friendly' control mechanisms are yet to be found, with the potential for biological control still being researched. This research explores the use of fire as a potential control method to help slow the expansion and growth of lippia. Lippia response to fire and the effect of fire in lippia-invaded landscapes has not previously been investigated. Half of the St. Ruth Reserve south of Dalby in Southern Queensland was subject to a control burn in November 2013 by the Western Downs Regional Council in an attempt to reduce lippia abundance in this remnant riparian woodland. This research investigates the response of lippia to the burn. The study will compare the cover abundance of lippia and major functional plant groups between burnt and unburnt (control) sites within the reserve; it will also investigate the impact of fire on lippia germination rates in soil samples from burnt and unburnt sites. Additional studies testing lippia seed viability, using tetrazolium staining, will also be conducted after a range of fire mimicking treatments have been applied to seeds and compared to controls from an unburnt area. This research will contribute to evidence-based decision-making for improved management of lippia-invaded remnant ecosystems

Chronic groundwater decline: a multi-decadal analysis of groundwater trends under extreme climate cycles

Chronic groundwater decline is a concern in many of the world’s major agricultural areas. However, a general lack of accurate long-term in situ measurement of groundwater depth and analysis of trends prevents understanding of the dynamics of these systems at landscape scales. This is particularly worrying in the context of future climate uncertainties. This study examines long‐term groundwater responses to climate variability in a major agricultural production landscape in southern Queensland, Australia. Based on records for 381 groundwater bores, we used a modified Mann-Kendall non-parametric test and Sen’s slope estimator to determine groundwater trends across a 26-year period (1989–2015) and in distinct wet and dry climatic phases. Comparison of trends between climatic phases showed groundwater level recovery during wet phases was insufficient to offset the decline in groundwater level from the previous dry phase. Across the entire 26-year sampling period, groundwater bore levels (all bores) showed an overall significant declining trend (p0.05). Spatially, both declining and rising bores were highly clustered. We conclude that over 1989–2015 there is a significant net decline in groundwater levels driven by a smaller subset of highly responsive bores in high irrigation areas within the catchment. Despite a number of targeted policy interventions, chronic groundwater decline remains evident in the catchment. We argue that this is likely to continue and to occur more widely under potential climate change and that policy makers, groundwater users and managers need to engage in planning to ensure the sustainability of this vital resource

11th International Riversymposium: A Future of Extremes

The Condamine River, at the headwaters of the Murray-Darling basin, drains one of the most intensively-farmed landscapes in eastern Australia. Riparian woodland remnants on the floodplain sections of the upper Condamine are widely recognised as being in generally poor condition, with evidence of significant dieback and limited recruitment of canopy species, as well as widespread invasion by the introduced perennial herb Phyla canescens (lippia). These communities, in keeping with most remnant ecosystems of agricultural landscapes, are poorly understood in terms of their diversity, function and dynamics (resilience) under altered disturbance regimes. This research investigates the condition (health and function) of Eucalyptus tereticornis/camaldulensis riparian woodland communities of the Condamine floodplain in relation to selected natural and anthropogenic disturbance factors (e.g. climate variability, changes in land- and wateruse, weed invasion) operating at a range of spatial and temporal scales. The study takes a multi-dimensional approach aimed at developing an integrated understanding of key drivers and mechanisms of ecosystem change in these environments. It also investigates the potential of simple conceptual tools (e.g. State-and-Transition and Bayesian Belief Network approaches) to model system dynamics and predict outcomes of future climate and land and water management scenarios, including environmental flow restoration