Immune interactions and heterogeneity in transmission drives the pathogen-mediated invasion of grey squirrels in the UK

Mathematical models highlighted the importance of pathogen-mediated invasion, with the replacement of red squirrels by squirrelpox virus (SQPV) carrying grey squirrels in the UK, a well-known example. In this study, we combine new epidemiological models, with a range of infection characteristics, with recent longitudinal field and experimental studies on the SQPV dynamics in red and grey squirrel populations to better infer the mechanistic basis of the disease interaction. A key finding is that a model with either partial immunity or waning immunity and reinfection, where individuals become seropositive on the second exposure to infection, that up to now has been shown in experimental data only, can capture the key aspects of the field study observations. By fitting to SQPV epidemic observations in isolated red squirrel populations, we can infer that SQPV transmission between red squirrels is significantly (4×) higher than the transmission between grey squirrels and as a result our model shows that disease-mediated replacement of red squirrels by greys is considerably more rapid than replacement in the absence of SQPV. Our findings recover the key results of the previous model studies, which highlights the value of simple strategic models that are appropriate when there are limited data, but also emphasise the likely complexity of immune interactions in wildlife disease and how models can help infer disease processes from field data.</p

Streptococcus pyogenes pSM19035 requires dynamic assembly of ATP-bound ParA and ParB on parS DNA during plasmid segregation

The accurate partitioning of Firmicute plasmid pSM19035 at cell division depends on ATP binding and hydrolysis by homodimeric ATPase δ2 (ParA) and binding of ω2 (ParB) to its cognate parS DNA. The 1.83 Å resolution crystal structure of δ2 in a complex with non-hydrolyzable ATPγS reveals a unique ParA dimer assembly that permits nucleotide exchange without requiring dissociation into monomers. In vitro, δ2 had minimal ATPase activity in the absence of ω2 and parS DNA. However, stoichiometric amounts of ω2 and parS DNA stimulated the δ2 ATPase activity and mediated plasmid pairing, whereas at high (4:1) ω2 : δ2 ratios, stimulation of the ATPase activity was reduced and δ2 polymerized onto DNA. Stimulation of the δ2 ATPase activity and its polymerization on DNA required ability of ω2 to bind parS DNA and its N-terminus. In vivo experiments showed that δ2 alone associated with the nucleoid, and in the presence of ω2 and parS DNA, δ2 oscillated between the nucleoid and the cell poles and formed spiral-like structures. Our studies indicate that the molar ω2 : δ2 ratio regulates the polymerization properties of (δ•ATP•Mg2+)2 on and depolymerization from parS DNA, thereby controlling the temporal and spatial segregation of pSM19035 before cell division

Squirrelpox in a red squirrel in Fife

SQUIRRELPOX has been identified as a key factor in red squirrel (Sciurus vulgaris) decline in the UK.1 Grey squirrels (Sciurus carolinensis) are thought to act as reservoir hosts for squirrelpox virus (SQPV), the causative agent of squirrelpox, with a reported asymptomatic seroprevalence of 61 per cent.2SQPV is implicated in the complete replacement of red squirrels by grey squirrels throughout mainland England and Wales,1 and poses a major threat to Scottish red squirrel populations since being first detected in 2007.3 To combat this threat, an mortality surveillance programme has been established at the Royal (Dick) School of Veterinary Studies, University of Edinburgh, using opportunistic sampling of red squirrel carcases. This has been ongoing for several years, including a summary publication covering 262 cases submitted from 2005 to 2009.4As part of this monitoring programme, an adult female red squirrel carcase was submitted by a member of the public, after having been found in Townhall Wood (NT110894), on the outskirts of Dunfermline, Fife, in March 2024. Postmortem examination identified multiple lesions typically associated with squirrelpox, including ulcerative and exudative dermatitis of the periocular and perioral skin (Fig 1). Histopathology of the affected skin identified extensive ulceration alongside remnant areas of epithelium with marked ballooning degeneration and eosinophilic intracytoplasmic inclusion bodies. Transmission electron microscopy of the affected tissue also identified numerous pox virions within the affected tissue, which through their size, shape and available surface morphology (Fig 2), were consistent with those of SQPV. In Britain there have been no additional identified diseases in red squirrels that present with periocular or perioral, ulcerative to exudative dermatitis due to a poxvirus,5indicating this case is highly likely due to SQPV.This finding represents the first identification of squirrelpox north of the central belt and is consistent with the predictions of previous modelling, which identified a high risk of northern SQPV spread from 2023 onwards.6 This modelling also suggests a rapid increase and spread of squirrelpox into more northerly and naive red squirrel populations is likely following establishment north of the central belt in central Scotland.6This case and modelling supports an increased requirement for targeted investigations, ongoing monitoring and grey squirrel interventions both around Dunfermline itself and within adjacent areas to establish the disease burden in this locality and limit further northerly squirrelpox spread.LA Wilson, veterinary pathology lecturer, M Marr, postdoctoral research fellow, C Logie, postmortem room technician, K Beckmann, conservation medicine lecturer, PWW Lurz, squirrel ecologist, R Ogden, director of conservation science, E Milne, professor emerita of veterinary clinical pathology Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG email: [email protected] DJ Everest, pathology scientist APHA Weybridge, Addlestone, Surrey KT15 3NBReferences1 Tompkins DM, White AR, Boots M. Ecological replacement of native red squirrels by invasive greys driven by disease. Ecol Lett2003;6:189–962 Sainsbury AW, Nettleton P, Gilray J, et al. Grey squirrels have high seroprevalence to a parapoxvirus associated with deaths in red squirrels. Anim Conserv2000;3:229–33 3 Mclnnes CJ, Coulter L, Dagleish MP, et al. First cases of squirrelpox in red squirrels (Sciurus vulgaris) in Scotland. Vet Rec2009;164:528–314 LaRose JP, Meredith AL, Everest DJ, et al. Epidemiological and postmortem findings in 262 red squirrels (Sciurus vulgaris) in Scotland, 2005 to 2009. Vet Rec2010;167:297–3025 Everest DJ, Tolhurst-Cherriman DAR, Davies H, et al. Assessing a potential non-invasive method for viral diagnostic purposes in European squirrels. Hystrix 2019;30:44–506 White A, Lurz PWW. A modelling assessment of control strategies to prevent/reduce squirrelpox spread. 2014. Scottish Natural Heritage Commissioned Report No 627. https://bit.ly/441TOgM (accessed 8 April 2024)PROFESSIONHistory of the veterinary professionI WRITE in response to the debate article by Bruce Vivash Jones (VR, 16/23 March 2024, vol 194, p 236). As a PhD researcher on the history of the RCVS and veterinary regulation, and a veterinary nurse, I would like to raise some issues with Vivash Jones’ historical evidence. He states that changes to the council structure would create an oligarchy. From his interpretation of an oligarchy I can assure him and our profession that the first RCVS council did work as This finding represents the first identification of squirrelpox north of the central belt20/27 April 2024 | VET RECORD312Fig 2: Squirrelpox virus virions detected in the affected tissue. Bar = 200 nmFig 1: Macroscopic lesions of ulcerative and exudative dermatitis surrounding the eye in a red squirrel (Sciurus vulgaris)Letters 20 April.indd 312Letters 20 April.indd 31216/04/2024 12:4816/04/2024 12:4

