Ecological consequences of indigenous and non-indigenous freshwater fish parasites.

Parasites can have considerable consequences for their freshwater fish hosts, irrespective of whether they are intermediate or final hosts. The ecological consequences of infection arise from processes including parasite manipulation, where the parasite manipulates the host to increase their chance of transmission to the next host in the lifecycle, and parasite-mediated competition, where a consequence of infection is an alteration in the symmetry of competition between hosts and their uninfected conspecifics, or with other species. Whilst there is a great deal of existing knowledge on some of these consequences, there also remain some considerable knowledge gaps. This research covered the role of parasite exposure and water temperature on infection consequences, the foraging responses of fishes to intermediate hosts of the fish parasite Pomphorhynchus laevis that has an indigenous and non-indigenous range in Great Britain, the ecological consequences of this parasite for some freshwater fishes across these ranges, the issue of ‘enemy release’ and ‘parasite acquisition’ in introduced freshwater fishes, and the ecological consequences of infection by some native parasites for native freshwater fish. When the freshwater fish chub (Squalius cephalus) was exposed to different levels of intermediate hosts (Gammarus pulex) of P. laevis under two water temperature treatments, ambient and warmed, it revealed this interaction had considerable consequences for both parasite prevalence and the infection parameters. Whilst parasite prevalence was substantially higher at the elevated temperature, where infections did develop at lower temperatures, they were associated with fewer but larger parasites resulting in significantly higher parasite burdens, indicating complex consequences for host-parasite relationships under conditions of warming. Studies into parasite manipulation have frequently used the P. laevis: G. pulex parasite-intermediate host system for investigating how infections can result in behavioural modifications to the host that then results in their elevated risk of being predated by a fish. Here, comparative behavioural functional response experiments were used to test differences in the consumption rates of three fishes exposed to either uninfected or infected G. pulex, testing the hypothesis that the consumption rate of infected G. pulex would be significantly higher. The Type II functional response curves indicated that the results of the experiments were contrary to this hypothesis, with subsequent behavioural and foraging experiments also supporting these results. These counter-intuitive outcomes were also contrary to most other studies that suggested a parasite would manipulate its intermediate host in a way that promotes its transmission to a final host and facilitating the continuation of its life cycle. The reasons for these outputs were discussed as likely to relate to different selection pressures in this host-parasite system, given this is a generalist parasite with a wide range of potential fish final hosts. This was revealed by studies on this parasite from four fish species from five rivers that demonstrated high parasite prevalence in all species studied and suggested that small-bodied fishes, such as bullhead Cottus gobio, might play important roles in the P. laevis lifecycle. These prevalences, and the pathological consequences of the P. laevis infections, were also consistent across their indigenous and non-indigenous range, suggesting parasite origin had minimal consequences on their virulence and on the susceptibility of hosts to infection. That parasite origin often has minimal ecological consequences for their ecological impacts was reinforced by work on the ‘enemy release hypothesis’ in non-native fish in England and Wales. This revealed very few non-native parasites had been introduced with their non-native fish hosts. Those that had been introduced tended to be specialist parasites with direct lifecycles that had little opportunity to be transmitted to native fishes. Instead, the acquisition of native parasites by the non-native fishes was frequently observed, leading to potential concerns these fish would act as reservoir hosts and spill-back the parasites to the native fishes. Given the low probability of parasite introduction, the ecological consequences of three native parasites with complex lifecycles were then tested on three native fishes, and revealed consistent patterns of trophic niche divergence between infected and uninfected population sub-groups. Whilst the actual mechanism underpinning this, such as parasite-mediated competition, could not be tested, these results did reveal that the consequences of infection can be far-reaching for hosts and can be measured through a variety of methodologies. In summary, the research provided some comprehensive insights into many aspects of the pathological and ecological consequences of infection for some freshwater fishes from native/ non-native and indigenous/ non-indigenous parasites. In doing so, it has raised a series of new questions and hypotheses for further investigation, with the host-parasite systems used here capable of answering these

