Search

Acanthocephalans are parasites with complex lifecycles that are important components of aquatic systems and are often model species for parasite-mediated host manipulation. Genetic characterization has recently resurrectedPomphorhynchus tereticollisas a distinct species fromPomphorhynchus laevis, with potential implications for fisheries management and host manipulation research. Morphological and molecular examinations of parasites from 7 English rivers across 9 fish species revealed thatP. tereticolliswas the onlyPomphorhynchusparasite present in Britain, rather thanP. laevisas previously recorded. Molecular analyses included two non-overlapping regions of the mitochondrial gene – cytochrome oxidase and generated 62 sequences for the shorter fragment (295 bp) and 74 for the larger fragment (583 bp). These were combined with 61 and 13 sequences respectively, from Genbank. A phylogenetic analysis using the two genetic regions and all the DNA sequences available forP. tereticollisidentified two distinct genetic lineages in Britain. One lineage, possibly associated with cold water tolerant fish, potentially spread to the northern parts of Britain from the Baltic regionviaa northern route across the estuarine area of what is now the North Sea during the last Glaciation. The other lineage, associated with temperate freshwater fish, may have arrived laterviathe Rhine/Thames fluvial connection during the last glaciation or early Holocene when sea levels were low. These results raise important questions on this generalist parasite and its variously environmentally adapted hosts, and especially in relation to the consequences for parasite vicariance.

Throughout recent years, we have witnessed an increase in human migration as a result of conflict, political instability and changes in the climate. Despite the growing number of migrants and refugees, provisions to address their health needs remain inadequate and often unmet. Whilst a variety of instruments exist to assert and emphasise the importance for migrant and refugee health, the lack of shared priorities between partners and stakeholders results in poor access to healthcare and essential medicines. In response to the growing health challenges faced by migrants and refugees, members of the M8 Alliance launched an annual Expert Meeting on Migrants’ and Refugees’ Health. This report is shaped by discussions from the second M8 Alliance Expert Meeting (Sapienza University of Rome, Italy, 15–16 June 2018) and is supported by supplementing literature to develop a framework addressing critical reflections, challenges and solutions of and for migrant and refugee health. This report aims to inform decision-making fostering a humanitarian, ethics and rights-based approach. Through a series of country-specific case studies and discussions, this report captures the most prominent themes and recommendations such as mental health, tuberculosis (TB) and best practices for increased access.

Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1mmolm(-2) h(-1) at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams. Diel patterns can greatly impact total stream carbon dioxide emissions, with 39% greater carbon dioxide flux during the night-time relative to the day-time, according to a study of 34 streams across Europe.

1. Many aquatic ecosystems sustain multiple invasive species and interactions among them have important implications for ecosystem structure and functioning. Here, we examine interactions among two pairs of invasive crayfish species because of their close proximity and thus chance of sympatric populations in the near future within the Thames catchment, U.K. (signal, Pacifastacus leniusculus and virile crayfish, Orconectes virilis within a river system; red swamp, Procambarus clarkii and Turkish crayfish, Astacus leptodactylus found within a suite of ponds). We address two questions: do sympatric invasive crayfish occupy a smaller niche than their allopatric counterparts due to potential resource competition? and do interactions among invasive species amplify or mitigate one another's impacts on the ecosystem? 2. Two fully factorial mesocosm experiments (one for each crayfish pair) were used to investigate crayfish diet and their impact on benthic invertebrate community structure, benthic algal standing stock and leaf litter decomposition rates in allopatric and sympatric populations, compared with a crayfish‐free control. We used stable isotope analysis to examine crayfish diet in the mesocosms and in allopatric populations of each species in the Thames catchment. 3. Isotopic niche width did not vary significantly between allopatric and sympatric populations of crayfish in the mesocosm experiments, and isotopic niche partitioning in all the wild populations suggests the invaders can coexist. 4. All four species altered benthic invertebrate community structure but with differing functional effects, often mediated via trophic cascades. Red swamp crayfish predation upon snails evidently promoted benthic algal standing stock via reduction in grazing pressure. However, a trophic cascade whereby the crayfish consumed native invertebrate shredders, causing a reduction in net leaf litter decomposition, was decoupled by red swamp and signal crayfish since they consumed leaf litter directly and thus moderated the cascade to a trickle when in sympatry with Turkish or virile crayfish, respectively. 5. Benthic invertebrate predator abundance was significantly reduced by sympatric red swamp and Turkish crayfish but not independently when in allopatry, indicating an amplified effect overall when in sympatry. 6. Our results suggest that the combined effect of multiple invasions on the ecosystem can reflect either an additive effect of their independent impacts or an amplified effect, which is greater than the sum of their independent impacts. A lack of general pattern in their effects makes any potential management strategy more complex.