Ноосферная проблематика в философии Тейяра де Шардена

Современная экологическая ситуация остается одной их актуальных. Она требует всестороннего, комплексного анализа, в том числе и философского осмысления. В XX в. сформировались несколько концептуальных представлений, получивших название "ноосферных". Одним из теоретиков ноосферной концепции был Тейяр де Шарден. Исследование его подхода дает основание избежать ошибок и сформировать научное последовательное представление во взаимоотношениях между Природой и Обществом

Implications of squirrelpox virus for successful red squirrel translocations within mainland UK

Remnant red squirrel populations in the UK mainland are threatened by squirrelpox viral disease and the reservoir of the squirrelpox virus, the invasive grey squirrel, is expanding its range. Until this threat can be effectively mitigated, there is a high risk from disease outbreaks, following proposed conservation translocation of red squirrels

Personality traits, sex and food abundance shape space use in an arboreal mammal

Animal space use is affected by spatio-temporal variation in food availability and/or population density and varies among individuals. This inter-individual variation in spacing behaviour can be further influenced by sex, body condition, social dominance, and by the animal’s personality. We used capture-mark-recapture and radio-tracking to examine the relationship between space use and personality in Eurasian red squirrels (Sciurus vulgaris) in three conifer forests in the Italian Alps. We further explored to what extent this was influenced by changes in food abundance and/or population density. Measures of an individual’s trappability and trap diversity had high repeatability and were used in a Principal Component Analysis to obtain a single personality score representing a boldness-exploration tendency. Males increased home-range size with low food abundance and low female density, independent of their personality. However, bolder males used larger core-areas that overlapped less with other males than shy ones, suggesting different resource (food, partners) utilization strategies among personality types. For females, space use-personality relationships varied with food abundance, and bolder females used larger home ranges than shy ones at low female density, but the trend was opposite at high female density. Females’ intrasexual core-area overlap was negatively related to body mass, with no effect of personality. We conclude that relationships between personality traits and space use in free-ranging squirrels varied with sex, and were further influenced by spatio-temporal fluctuations in food availability. Moreover, different personality types (bold-explorative vs. shy) seemed to adopt different space-use strategies to increase access to food and/or partners. © 2021, The Author(s).Ministero dell’Istruzione, dell’Università e della RicercaOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Long-Term US Industrial Energy Use and CO2 Emissions

We present a description and scenario results from our recently-developed long-term model of United States industrial sector energy consumption, which we have incorporated as a module within the ObjECTS-MiniCAM integrated assessment model. This new industrial model focuses on energy technology and fuel choices over a 100 year period and allows examination of the industrial sector response to climate policies within a global modeling framework. A key challenge was to define a level of aggregation that would be able to represent the dynamics of industrial energy demand responses to prices and policies, but at a level that remains tractable over a long time frame. In our initial results, we find that electrification is an important response to a climate policy, although there are services where there are practical and economic limits to electrification, and the ability to switch to a low-carbon fuel becomes key. Cogeneration of heat and power using biomass may also play a role in reducing carbon emissions under a policy constraint