Diverse and complex challenges to migrant and refugee rental health: reflections of the M8 alliance expert group on migrant health

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 (6-7 June 2019) and a special session on "Protecting the Mental Health of Refugees and Migrants," 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

Zooming into plant-flower visitor networks: an individual trait-based approach

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

Reproductive ecology and diet of a persistent Ameiurus melas (Rafinesque, 1820) population in the UK

The black bullhead Ameiurus melas was introduced to Europe from North America in the early 20th Century and invasive populations are now present in many European countries (Novomesk a et al., 2013). Their invasion is assisted by their traits of high reproductive output, parental care, omnivory, aggressive behaviour and tolerance to environmental parameters (e.g. Leunda et al., 2008; Novomesk a et al., 2013). In the UK, however, they are not invasive, with only a single, persistent wild population believed to be present (Britton et al., 2010). The lag phase – the time period between the introduction of a species and an invasion developing – can be considerable for non-native fishes. For many species, its cessation requires a change in environmental conditions and/or the provision of a new dispersal opportunity (Fausch, 2007). The aim of this study was to assess the reproductive ecology and diet of A. melas in UK conditions through assessment of this persistent population. As there was only one population available, the plasticity of their traits in UK conditions could not be assessed; however, the study results are compared with their populations elsewhere. An assessment is then made to identify whether these aspects of their ecology are inhibiting their invasion of UK freshwaters. Note that Novomesk a et al. (2013) recently concluded that morphological plasticity was not a factor affecting their invasive ability and so is not considered here.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-04262016-01-31hb201

Vicariance in a generalist fish parasite driven by climate and salinity tolerance of hosts

Acanthocephalans are parasites with complex lifecycles that are important components of aquatic systems and are often model species for parasite-mediated host manipulation. Genetic characterisation has recently resurrected Pomphorhynchus tereticollis as a distinct species from Pomphorhynchus 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 that P. tereticollis was the only Pomphorhynchus parasite present in Britain, rather than P. laevis as previously recorded. A meta-analysis using two genetic regions and all the DNA sequences Abstract: available for P. tereticollis has identified two distinct genetic lineages of P. tereticollis in Britain. One lineage, possibly associated with cold water tolerant fish, potentially spread to the northern parts of Britain from the Baltic region via a 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 later via the 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

Parasites of non-native freshwater fishes introduced into england and wales suggest enemy release and parasite acquisition

When non-native species are introduced into a new range, their parasites can also be introduced, with these potentially spilling-over into native hosts. However, in general, evidence suggests that a high proportion of their native parasites are lost during introduction and infections by some new parasites from the native range might occur, potentially resulting in parasite spill-back to native species. These processes were investigated here using parasite surveys and literature review on seven non-native freshwater fishes introduced into England and Wales. Comparison of the mean numbers of parasite species and genera per population for each fish species England andWaleswith their native ranges revealed\9 % of the native parasite fauna were present in their populations in England and Wales. There was no evidence suggesting these introduced parasites had spilled over into sympatric native fishes. The non-native fishes did acquire parasites following their introduction, providing potential for parasite spill-back to sympatric fishes, and resulted in non-significant differences in overall mean numbers of parasites per populations between the two ranges. Through this acquisition, the non-native fishes also had mean numbers of parasite species and genera per population that were not significantly different to sympatric native fishes. Thus, the non-native fishes in England and Wales showed evidence of enemy release, acquired new parasites following introduction providing potential for spill-back, but showed no evidence of parasite spill-over

Precision global health: a roadmap for augmented action

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

Interactions of warming and exposure affect susceptibility to parasite infection in a temperate fish species.

Predicting 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

The role of digital technologies in tackling the Zika outbreak: a scoping review

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

Critical reflections, challenges and solutions for migrant and refugee health: 2nd M8 Alliance Expert Meeting

Abstract 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