In the past years, Global Health has interfaced with important challenges related to several dynamic changes. Technological progress, the digital revolution and the emergence of new actors in the field of health, increase the possibility of finding solutions to these unprecedented challenges. Starting from these assumptions, the idea of providing an adequate platform for good management of the health system has flowed into the creation of a meeting place that would allow a wide exchange of information, ideas sharing and proposals for new collaborations: the Geneva Health Forum (GHF). The GHF is a global health conference that aims to promote critical reflections and constructive debates on contemporary global health issues, thus influencing and informing policy formulation with experience from the field. The profile and impact of the Geneva Health Forum has grown year on year, establishing itself as a unique forum, ranging from more traditional sessions to innovative events.

International audience; Globally, streams represent major CO2 emitters, accounting for approximately 70% of the total flux from inland waters. Hence, a proper understanding of carbon dioxide (CO2) uptake and emissions from streams is crucial for accurately estimating aquatic global carbon emissions. However, diurnal dynamics of these fluxes are still not comprehensively quantified, contributing to a high uncertainty in regional and global carbon budgets. Within the EuroRun project, the 1st Collaborative European Freshwater Science Project for Young Researchers, we aimed to assess spatial and seasonal variability of day- and night-time CO2 fluxes of 34 streams across 11 European countries. CO2 fluxes were measured with drifting flux chambers once per season at midday and midnight. The median CO2 fluxes during the day amounted to 1.4 µmol m-2 h-1 (IQR 0.5 to 3.1) and during the night to 2.1 µmol m-2 h-1 (IQR 0.95 to 3.75). The CO2 fluxes during night exceeded those during day by up to eight times. Interestingly, these differences occurred throughout all seasons and showed no latitudinal patterns. Our results highlight the importance of night-time fluxes to accurately assess CO2 fluxes from streams. As most studies are performed during the day, our survey indicates that global carbon budgets are currently underestimating the amount of CO2 released by streams.

Forced migration is likely to continue to grow in the coming years due to climate change, disease outbreaks, conflict, and other factors. There are a huge number of challenges to maintaining good health, and specifically good mental health, among migrants at all stages of migration. It is vital to fully understand these diverse challenges so that we can work towards overcoming them. In 2017, as a response to the growing health challenges faced by migrants and refugees, the M8 Alliance created an expert group focussing on migrant and refugee health. The group meets annually at the Sapienza University of Rome, Italy, and this article is based on the discussions that took place at the third annual meeting (6&ndash, 7 June 2019) and a special session on &ldquo, Protecting the Mental Health of Refugees and Migrants,&rdquo, which took place on 27 October at the World Health Summit 2019 in Berlin. Our discussions are also supported by supplementary literature to present the diverse and complex challenges to the mental health of migrants and refugees. We conclude with some lessons learned and hope for the future.

With increased complexity in various global health challenges comes a need for increased precision and the adoption of more tailored health interventions. Building on precision public health, we propose precision global health (PGH), an approach that leverages life sciences, social sciences, and data sciences, augmented with artificial intelligence (AI), in order to identify transnational problems and deliver targeted and impactful interventions through integrated and participatory approaches. With more than four billion Internet users across the globe and the accelerating power of AI, PGH taps on our current augmented capacity to collect, integrate, analyse and visualise large volumes of data, both non-specific and specific to health. With the support of governments and donors, and together with international and non-governmental organisations, universities and research institutions can generate innovative solutions to improve health and wellbeing of the most vulnerable populations around the world. In line with the Sustainable Development Goals, we propose here a road map for the development and implementation of PGH.

