716 research outputs found
Mammal records verification rule sets for NBN Record Cleaner and recommendations on species whose records should be treated as sensitive
Abiotic and biotic factors associated with tick population dynamics on a mammalian host: Ixodes hexagonus infesting otters, Lutra lutra
The Eurasian otter, Lutra lutra, hosts several parasites with zoonotic potential. As this semiaquatic mammal has large ranges across terrestrial, freshwater and marine habitats, it has the capacity for wide dispersion of pathogens. Despite this, parasites of otters have received relatively little attention. Here, we examine their ectoparasite load and assess whether this is influenced by abiotic or biotic variables. Climatic phenomena such as the North Atlantic Oscillation (NAO) affect weather conditions in northern Europe. Consequently parasite distributions, particularly species with life stages exposed to the external environment, can be affected. We assessed the extent to which inter-annual variations in large-scale weather patterns (specifically the NAO and Central England (CE) temperatures) and host characteristics influenced tick prevalence and intensity. Ectoparasites consisted of a single species, the nidiculous tick Ixodes hexagonus (prevalence = 24.3%; mean intensity = 7.2; range = 1ā122; on n = 820 otter hosts). The prevalence, but not intensity of infestation, was associated with high CE temperatures, while both prevalence and intensity were associated with positive phases of the NAO. Such associations indicate that I. hexagonus are most abundant when weather conditions are warmer and wetter. Ticks were more prevalent on juvenile than sub-adult or adult otters, which probably reflects the length of time the hosts spend in the holt where these ticks quest. High tick number was associated with poor host condition, so either poor condition hosts are more susceptible to ticks, or tick infestations negatively impact on host condition. Otters are clearly an important and common host for I. hexagonus, which has implications for vector-borne diseases. This work is the first to consider the impacts of long-term weather patterns on I. hexagonus and uses wild-animal cadavers to illustrate the importance of abiotic and biotic pressures impacting parasitic populations
Odour dialects among wild mammals
Across multiple taxa, population structure and dynamics depend on effective signalling between individuals. Among mammals, chemical communication is arguably the most important sense, underpinning mate choice, parental care, territoriality and even disease transmission. There is a growing body of evidence that odours signal genetic information that may confer considerable benefits including inbreeding avoidance and nepotism. To date, however, there has been no clear evidence that odours encode population-level information in wild mammals. Here we demonstrate for the first time the existence of āodour dialectsā in genetically distinct mammalian subpopulations across a large geographical scale. We found that otters, Lutra lutra, from across the United Kingdom possess sex and biogeography-specific odours. Subpopulations with the most distinctive odour profiles are also the most genetically diverse but not the most genetically differentiated. Furthermore, geographic distance between individuals does not explain regional odour differences, refuting other potential explanations such as group odour sharing behaviour. Differences in the language of odours between subpopulations have the potential to affect individual interactions, which could impact reproduction and gene-flow
Spatial and seasonal factors are key determinants in the aggregation of helminths in their definitive hosts: Pseudamphistomum truncatum in otters (Lutra lutra)
Parasites are typically aggregated within their host populations. The most heavily infected hosts are frequently
cited as targets for optimal disease control. Yet a heavily infected individual is not necessarily
highly infective and does not automatically contribute a higher proportion of infective parasitic stages
than a host with fewer parasites. Here, Pseudamphistomum truncatum (Opisthorchiida) parasitic infection
within the definitive otter host (Lutra lutra) is used as a model system. The hypothesis tested is that variation
in parasite abundance, aggregation and egg production (fecundity, as a proxy of host infectivity)
can be explained by abiotic (season and region) or biotic (host age, sex and body condition) factors. Parasite
abundance was affected most strongly by the biotic factors of age and body condition, such that
adults and otters with a higher condition index had heavier infections than sub-adults or those with a
lower condition index, whilst there were no significant differences in parasite abundance among the seasons,
regions (ecological regions defined by river catchment boundaries) or host sexes. Conversely, parasite
aggregation was affected most strongly by the abiotic factors of season and region, which were
supported by four different measures of parasite aggregation (the corrected moment estimate k, Taylorās
Power Law, the Index of Discrepancy D, and Boulinierās J). Pseudamphistomum truncatum was highly
aggregated within otters, with aggregation stronger in the Midlands (England) and Wales than in the
southwestern region of the United Kingdom. Overall, more parasites were found in fewer hosts during
the summer, which coincides with the summer peak in parasite fecundity. Combined, these data suggest
that (i) few otters carry the majority of P. truncatum parasites and that there are more infective stages
(eggs) produced during summer; and (ii) abiotic factors are most influential when describing parasite
