Effects of Spider Venom Toxin PWTX-I (6-Hydroxytrypargine) on the Central Nervous System of Rats

The 6-hydroxytrypargine (6-HT) is an alkaloidal toxin of the group of tetrahydro-β-carbolines (THβC) isolated from the venom of the colonial spider Parawixia bistriata. These alkaloids are reversible inhibitors of the monoamine-oxidase enzyme (MAO), with hallucinogenic, tremorigenic and anxiolytic properties. The toxin 6-HT was the first THβC chemically reported in the venom of spiders; however, it was not functionally well characterized up to now. The action of 6-HT was investigated by intracerebroventricular (i.c.v.) and intravenous (i.v.) applications of the toxin in adult male Wistar rats, followed by the monitoring of the expression of fos-protein, combined with the use of double labeling immunehistochemistry protocols for the detection of some nervous receptors and enzymes related to the metabolism of neurotransmitters in the central nervous system (CNS). We also investigated the epileptiform activity in presence of this toxin. The assays were carried out in normal hippocampal neurons and also in a model of chronic epilepsy obtained by the use of neurons incubated in free-magnesium artificial cerebro-spinal fluid (ACSF). Trypargine, a well known THβC toxin, was used as standard compound for comparative purposes. Fos-immunoreactive cells (fos-ir) were observed in hypothalamic and thalamic areas, while the double-labeling identified nervous receptors of the sub-types rGlu2/3 and NMR1, and orexinergic neurons. The 6-HT was administrated by perfusion and ejection in “brain slices” of hippocampus, inducing epileptic activity after its administration; the toxin was not able to block the epileptogenic crisis observed in the chronic model of the epilepsy, suggesting that 6-HT did not block the overactive GluRs responsible for this epileptic activity

Large scale spatio-temporal modelling of risk factors associated with tuberculosis exposure at the wildlife-livestock interface

The management of animal tuberculosis (TB) is a priority for European Union animal health authorities. However, and despite all the efforts made to date, a significant part of Spain has as yet been unable to obtain the officially tuberculosis-free (OTF) status. Information regarding wildlife disease status is usually scarce, signifying that the role played by wildlife is usually ignored or poorly assessed in large-scale TB risk factor studies. The National Wildlife Health Surveillance Plan in Spain now provides information on infection rates in wildlife reservoirs at a national level, but there are limitations as regards the sample size, the spatio-temporal distribution of the samples, and the lack of homogeneity of the diagnostic techniques employed. The objective of the study described herein was, therefore, to employ a Bayesian approach with the intention of identifying the risk factors associated with four TB rates in cattle: prevalence, incidence, maintenance and persistence in Spain during the period 2014–2019. The modeling approach included highly informative spatio-temporal latent effects with which to control the limitations of the data. Variation partitioning procedures were carried out, and the pure effect of each factor was mapped in order to identify the most relevant factors associated with TB dynamics in cattle in each region. This made it possible to disclose that the movement of cattle, particularly from counties with herd incidence > 1%, was the main driver of the TB dynamics in cattle. The abundance of herds bred for bullfighting was retained in all four models, but had less weight than the movements. After accounting for farm-related factors, the TB prevalence in wild boar was retained in all the models and was significantly related to incidence, maintenance and persistence. With regard to the incidence, variation partitioning revealed that wildlife was the most explicative factor, thus suggesting that it plays a role in the introduction of the pathogen into uninfected herds, and consequently highlighting its importance in breakdowns. These results show, for the first time on a national scale, that wild ungulates play a relevant role in the spatio-temporal variability of TB in cattle, particularly as regards their disease status. Moreover, the spatial representation of the pure effect of each factor made it possible to identify which factors are driving the disease dynamics in each region, thus showing that it is a valuable tool with which to focus efforts towards achieving the OTF status.CH is supported by a predoctoral grant funded by European Social Fund (ESF) and Castilla-La Mancha regional government (JCCM; ref: SUPLY/19/180501/000487). We would like to thank the Spanish Ministry of Agriculture, Food and Fisheries (MAPA; Ministerio de Agricultura, Pesca y Alimentación) for its continuous support by means of different contracts and data provision, and project PID2019-111699RB-I00 (Proyectos de I+D+i Retos Investigación tipo B).Peer reviewe