Parasite manipulation of intermediate hosts evolves to increase parasite trophic transmission to final hosts, yet counter selection should act on the final host to reduce infection risk and costs. However, determining who wins this arms race and to what extent is challenging. Here, for the first time, comparative functional response analysis quantified final host consumption patterns with respect to intermediate host parasite status. Experiments used two evolutionarily experienced fish hosts and two naive hosts, and their amphipod intermediate hosts of the acanthocephalan parasite Pomphorhynchus tereticollis . The two experienced fish consumed significantly fewer infected than non-infected prey, with lower attack rates and higher handling times towards the former. Conversely, the two naive fish consumed similar numbers of infected and non-infected prey at most densities, with similar attack rates and handling times towards both. Thus, evolutionarily experienced final hosts can reduce their infection risks and costs via reduced intermediate host consumption, with this not apparent in naive hosts.

Understanding how ecological communities are structured is a major goal in ecology. Ecological networks representing interaction patterns among species have become a powerful tool to capture the mechanisms underlying plant-animal assemblages. However, these networks largely do not account for inter-individual variability and thus may be limiting our development of a clear mechanistic understanding of community structure. In this study, we develop a new individual-trait based approach to examine the importance of individual plant and pollinator functional size traits (pollinator thorax width and plant nectar holder depth) in mutualistic networks. We performed hierarchical cluster analyses to group interacting individuals into classes, according to their similarity in functional size. We then compared the structure of bee-flower networks where nodes represented either species identity or trait sets. The individual trait-based network was almost twice as nested as its species-based equivalent and it had a more symmetric linkage pattern resulting from of a high degree of size-matching. In conclusion, we show that by constructing individual trait-based networks we can reveal important patterns otherwise difficult to observe in species-based networks and thus improve our understanding of community structure. We therefore recommend using both trait-based and species-based approaches together to develop a clearer understanding of the properties of ecological networks.

The 2016 Zika outbreak in the Americas was a public health emergency of international concern. Alongside traditional approaches, several digital technologies were used to tackle this rapidly spreading global health threat. This work aimed to summarize the current state of research activity on the use of digital technologies during the Zika outbreak of 2015–2016 by providing an overview of the literature. A scoping review of publications indexed in the Web of Science and PubMed databases, published between 2016 and mid-2017 was conducted. Initial screening involved reviewing the title and abstract of identified literature before a full-text review was completed. Using a descriptive analytical method, we summarized the information presented in the studies. A total of 350 articles were screened with 57 found to describe the use of digital technologies with specific reference to the Zika outbreak. Several domains of digital technologies were identified including computational modelling (32/57), big data (including social media data) (19/57), mobile health (4/57), and other novel technologies (2/57), which were used for several purposes including disease monitoring (53/57), diagnostics (2/57) and treatment (2/57). Most articles (54/57) used a quantitative methodology. The majority of the studies (55/57) used non-experimental study designs with only two articles reporting experimental approaches. In terms of geographical focus, approximately half (27/57) of the published papers targeted the region of the Americas. This scoping review provided an overview of the current state of research on the utilization of digital technologies with specific reference to the Zika outbreak. The majority of articles reported the use of computational modelling and big data systems as core approaches, commonly dedicated to disease monitoring. Only a few studies described the use of mHealth and novel technologies. The findings indicate the potential value of digital technologies in the sphere of global health and outbreak response.

Comparative functional responses (FRs) can predict impacts of invasive species,including piscivorous fishes, via quantifying their depletion of native food resources as a function of prey density. The utility of FRs for predicting impacts on prey populations by invasive fishes of different trophic guilds was tested here by comparing the FRs of the invaders Cyprinus carpio and Carassius auratus, with three native, trophically analogous fishes, Barbus barbus, Squalius cephalus and Tinca tinca. Chironomid larvae and Gammarus pulex were used a prey items. Predictions,developed from studies on the foraging of C. carpio and C. auratus in the literature,were that the invaders would have significantly higher consumption rates for chironomids than the native fishes, but not for G. pulex. Mean consumption rates for chironomids were significantly lower for both invaders than B. barbus and S.cephalus, but were similar to T. tinca. Barbus barbus had a significantly lower consumption rate of G. pulex than both invaders, but there were no significant differences between S. cephalus, T.tinca and the invaders. All FRs were type II, with functional response curves for the invaders preying upon chironomids never being significantly higher than the native fishes, contrary to predictions. For G. pulex,some significant differences were apparent between the invaders and native fishes, but again were contrary to predictions. These results indicated that when predation impacts of invasive fishes could also be a function of their population density and body sizes, these parameters should be incorporated into FR models to improve impact predictions.