aggregation whilst biotic factors have a greater role in defining parasite abundance. Together, parasite
abundance, aggregation and fecundity can help predict which hosts make the largest contribution to
the spread of infectious diseases
Better sturdy or slender? Eurasian otter skull plasticity in response to feeding ecology
Otters are semi-aquatic mammals specialized in feeding on aquatic prey. The Eurasian otter Lutra lutra is the most widely distributed otter species. Despite a low degree of genetic variation across its European range, the population from Great Britain exhibits distinct genetic structuring. We examined 43 skulls of adult Eurasian otters belonging to 18 sampling localities and three genetic clusters (Shetlands, Wales and Scotland). For each sample location, information regarding climate was described using bioclimatic variables from WorldClim, and information on otter diet was extracted from the literature. By using photogrammetry, 3D models were obtained for each skull. To explore any evidence of adaptive divergence within these areas we used a three dimensional geometric morphometric approach to test differences in skull size and shape between areas with genetically distinct populations, as well as the influence of diet, isolation by distance and climate. Males were significantly larger in skull size than females across all the three genetic clusters. Skull shape, but not size, appeared to differ significantly among genetic clusters, with otters from Shetland exhibiting wider zygomatic arches and longer snouts compared to otters from Wales, whereas otters from Scotland displayed intermediate traits. A significant relationship could also be found between skull shape variation, diet as well as climate. Specifically, otters feeding on freshwater fish had more slender and short-snouted skulls compared to otters feeding mostly on marine fish. Individuals living along the coast are characterised by a mixed feeding regime based on marine fish and crustaceans and their skull showed an intermediate shape. Coastal and island otters also had larger orbits and eyes more oriented toward the ground, a larger nasal cavity, and a larger distance between postorbital processes and zygomatic arch. These functional traits could also represent an adaptation to favour the duration and depth of diving, while the slender skull of freshwater feeding otters could improve the hydrodynamics
The predictive role of symptoms in COVID-19 diagnostic models : A longitudinal insight
Acknowledgements 2019nCoV-302 Study Group Members: The NVX-CoV2373-2019nCoV-302 clinical trial was a collective group effort across multiple institutions and locations. Below is a list of sites and staff that significantly contributed to the implementation and conduct of the NVX-CoV2373-2019nCoV-302 clinical trial.Peer reviewe
Safety and Efficacy of the NVX-CoV2373 Coronavirus Disease 2019 Vaccine at Completion of the Placebo-Controlled Phase of a Randomized Controlled Trial
Acknowledgements The study and article were funded by Novavax. We would like to thank all the study participants for their commitment to this study. We also acknowledge the investigators and their study teams for their hard work and dedication. In addition, we would like to thank the National Institute for Health Research, representatives from the Department of Health and Social Care laboratories and NHS Digital and the members of the UK Vaccine Task Force. Editorial support was provided by Kelly Cameron of Ashfield MedComms, an Inizio company Funding This work was funded by Novavax, and the sponsor had primary responsibility for study design, study vaccines, protocol development, study monitoring, data management, and statistical analyses. All authors reviewed and approved the manuscript before submission. LF reports a position as a prior full-time employee, now contractor to Novavax re-imbursed hourly for work performed on this study and in analyses and drafting this report. IC reports providing medical writing support for this work as an employee of NovavaxPeer reviewedPublisher PD
Health, education, and social care provision after diagnosis of childhood visual disability
Aim: To investigate the health, education, and social care provision for children newly diagnosed with visual disability.Method: This was a national prospective study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), ascertaining new diagnoses of visual impairment or severe visual impairment and blindness (SVIBL), or equivalent vi-sion. Data collection was performed by managing clinicians up to 1-year follow-up, and included health and developmental needs, and health, education, and social care provision.Results: BCVIS2 identified 784 children newly diagnosed with visual impairment/SVIBL (313 with visual impairment, 471 with SVIBL). Most children had associated systemic disorders (559 [71%], 167 [54%] with visual impairment, and 392 [84%] with SVIBL). Care from multidisciplinary teams was provided for 549 children (70%). Two-thirds (515) had not received an Education, Health, and Care Plan (EHCP). Fewer children with visual impairment had seen a specialist teacher (SVIBL 35%, visual impairment 28%, Ļ2p < 0.001), or had an EHCP (11% vs 7%, Ļ2p < 0 . 01).Interpretation: Families need additional support from managing clinicians to access recommended complex interventions such as the use of multidisciplinary teams and educational support. This need is pressing, as the population of children with visual impairment/SVIBL is expected to grow in size and complexity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited
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