Spatial epidemiology of animal tuberculosis at the wildlife-livestock interface at national scale

Resumen del trabajo presentado a la Joint Virtual Conference of the WDA and EWDA, celebrada del 31 de agosto al 2 de septiembre de 2021.Peer reviewe

Disease-inducing potential of two leukemic cell lines in a xenografting model

PURPOSE: Cryopreserved ovarian tissue transplant restores ovarian function in young cancer patients after gonadotoxic treatment. However, leukemia is associated with increased risk of malignant cell transmission. We aimed to assess the tumor-inducing potential of two different leukemic cell lines when xenografted to immunodeficient mice. METHODS: Fifty-four female immunodeficient mice were grafted with either 100, 200, 500, 1000, and 10,000 chronic myeloid leukemia in blast crisis (BV-173) cells or relapsed acute lymphoblastic leukemia (RCH-ACV) cells, embedded inside a fibrin scaffold along with 50,000 human ovarian stromal cells. Two mice per cell line received the fibrin matrix without leukemic cells as negative controls. Clinical signs of disease were monitored for 20 weeks. Grafts, liver tissue, and masses were collected for macroscopic analysis and gene expression of BCR-ABL1 and E2A-PBX fusion transcripts present in BV-173 and RCH-ACV respectively. RESULTS: BV-173 cells: Mice grafted with 100, 200, or 500 cells showed no sign of disease after and were negative for BCR-ABL1 expression. Three of the 5 animals grafted with 1000 cells and all mice with 10,000 cells developed disease and showed BCR-ABL1-positive expression. RCH-ACV cells: Two out of 4 mice grafted with 100 cells developed disease and were E2A-PBX1-positive. All the animals grafted with higher cell doses showed signs of disease and all but one were E2A-PBX1-positive. CONCLUSION: The present work proves that the disease-inducing potential of BV-173 and RCH-ACV leukemic cells xenografted to SCID mouse peritoneum differs between cell lines, depending on cell number, type, status, and cytogenetic disease profile when ovarian tissue is harvested

Evaluation of a combined and portable light-ultrasound device with which to deter red deer

Human–wildlife conflicts are a growing problem in Northern Hemisphere where wild ungulates are one of the taxonomic groups most frequently involved. To mitigate these conflicts, it is essential to develop preventive actions able to avoid encounters between wildlife and human (activities). We here employed photo-trapping to evaluate the behaviour of red deer (Cervus elaphus) when confronted with dissuasive portable deterrents that function on the basis of changing patterns of light and ultrasound. This was done by following a before/after experimental design, with two phases: (i) a test phase, with active deterrents, and (ii) a control phase, without deterrents. When deterrents were activated they achieved a 48.96% reduction in the frequency of use by red deer (up to 66.64% when it was assessed on a thinner Sect. 10 m wide from the line of deterrents) and produced a reduction of 67.71% in the frequency of deterrent-line crossings. However, a habituation effect was detected since the use by red deer of the treatment area increased as time since treatment. These results indicate that these portable devices are effective as regards dissuading deer, mainly on short time scales. The deterrents tested here could be suitable for use at focal points for short periods or in combination with other methods to improve their effectiveness in vulnerability points. This device could potentially be used to mitigate conflicts caused by wildlife species and in response to relevant and timely situations, such as vehicle collisions and damage to crops, among others.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.This research was funded by VISEVER S.L. E. Laguna is supported by a predoctoral grant (Programa Talento Formación) funded by the European Social Fund (ESF) and the Castilla-La Mancha regional government (JCCM) (ref: SBPLY/16/180501/000269). P. Palencia is supported by MINECO (FPU16/00039). AJ. Carpio is supported by a ‘Juan de la Cierva’ contract (FJCI-2017–33114) from MINECO-UCLM. C. Herraiz is supported by ESF and JCCM (ref: SUPLY/19/180501/000487).Peer reviewe

Use of dynamic network in the wildlife-livestock interface to study endemic and emerging diseases