The network approach is increasingly used by food-web ecologists and ecological parasitologists and has shed light on how parasite–host assemblages are organized, as well as on the role of parasites on the structure and stability of food webs. With accelerating rates of nonnative parasites being introduced around the world, there is an increasing need to predict their ecological impacts and the network approach can be helpful in this regard. There is inherent complexity in parasite invasions as parasites are highly diverse in terms of taxa and life strategies. Furthermore, they may depend on their cointroduced host to successfully overcome some crucial steps in the invasion process. Free-living introduced species often experience enemy release during invasion, which reduces the number of introduced parasites. However, introduced parasites that successfully establish may alter the structure of the recipient network through various mechanisms including parasite spill-over and spill-back, and manipulative and nonmanipulative phenotypic alterations. Despite limited literature on biological invasions in infectious food webs, some outstanding methodological issues and the considerable knowledge gaps that remain, the network approach provides valuable insights on some challenging questions, such as the link between structure and invasibility by parasites. Additional empirical data and theoretical investigations are needed to go further and the predictive power of the network approach will be improved by incorporating weighted methods that are based on trophic data collected using quantitative methods, such as stable isotope analyses.

SUMMARYPredicting how elevated temperatures from climate change alter host–parasite interactions requires understandings of how warming affects host susceptibility and parasite virulence. Here, the effect of elevated water temperature and parasite exposure level was tested on parasite prevalence, abundance and burden, and on fish growth, using Pomphorhynchus laevis and its fish host Squalius cephalus. At 60 days post-exposure, prevalence was higher at the elevated temperature (22 °C) than ambient temperature (18 °C), with infections achieved at considerably lower levels of exposure. Whilst parasite number was significantly higher in infected fish at 22 °C, both mean parasite weight and parasite burden was significantly higher at 18 °C. There were, however, no significant relationships between fish growth rate and temperature, parasite exposure, and the infection parameters. Thus, whilst elevated temperature significantly influenced parasite infection rates, it also impacted parasite development rates, suggesting warming could have complex implications for parasite dynamics and host resistance.

1. Ecological theory attempts to predict how impacts for native species arise from biological invasions. A fundamental question centres on the feeding interactions of invasive and native species: whether invasion will result in increased interspecific competition, which would result in negative consequences for the competing species, or trophic niche divergence, which would facilitate the invader’s integration into the community and their coexistence with native species. 2. Here, the feeding interactions of a highly invasive fish, topmouth gudgeon Pseudorasbora parva, with three native and functionally similar fishes were studied to determine whether patterns of either niche overlap or divergence detected in mesocosm experiments were apparent between the species at larger spatial scales. Using stable isotope analysis, their feeding relationships were assessed initially in the mesocosms (1000 L) and then in small ponds (600 m2). 3. In the mesocosms, a consistent pattern of trophic niche divergence was evident between the sympatric fishes, with niches shifting further apart in isotopic space than suggested in allopatry, revealing that sharing of food resources was limited. Sympatric P. parva also had a smaller niche than their allopatric populations. 4. In eight small ponds where P. parva had coexisted for several years with at least one of the fish species used in the mesocosms, strong patterns of niche differentiation were also apparent, with P. parva always at a lower trophic position than the other fishes, as also occurred in the mesocosms. Where these fishes were sympatric within more complex fish communities in the large ponds, similar patterns were also apparent, with strong evidence of trophic niche differentiation. 5. Aspects of the ecological impacts of P. parva invasion for native communities in larger ponds were consistent with those in the mesocosm experiments. Their invasion resulted in divergence in trophic niches, partly due to their reduced niche widths when in sympatry with other species, facilitating their coexistence in invaded ecosystems. Our study highlights the utility of controlled mesocosm studies for predicting the trophic relationships that can develop from introductions of non-native species into more complex ecosystems and at larger spatial scales.