Canine echinococcosis in Kyrgyzstan : detection, diagnosis, and dynamics

Human echinococcosis is an increasing public health issue in Kyrgyzstan, where Echinococcus granulosus and Echinococcus multilocularis are coendemic and domestic dogs are considered the primary source of human infection. A control scheme based upon dosing dogs with praziquantel was commenced in Kyrgyzstan in 2012 and was evaluated using ELISA tests to measure levels of Echinococcus-specific ‘coproantigens’ in canine faeces. The current study describes methods of interpretation of coproELISA test results, both prior to and during a control scheme, using data collected from dogs in southern Kyrgyzstan over a period of three years.Current methods of coproELISA test interpretation based upon selection of a single cut-off value are described and found to have considerable limitations. To address this, Bayesian mixture modelling was used to transform raw coproantigen data into a metric which approximates the possible worm burden in individual dogs and reduces test misclassification at the population level. This approach was validated using data from a panel of faecal samples of known status and was applied to data from samples of unknown status collected from Kyrgyz dogs. Multiple correspondence analysis was used to characterise the Kyrgyz study sites and identify possible associations with canine infection status (incorporating both coproELISA and coproPCR results), but did not identify any strong relationships. A mixed effects logistic regression modelling approach combined with model averaging was used to identify temporal and seasonal trends in coproantigen and coproPCR prevalence. A trend of decreasing test prevalence over time with pronounced seasonality was found for some test results. Finally, a mathematical model of transmission of both Echinococcus granulosus and Echinococcus multilocularis in Kyrgyzstan was developed and used to simulate the effects of a number of different dog dosing strategies. Canine echinococcosis surveillance and control could be improved by tailoring methods of diagnostic test interpretation (population level/individual level, categorical/continuous) to the situation at hand

Epidemiologically-based strategies for the detection of emerging plant pathogens

Emerging pests and pathogens of plants are a major threat to natural and managed ecosystems worldwide. Whilst it is well accepted that surveillance activities are key to both the early detection of new incursions and the ability to identify pest-free areas, the performance of these activities must be evaluated to ensure they are fit for purpose. This requires consideration of the number of potential hosts inspected or tested as well as the epidemiology of the pathogen and the detection method used. In the case of plant pathogens, one particular concern is whether the visual inspection of plant hosts for signs of disease is able to detect the presence of these pathogens at low prevalences, given that it takes time for these symptoms to develop. One such pathogen is the ST53 strain of the vector-borne bacterial pathogen Xylella fastidiosa in olive hosts, which was first identified in southern Italy in 2013. Additionally, X. fastidiosa ST53 in olive has a rapid rate of spread, which could also have important implications for surveillance. In the current study, we evaluate how well visual surveillance would be expected to perform for this pathogen and investigate whether molecular testing of either tree hosts or insect vectors offer feasible alternatives. Our results identify the main constraints to each of these strategies and can be used to inform and improve both current and future surveillance activities

Ash generation and distribution from the April-May 2010 eruption of Eyjafjallajökull, Iceland

The 39-day long eruption at the summit of Eyjafjallajökull volcano in April–May 2010 was of modest size but ash was widely dispersed. By combining data from ground surveys and remote sensing we show that the erupted material was 4.8±1.2·1011 kg (benmoreite and trachyte, dense rock equivalent volume 0.18±0.05 km3). About 20% was lava and water-transported tephra, 80% was airborne tephra (bulk volume 0.27 km3) transported by 3–10 km high plumes. The airborne tephra was mostly fine ash (diameter <1000 µm). At least 7·1010 kg (70 Tg) was very fine ash (<28 µm), several times more than previously estimated via satellite retrievals. About 50% of the tephra fell in Iceland with the remainder carried towards south and east, detected over ~7 million km2 in Europe and the North Atlantic. Of order 1010 kg (2%) are considered to have been transported longer than 600–700 km with <108 kg (<0.02%) reaching mainland Europe

Altered Patterns of Gene Expression Underlying the Enhanced Immunogenicity of Radiation-Attenuated Schistosomes

Schistosoma mansoni is a blood-dwelling parasitic worm that causes schistosomiasis in humans throughout Africa and parts of South America. A vaccine would enhance attempts to control and eradicate the disease that currently relies on treatment with a single drug. Although a manufactured vaccine has yet to generate high levels of protection, this can be achieved with infective parasite larvae that have been disabled by exposure to radiation. How these weakened parasites are able to induce protective immunity when normal parasites do not, is the question addressed by our experiments. We have used a technique of gene expression profiling to compare the patterns in normal and disabled parasites, over the period when they would trigger an immune response in the host. We found that only a handful of genes were differentially expressed, all of them diminished in the disabled parasite. However, a more sensitive technique to examine groups of genes revealed that those involved in nervous system and muscle function were depressed in the disabled parasites. We suggest that reduced mobility of these larvae permits them longer contact with the immune system, thus enabling a strong protective immune response to develop

Future developments in modelling and monitoring of volcanic ash clouds : outcomes from the first IAVCEI-WMO workshop on Ash Dispersal Forecast and Civil Aviation

As a result of the serious consequences of the 2010 Eyjafjallajökull eruption (Iceland) on civil aviation, 52 volcanologists, meteorologists, atmospheric dispersion modellers and space and ground-based monitoring specialists from 12 different countries (including representatives from 6 Volcanic Ash Advisory Centres and related institutions) gathered to discuss the needs of the ash dispersal modelling community, investigate new data-acquisition strategies (i.e. quantitative measurements and observations) and discuss how to improve communication between the research community and institutions with an operational mandate. Based on a dedicated benchmark exercise and on 3 days of in-depth discussion, recommendations have been made for future model improvements, new strategies of ash cloud forecasting, multidisciplinary data acquisition and more efficient communication between different communities. Issues addressed in the workshop include ash dispersal modelling, uncertainty, ensemble forecasting, combining dispersal models and observations, sensitivity analysis, model variability, data acquisition, pre-eruption forecasting, first simulation and data assimilation, research priorities and new communication strategies to improve information flow and operational routines. As a main conclusion, model developers, meteorologists, volcanologists and stakeholders need to work closely together to develop new and improved strategies for ash dispersal forecasting and, in particular, to: (1) improve the definition of the source term, (2) design models and forecasting strategies that can better characterize uncertainties, (3) explore and identify the best ensemble strategies that can be adapted to ash dispersal forecasting, (4) identify optimized strategies for the combination of models and observations and (5) implement new critical operational strategies