Resumen del póster presentado a la Joint Virtual Conference of the WDA and EWDA, celebrada del 31 de agosto al 2 de septiembre de 2021.Dynamic networks are an analytical tool highly valued in epidemiology due to their potential to identify individuals or communities with a key role in the transmission of pathogens. By including the temporal dimension in the analysis is possible to consider the potential process of pathogen transmission along the time. This approach becomes more necessary in those interfaces where emerging diseases mean a challenge. The objective of this work was to characterise the network of interactions in a multi-host extensive system where wild boar (Sus scrofa) and red deer (Cervus elaphus) cohabit with livestock, and to simulate the potential transmission of Mycobacterium tuberculosis complex (MTB) and African swine fever virus (ASFV) within a dynamic network. To this end 6 red deer, 6 wild boar, 3 cattle and 10 domestic pigs were collared during autumn 2017–winter 2018 using GPS and proximity devices; besides, indirect interactions between animals through water points (as a potential source of pathogens) were considered. Close interspecific interactions were found to be scarce, but water points acted as an attractant for both wildlife and livestock, resulting in a high number of interspecific indirect interactions. The simulation showed that transmission of MTB may occur preferably from red deer to cattle in our studied system; in the case of ASFV, our simulation suggests that transmission from wild boar to pigs occurs more probably through water points. The results of this preliminary work highlight the relevant role that certain wild species could play in the transmission of pathogens in multihost systems. More in deep studies are necessary to understand the real role of water points for the transmission of the two diseases considered, both for pathogen maintenance or carcasses presence. Also, more empirical data (e.g. more collared individuals) is needed to estimate more reliable rates of interactions, specifically for direct interactions.Peer reviewe

Monitorización integrada de fauna silvestre: prueba piloto de la vigilancia sanitaria del siglo XXI

Póster presentado al XV Congreso de la Sociedad Española para la Conservación y Estudio de los Mamífero (SECEM), celebrado en Córdoba del 4 al 7 de diciembre de 2021.Peer reviewe

Environmental factors driving fine-scale ixodid tick abundance patterns

Tick abundance is an essential demographic parameter to infer tick-borne pathogen transmission risks. Spatiotemporal patterns of tick abundance are heterogeneous, so its determinants at small spatial scales need to be understood to reduce their negative effects on hosts. Current knowledge of these determinants is scarce, especially in Mediterranean environments, limiting the possibilities for designing efficient tick control strategies. With the goal of unravelling tick abundance determinants and informing new tick management strategies, we estimated tick burdens on 1965 wild ungulates in Doñana National Park, Spain, annually between 2010 and 2020. Under the hypothesis of a predominant host influence on tick abundance, we modelled the burdens of Rhipicephalus annulatus, Hyalomma lusitanicum, and Ixodes ricinus with relevant predictors grouped into four factors: i) environment; ii) host population; iii) host individual; and iv) land-use. Generalized linear mixed models with a zero-inflated negative binomial distribution were built. Additionally, we analysed the differential contribution to abundance of each factor by deviance partitioning. We finally estimated the similarity in the environmental space of tick species by analysing their niche overlap with the environmental principal component analysis method. Our work hypothesis was confirmed for R. annulatus and H. lusitanicum, but we found that tick abundance at a fine spatial scale is jointly driven by multiple drivers, including all four factors considered in this study. This result points out that understanding the demography of ticks is a complex multifactorial issue, even at small spatial scales. We found no niche differences between the three tick species at the study spatial scale, thus showing similar host and environmental dependencies. Overall results identify that host aggregation areas displaying environmentally favourable traits for ticks are relevant tick and vector-borne pathogen transmission hotspots. Our findings will facilitate the design of new strategies to reduce the negative effects of tick parasitism.This study is the result of a close collaboration among predoctoral and postdoctoral researchers, field technicians and environment agents that worked together along the survey time in Doñana National Park. We would like to thank Dr. Agustín Estrada-Peña for his initial dedication to the study. We are also grateful to Dr. Joaquín Vicente from IREC for the steps taken to facilitate sampling. We acknowledge data sharing from ‘Infraestructura Científico-Técnica Singular de Doñana – ICTS-RBD’ with special gratitude to Francisco Carro.Peer reviewe