Behavioural traits of rainbow trout and brown trout may help explain their differing invasion success and impacts

Animal behaviour is increasingly recognised as critical to the prediction of non-native species success and impacts. Rainbow trout and brown trout have been introduced globally, but there appear to be differences in their patterns of invasiveness and ecological impact. Here, we investigated whether diploid rainbow trout and diploid and triploid brown trout differ among several key behavioural measures linked to invasiveness and impact. We assessed activity, boldness, aggression, and feeding, using open field, novel object, shelter, mirror, feeding, and functional response experiments. We also tested within each fish type for behavioural syndromes comprising correlations among activity, boldness and aggression. Rainbow trout were more active and aggressive but less bold than diploid and triploid brown trout. In small groups, however, rainbow trout were bolder than both types of brown trout. Diploid brown trout were more active and bolder than triploids when tested individually, and had a higher functional response than both rainbow trout and triploid brown trout. In terms of behavioural syndromes, there was no association between activity and boldness in rainbow trout, however, there was in both brown trout types. The increased activity and aggression of rainbow trout may reflect an increased stress response to novel situations, with this response reduced in a group. These results suggest that rainbow trout do not manage their energy budgets effectively, and may explain why they have limited survival as invaders. In addition, the lower functional response of rainbow trout may explain why they are implicated in fewer ecological impacts, and the triploidy treatment also appears to lower the potential impact of brown trout. Comparative analyses of multiple behaviours of invasive species and genetic variants may thus be key to understanding and predicting invader success and ecological impacts

Behavioural traits of rainbow trout and brown trout may help explain their differing invasion success and impacts

Publication history: Accepted - 11 Jaunary 2022; Published - 2 February 2022.Animal behaviour is increasingly recognised as critical to the prediction of non-native species success and impacts. Rainbow trout and brown trout have been introduced globally, but there appear to be differences in their patterns of invasiveness and ecological impact. Here, we investigated whether diploid rainbow trout and diploid and triploid brown trout differ among several key behavioural measures linked to invasiveness and impact. We assessed activity, boldness, aggression, and feeding, using open field, novel object, shelter, mirror, feeding, and functional response experiments. We also tested within each fish type for behavioural syndromes comprising correlations among activity, boldness and aggression. Rainbow trout were more active and aggressive but less bold than diploid and triploid brown trout. In small groups, however, rainbow trout were bolder than both types of brown trout. Diploid brown trout were more active and bolder than triploids when tested individually, and had a higher functional response than both rainbow trout and triploid brown trout. In terms of behavioural syndromes, there was no association between activity and boldness in rainbow trout, however, there was in both brown trout types. The increased activity and aggression of rainbow trout may reflect an increased stress response to novel situations, with this response reduced in a group. These results suggest that rainbow trout do not manage their energy budgets effectively, and may explain why they have limited survival as invaders. In addition, the lower functional response of rainbow trout may explain why they are implicated in fewer ecological impacts, and the triploidy treatment also appears to lower the potential impact of brown trout. Comparative analyses of multiple behaviours of invasive species and genetic variants may thus be key to understanding and predicting invader success and ecological impacts.Department of Agriculture, Environment and Rural Affairs. Thanks also to the Natural Environment Research Council (NERC) and Biotechnology and Biological Sciences Research Council (BBSRC)

Carer administration of as-needed sub-cutaneous medication for breakthrough symptoms in people dying at home: the CARiAD feasibility RCT

Background Most people who are dying want to be cared for at home, but only half of them achieve this. The likelihood of a home death often depends on the availability of able and willing lay carers. When people who are dying are unable to take oral medication, injectable medication is used. When top-up medication is required, a health-care professional travels to the dying person’s home, which may delay symptom relief. The administration of subcutaneous medication by lay carers, although not widespread UK practice, has proven to be key in achieving better symptom control for those dying at home in other countries. Objectives To determine if carer administration of as-needed subcutaneous medication for common breakthrough symptoms in people dying at home is feasible and acceptable in the UK, and if it would be feasible to test this intervention in a future definitive randomised controlled trial. Design We conducted a two-arm, parallel-group, individually randomised, open pilot trial of the intervention versus usual care, with a 1 : 1 allocation ratio, using convergent mixed methods. Setting Home-based care without 24/7 paid care provision, in three UK sites. Participants Participants were dyads of adult patients and carers: patients in the last weeks of their life who wished to die at home and lay carers who were willing to be trained to give subcutaneous medication. Strict risk assessment criteria needed to be met before approach, including known history of substance abuse or carer ability to be trained to competency. Intervention Intervention-group carers received training by local nurses using a manualised training package. Main outcome measures Quantitative data were collected at baseline and 6–8 weeks post bereavement and via carer diaries. Interviews with carers and health-care professionals explored attitudes to, experiences of and preferences for giving subcutaneous medication and experience of trial processes. The main outcomes of interest were feasibility, acceptability, recruitment rates, attrition and selection of the most appropriate outcome measures. Results In total, 40 out of 101 eligible dyads were recruited (39.6%), which met the feasibility criterion of recruiting > 30% of eligible dyads. The expected recruitment target (≈50 dyads) was not reached, as fewer than expected participants were identified. Although the overall retention rate was 55% (22/40), this was substantially unbalanced [30% (6/20) usual care and 80% (16/20) intervention]. The feasibility criterion of > 40% retention was, therefore, considered not met. A total of 12 carers (intervention, n = 10; usual care, n = 2) and 20 health-care professionals were interviewed. The intervention was considered acceptable, feasible and safe in the small study population. The context of the feasibility study was not ideal, as district nurses were seriously overstretched and unfamiliar with research methods. A disparity in readiness to consider the intervention was demonstrated between carers and health-care professionals. Findings showed that there were methodological and ethics issues pertaining to researching last days of life care. Conclusion The success of a future definitive trial is uncertain because of equivocal results in the progression criteria, particularly poor recruitment overall and a low retention rate in the usual-care group. Future work regarding the intervention should include understanding the context of UK areas where this has been adopted, ascertaining wider public views and exploring health-care professional views on burden and risk in the NHS context. There should be consideration of the need for national policy and of the most appropriate quantitative outcome measures to use. This will help to ascertain if there are unanswered questions to be studied in a trial. Trial registration Current Controlled Trials ISRCTN11211024. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 25. See the NIHR Journals Library website for further project information

Prevalence of persistent SARS-CoV-2 in a large community surveillance study

Persistent SARS-CoV-2 infections may act as viral reservoirs that could seed future outbreaks 1–5, give rise to highly divergent lineages 6–8, and contribute to cases with post-acute COVID-19 sequelae (Long Covid) 9,10. However, the population prevalence of persistent infections, their viral load kinetics, and evolutionary dynamics over the course of infections remain largely unknown. Using viral sequence data collected as part of a national infection survey, we identified 381 individuals with SARS-CoV-2 RNA at high titre persisting for at least 30 days, of which 54 had viral RNA persisting at least 60 days. We refer to these as ‘persistent infections’ since available evidence suggests they represent ongoing viral replication, although the persistence of non-replicating RNA cannot be ruled out in all. Persistently infected individuals had more than 50% higher odds of self-reporting Long Covid compared to non-persistently infected individuals. We estimate that 0.1- 0.5% of infections may become persistent with typically rebounding high viral loads and last for at least 60 days. In some individuals, we identified many viral amino acid substitutions, indicating periods of strong positive selection, while others had no consensus change in the sequences for prolonged periods, consistent with weak selection. Substitutions included mutations that are lineage-defining for SARS-CoV-2 variants, at target sites for monoclonal antibodies, and/or commonly found in immunocompromised patients 11–14. This work has significant implications for understanding and characterising SARS-CoV-2 infection, epidemiology, and evolution

Lineage replacement and evolution captured by 3 years of the United Kingdom Coronavirus (COVID-19) Infection Survey

The Office for National Statistics Coronavirus (COVID-19) Infection Survey (ONS-CIS) is the largest surveillance study of SARS-CoV-2 positivity in the community, and collected data on the United Kingdom (UK) epidemic from April 2020 until March 2023 before being paused. Here, we report on the epidemiological and evolutionary dynamics of SARS-CoV-2 determined by analysing the sequenced samples collected by the ONS-CIS during this period. We observed a series of sweeps or partial sweeps, with each sweeping lineage having a distinct growth advantage compared to their predecessors, although this was also accompanied by a gradual fall in average viral burdens from June 2021 to March 2023. The sweeps also generated an alternating pattern in which most samples had either S-gene target failure (SGTF) or non-SGTF over time. Evolution was characterized by steadily increasing divergence and diversity within lineages, but with step increases in divergence associated with each sweeping major lineage. This led to a faster overall rate of evolution when measured at the between-lineage level compared to within lineages, and fluctuating levels of diversity. These observations highlight the value of viral sequencing integrated into community surveillance studies to monitor the viral epidemiology and evolution of SARS-CoV-2, and potentially other pathogens

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Traditional Excluding Forces: A Review of the Quantitative Literature on the Economic Situation of Indigenous Peoples, Afro-Descendants, and People Living with Disability

Unequal income distribution in Latin America and the Caribbean is linked to unequal distributions of (human and physical) assets and differential access to markets and services. These circumstances, and the accompanying social tensions, need to be understood in terms of traditional fragmenting forces; the sectors of the population who experience unfavorable outcomes are also recognized by characteristics such as ethnicity, race, gender and physical disability. In addition to reviewing the general literature on social exclusion, this paper surveys several more specific topics: i) relative deprivation (in land and housing, physical infrastructure, health and income); ii) labor market issues, including access to labor markets in general, as well as informality, segregation and discrimination; iii) the transaction points of political representation, social protection and violence; and iv) areas where analysis remains weak and avenues for further research in the region

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant