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Johne's disease (JD), a chronic, infectious enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP), affects wild and domestic ruminants. There is no cure or effective prevention, and current vaccines have substantial limitations, leaving this disease widespread in all substantial dairy industries causing economic, and animal welfare implications. Mycobacteriophages (MPs) have been gaining interest in recent years and are proposed as a promising solution to curtailing MAP infection. Using a well-validated infection model, we have demonstrated the preventative potential of MPs to protect dairy calves against MAP infection. Calves were supplemented daily with a phage cocktail from birth till weaning at 2 m of age and inoculated with MAP at 2 wk of age. Infection status was measured for 4.5 mo through blood, fecal, and postmortem tissue samples. Our findings highlight the remarkable efficacy of orally administered MPs. Notably, fecal shedding of MAP was entirely eliminated within 10 wk, in contrast to the infected control group where shedding continued for the entirety of the trial period. Postmortem tissue culture analysis further supported the effectiveness of MPs, with only 1 out of 6 animals in the phage-treated group testing positive for MAP colonized tissues compared to 6 out of 6 animals in the infected control group. Additionally, plaque assay results demonstrated the ability of phages to persist within the intestinal tract. Collectively, these results underscore the potential of orally administered MP cocktails as a highly effective intervention strategy to combat JD in dairy calves and by extension in the dairy industry.
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Enfermedades de los Bovinos , Heces , Intestino Delgado , Micobacteriófagos , Mycobacterium avium subsp. paratuberculosis , Paratuberculosis , Animales , Paratuberculosis/prevención & control , Paratuberculosis/microbiología , Bovinos , Heces/microbiología , Heces/virología , Micobacteriófagos/fisiología , Enfermedades de los Bovinos/microbiología , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/virología , Intestino Delgado/microbiología , Intestino Delgado/virología , Derrame de BacteriasRESUMEN
Indoor superspreading events are significant drivers of transmission of respiratory diseases. In this work, we study the dynamics of airborne transmission in consecutive meetings of individuals in enclosed spaces. In contrast to the usual pairwise-interaction models of infection where effective contacts transmit the disease, we focus on group interactions where individuals with distinct health states meet simultaneously. Specifically, the disease is transmitted by infected individuals exhaling droplets (contributing to the viral load in the closed space) and susceptible ones inhaling the contaminated air. We propose a modeling framework that couples the fast dynamics of the viral load attained over meetings in enclosed spaces and the slow dynamics of disease progression at the population level. Our modeling framework incorporates the multiple time scales involved in different setups in which indoor events may happen, from single-time events to events hosting multiple meetings per day, over many days. We present theoretical and numerical results of trade-offs between the room characteristics (ventilation system efficiency and air mass) and the group's behavioral and composition characteristics (group size, mask compliance, testing, meeting time, and break times), that inform indoor policies to achieve disease control in closed environments through different pathways. Our results emphasize the impact of break times, mask-wearing, and testing on facilitating the conditions to achieve disease control. We study scenarios of different break times, mask compliance, and testing. We also derive policy guidelines to contain the infection rate under a certain threshold.
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Contaminación del Aire Interior , Contaminación del Aire , HumanosRESUMEN
Sclerotinia disease is one of the most devastating fungal diseases worldwide, as it reduces the yields of many economically important crops. Pathogen-secreted effectors play crucial roles in infection processes. However, key effectors of Ciboria shiraiana, the pathogen primarily responsible for sclerotinia disease in mulberry (Morus spp.), remain poorly understood. In this study, we identified and functionally characterized the effector Cs02526 in C. shiraiana and found that Cs02526 could induce cell deathin a variety of plants. Moreover, Cs02526-induced cell death was mediated by the central immune regulator BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 (BAK1), dependent on a 67-amino acid fragment. Notably, Cs02526 homologues were widely distributed in hemibiotrophic and necrotrophic phytopathogenic fungi, but the homologues failed to induce cell death in plants. Pre-treatment of plants with recombinant Cs02526 protein enhanced resistance against both C. shiraiana and Sclerotinia sclerotiorum. Furthermore, the pathogenicity of C. shiraiana was diminished upon spraying plants with synthetic dsRNA-Cs02526. In conclusion, our findings highlight the cell death-inducing effector Cs02526 as a potential target for future biological control strategies against plant diseases.
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Hitherto no therapeutic has received regulatory approval for the treatment of post-COVID-19 condition (PCC). Cognitive deficits, mood symptoms and significant reduction in health-related quality of life (HRQoL) are highly replicated and debilitating aspects of PCC. We sought to determine the impact of vortioxetine on the foregoing symptoms and HRQoL in persons living with PCC. An 8-week randomized, double-blind, placebo-controlled study of adults ≥ 18 years of age residing in Canada and who are experiencing symptoms of World Health Organization (WHO)-defined PCC, with a history of confirmed SARS-CoV-2 infection, was conducted. Recruitment began November 2021 and ended January 2023. Of the 200 participants enrolled (487 invited: 121 ineligible and 59 eligible but declined participation; 307 cleared pre-screening stage), a total of 149 participants were randomized (1:1) to receive either vortioxetine (5-20â mg, n = 75) or placebo (n = 74) daily for 8 weeks of double-blind treatment (i.e. end point). The primary outcome was the change from baseline-to-end point in the Digit Symbol Substitution Test. Secondary outcomes included the effect on depressive symptoms and HRQoL, as measured by changes from baseline-to-end point on the Quick Inventory of Depressive Symptomatology 16-item and WHO Wellbeing Scale 5-item, respectively. A total of 68 (90.7%) participants randomized to vortioxetine and 73 (98.6%) participants randomized to placebo completed all 8 weeks. Between-group analysis did not show a significant difference in the overall change in cognitive function [P = 0.361, 95% confidence interval (CI) (-0.179, 0.492)]. However, in the fully adjusted model, a significant treatment × time interaction was observed in favour of vortioxetine treatment with baseline c-reactive protein (CRP) as a moderator (P = 0.012). In addition, a significant improvement in Digit Symbol Substitution Test scores were observed in vortioxetine versus placebo treated participants in those whose baseline CRP was above the mean (P = 0.045). Moreover, significant improvement was obtained in measures of depressive symptoms [P < 0.001, 95% CI (-4.378, -2.323)] and HRQoL [P < 0.001, 95% CI (2.297, 4.647)] in vortioxetine-treated participants and between the treatment groups [depressive symptoms: P = 0.026, 95% CI (-2.847, -0.185); HRQoL: P = 0.004, 95% CI (0.774, 3.938)]. Although vortioxetine did not improve cognitive function in the unadjusted model, when adjusting for CRP, a significant pro-cognitive effect was observed; antidepressant effects and improvement in HRQoL in this debilitating disorder were also noted.
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COVID-19 , Adulto , Humanos , Vortioxetina/uso terapéutico , Calidad de Vida , SARS-CoV-2 , Síndrome Post Agudo de COVID-19 , Proteína C-ReactivaRESUMEN
Mutations allowing pathogens to escape host immunity promote the spread of infectious diseases in heterogeneous host populations and can lead to major epidemics. Understanding the conditions that slow down this evolution is key for the development of durable control strategies against pathogens. Here, we use theory and experiments to compare the efficacy of three strategies for the deployment of resistance: (i) a mixing strategy where the host population contains two single-resistant genotypes, (ii) a pyramiding strategy where the host carries a double-resistant genotype, (iii) a combining strategy where the host population is a mix of a single-resistant genotype and a double-resistant genotype. First, we use evolutionary epidemiology theory to clarify the interplay between demographic stochasticity and evolutionary dynamics to show that the pyramiding strategy always yields lower probability of evolutionary emergence. Second, we test experimentally these predictions with the introduction of bacteriophages into bacterial populations where we manipulated the diversity and the depth of immunity using a Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated (CRISPR-Cas) system. These biological assays confirm that pyramiding multiple defences into the same host genotype and avoiding combination with single-defence genotypes is a robust way to reduce pathogen evolutionary emergence. The experimental validation of these theoretical recommendations has practical implications in various areas, including for the optimal deployment of resistance varieties in agriculture and for the design of durable vaccination strategies.
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Bacteriófagos , Enfermedades Transmisibles , Humanos , Bacterias/genética , Mutación , Sistemas CRISPR-CasRESUMEN
Sclerotinia sclerotiorum causes white mold (also called stem rot, Sclerotinia blight, etc.) in many economically important plants. It is a notorious soilborne fungal pathogen due to its wide host range and ability to survive in soil for long periods of time as sclerotia. Although host-induced gene silencing (HIGS) was recently demonstrated to be an effective method for controlling white mold, limited gene targets are available. Here, using a forward genetics approach, we identified a RAS-GTPase activating protein, SsGAP1, which plays essential roles in sclerotia formation, compound appressoria production and virulence. In parallel, as revealed by our knockout analysis, the SsGAP1 ortholog in Botrytis cinerea, BcGAP1, plays similar roles in fungal development and virulence. By knocking down SsRAS1 and SsRAS2, we also revealed that both SsRAS1 and SsRAS2 are required for vegetative growth, sclerotia development, compound appressoria production and virulence in S. sclerotiorum. Due to the major roles these RAS signalling components play in Sclerotiniaceae biology, they can be used as HIGS targets to control diseases caused by both S. sclerotiorum and B. cinerea. Indeed, when we introduced HIGS constructs targeting SsGAP1, SsRAS1 and SsRAS2 in Nicotiana benthamiana and Arabidopsis thaliana, we observed reduced virulence. Taken together, our forward genetics gene discovery pipeline in S. sclerotiorum is highly effective in identifying novel HIGS targets to control S. sclerotiorum and B. cinerea.
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Arabidopsis , Ascomicetos , Micosis , Botrytis , Arabidopsis/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiologíaRESUMEN
Upon the emergence of SARS-CoV-2 in the human population, it was conjectured that for this coronavirus the dynamic intra-host heterogeneity typical of RNA viruses would be toned down. Nothing of this sort is observed. Here we review the main observations on the complexity and diverse composition of SARS-CoV-2 mutant spectra sampled from infected patients, within the framework of quasispecies dynamics. The analyses suggest that the information provided by myriads of genomic sequences within infected individuals may have a predictive value of the genomic sequences that acquire epidemiological relevance. Possibilities to reconcile the presence of broad mutant spectra in the large RNA coronavirus genome with its encoding a 3' to 5' exonuclease proofreading-repair activity are considered. Indeterminations in the behavior of individual viral genomes provide a benefit for the survival of the ensemble. We propose that this concept falls in the domain of "stochastic thinking," a notion that applies also to cellular processes, as a means for biological systems to face unexpected needs.
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COVID-19 , Virus ARN , SARS-CoV-2 , Humanos , COVID-19/virología , Genoma Viral , Cuasiespecies , Virus ARN/genética , SARS-CoV-2/genética , SARS-CoV-2/fisiologíaRESUMEN
This study aims to assess the safety, virological, and clinical outcomes of convalescent plasma transfusion (CPT) in immunocompromised patients hospitalized for coronavirus disease 2019 (COVID-19). We conducted a retrospective multicenter cohort study that included all immunosuppressed patients with COVID-19 and RNAemia from May 2020 to March 2023 treated with CPT. We included 81 patients with hematological malignancies (HM), transplants, or autoimmune diseases (69% treated with anti-CD20). Sixty patients (74%) were vaccinated, and 14 had pre-CPT serology >264 BAU/mL. The median delay between symptom onset and CPT was 23 days [13-31]. At D7 post-CPT, plasma PCR was negative in 43/64 patients (67.2%), and serology became positive in 25/30 patients (82%). Post-CPT positive serology was associated with RNAemia negativity (p < 0.001). The overall mortality rate at D28 was 26%, being higher in patients with non-B-cell HM (62%) than with B-cell HM (25%) or with no HM (11%) (p = 0.02). Patients receiving anti-CD20 without chemotherapy had the lowest mortality rate (8%). Positive RNAemia at D7 was associated with mortality at D28 in univariate analysis (HR: 3.05 [1.14-8.19]). Eight patients had adverse events, two of which were severe but transient. Our findings suggest that CPT can abolish RNAemia and ameliorate the clinical course in immunocompromised patients with COVID-19.
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COVID-19 , Neoplasias Hematológicas , Humanos , COVID-19/terapia , Transfusión de Componentes Sanguíneos , Sueroterapia para COVID-19 , Estudios de Cohortes , Plasma , Neoplasias Hematológicas/complicaciones , Neoplasias Hematológicas/terapia , Huésped Inmunocomprometido , ViremiaRESUMEN
INTRODUCTION: Tumor burden is a frequently mentioned parameter; however, a commonly accepted definition is still lacking. METHODS: In this double-center prospective and retrospective study, 76 patients with unresectable stage III or stage IV melanoma treated with ipilimumab were included. We defined the baseline tumor burden (BTB) as the global sum of all metastases' longest diameters before treatment started and correlated the calculated BTB with disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and with the baseline levels of LDH, S100B, and sULPB2. RESULTS: BTB correlated significantly with DCR (p = 0.009), PFS (p = 0.002), OS (p = 0.032), and the occurrence of NRAS mutation (p = 0.006). BTB was also correlated to baseline serum levels of LDH (p = 0.011), S100B (p = 0.027), and SULBP (p < 0.0001). Multivariate analysis revealed that BPB and LDH were independently correlated with PFS and OS. With increasing BTB, disease control was less likely; no patient with a BTB >200 mm achieved disease control. For patients with brain metastasis, no correlation of BTB with DCR (p = 0.251), PFS (p = 0.059), or OS (p = 0.981) was observed. CONCLUSION: Calculated BTB is an independent prognostic factor for patients with metastatic melanoma treated with ipilimumab. Using calculated BTB as a definition of tumor burden may help increase comparability of outcome of therapies in future studies.
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Melanoma , Humanos , Melanoma/tratamiento farmacológico , Melanoma/genética , Melanoma/patología , Ipilimumab/uso terapéutico , Carga Tumoral , Estudios Retrospectivos , Estudios ProspectivosRESUMEN
BACKGROUND: The aim of this study was to investigate the applicability of the central line-associated bloodstream infection (CLABSI) criteria of the Centers for Disease Control and Prevention in pediatric oncology patients. METHODS: Bacteremia episodes from 2020 to 2022 from a prospective cohort of pediatric oncology patients with a central venous catheter were included. Episodes were classified by three medical experts following the CLABSI criteria as either a CLABSI or non-CLABSI (i.e., contamination, other infection source, or mucosal barrier injury-laboratory confirmed bloodstream infection (MBI-LCBI)). Subsequently, they were asked if and why they (dis)agreed with this diagnosis following the criteria. The primary outcome was the percentage of episodes where the experts clinically disagreed with the diagnosis given following the CLABSI criteria. RESULTS: Overall, 84 bacteremia episodes in 71 patients were evaluated. Following the CLABSI criteria, 34 (40%) episodes were classified as CLABSIs and 50 (60%) as non-CLABSIs. In 11 (13%) cases the experts clinically disagreed with the diagnosis following the CLABSI criteria. The discrepancy between the CLABSI criteria and clinical diagnosis was significant; McNemar's test p < .01. Disagreement by the experts with the CLABSI criteria mostly occurred when the experts found an MBI-LCBI a more plausible cause of the bacteremia than a CLABSI due to the presence of a gram negative bacteremia (Pseudomonas aeruginosa n = 3) and/or mucositis. CONCLUSIONS: A discrepancy between the CLABSI criteria and the evaluation of the experts was observed. Adding Pseudomonas aeruginosa as an MBI pathogen and incorporating the presence of mucositis in the MBI-LCBI criteria, might increase the applicability.
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Bacteriemia , Infecciones Relacionadas con Catéteres , Cateterismo Venoso Central , Mucositis , Neoplasias , Sepsis , Niño , Humanos , Infecciones Relacionadas con Catéteres/diagnóstico , Infecciones Relacionadas con Catéteres/etiología , Estudios Prospectivos , Bacteriemia/diagnóstico , Bacteriemia/etiología , Neoplasias/complicaciones , Neoplasias/diagnóstico , Estudios RetrospectivosRESUMEN
In Japan, cerebrovascular diseases and cardiovascular diseases (CVDs) are major causes of death and long-term care. Against this, the Cerebrovascular and Cardiovascular Disease Control Act was passed by a legislative body and promulgated in December 2018, and enacted on December 1, 2019. Based on the Japanese National Plan for Promotion of Measures Against Cerebrovascular and Cardiovascular Disease (Japanese National Plan), prefectural plans have been formulated and published from March 2021 to January 2023. Although the majority of individual measures were comprehensively articulated in accordance with the Japanese National Plan, some prefectures did not describe individual measures such as research, collection of medical information, consultation support for patients with CVD, palliative care, assistance for patients with sequelae, support for maintaining a balance between treatment and work, and measures from childhood and adolescence. Furthermore, a few specific indicators were set for these measures and those related to chronic care. This review identifies the current status of prefectural plans and discusses future challenges and directions.
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Antimicrobial resistance (AMR) remains a critical public health problem that pervades hospitals and health systems worldwide. The ongoing AMR crisis is not only concerning for patient care but also healthcare delivery and quality. This article outlines key components of the origins of AMR in the United States and how it presents across the American healthcare system. Numerous factors contributed to the crisis, including agricultural antibiotic use, wasteful prescribing practices in health care, conflicting behaviours among patients and clinicians, patient demand and satisfaction, and payment and reimbursement models that incentivize inappropriate antibiotic use. To combat AMR, clinicians, healthcare professionals, and legislators must continue to promote and implement innovative solutions, including antibiotic stewardship programmes (ASPs), hand hygiene protocols, ample supply of personal protective equipment (PPE), standardized treatment guidelines for antibiotic prescribing, clinician and patient educational programmes, and health policy initiatives. With the rising prevalence of multi-drug resistant bacterial infections, AMR must become a greater priority to policymakers and healthcare stakeholders.
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Infecciones Bacterianas , Farmacorresistencia Bacteriana , Humanos , Estados Unidos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/epidemiología , Atención a la Salud , HospitalesRESUMEN
Real-time evaluation (RTE) supports populations (e.g., persons experiencing homelessness (PEH) to engage in evaluation of health interventions who may otherwise be overlooked. The aim of this RTE was to explore the understanding of TB amongst PEH, identify barriers/facilitators to attending screening for PEH alongside suggestions for improving TB-screening events targeting PEH, who have high and complex health needs. This RTE composed of free-text structured one-to-one interviews performed immediately after screening at a single tuberculosis (TB) screening event. Handwritten forms were transcribed for thematic analysis, with codes ascribed to answers that were developed into core themes. All RTE participants (n=15) learned about the screening event on the day it was held. Key concerns amongst screening attendees included: stigma around drug use, not understanding the purpose of TB screening, lack of trusted individuals/services present, too many partner organizations involved, and language barriers. Facilitators to screening included a positive welcome to the event, a satisfactory explanation of screening tests, and sharing of results. A need for improved event promotion alongside communication of the purpose of TB screening amongst PEH was also identified. A lack of trust identified by some participants suggests the range of services present should be reconsidered for future screening events.
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Personas con Mala Vivienda , Tamizaje Masivo , Tuberculosis , Humanos , Personas con Mala Vivienda/estadística & datos numéricos , Inglaterra/epidemiología , Tuberculosis/epidemiología , Tuberculosis/diagnóstico , Tuberculosis/prevención & control , Tamizaje Masivo/métodos , Masculino , Femenino , Adulto , Incidencia , Persona de Mediana Edad , Entrevistas como AsuntoRESUMEN
BACKGROUND: The SARS-CoV-2 pandemic underscored the need for pandemic preparedness, with respiratory-transmitted viruses considered as a substantial risk. In pandemics, long-term care facilities (LTCFs) are a high-risk setting with severe outbreaks and burden of disease. Non-pharmacological interventions (NPIs) constitute the primary defence mechanism when pharmacological interventions are not available. However, evidence on the effectiveness of NPIs implemented in LTCFs remains unclear. METHODS: We conducted a systematic review assessing the effectiveness of NPIs implemented in LTCFs to protect residents and staff from viral respiratory pathogens with pandemic potential. We searched Medline, Embase, CINAHL, and two COVID-19 registries in 09/2022. Screening and data extraction was conducted independently by two experienced researchers. We included randomized controlled trials and non-randomized observational studies of intervention effects. Quality appraisal was conducted using ROBINS-I and RoB2. Primary outcomes encompassed number of outbreaks, infections, hospitalizations, and deaths. We synthesized findings narratively, focusing on the direction of effect. Certainty of evidence (CoE) was assessed using GRADE. RESULTS: We analysed 13 observational studies and three (cluster) randomized controlled trials. All studies were conducted in high-income countries, all but three focused on SARS-CoV-2 with the rest focusing on influenza or upper-respiratory tract infections. The evidence indicates that a combination of different measures and hand hygiene interventions can be effective in protecting residents and staff from infection-related outcomes (moderate CoE). Self-confinement of staff with residents, compartmentalization of staff in the LTCF, and the routine testing of residents and/or staff in LTCFs, among others, may be effective (low CoE). Other measures, such as restricting shared spaces, serving meals in room, cohorting infected and non-infected residents may be effective (very low CoE). An evidence gap map highlights the lack of evidence on important interventions, encompassing visiting restrictions, pre-entry testing, and air filtration systems. CONCLUSIONS: Although CoE of interventions was low or very low for most outcomes, the implementation of NPIs identified as potentially effective in this review often constitutes the sole viable option, particularly prior to the availability of vaccinations. Our evidence-gap map underscores the imperative for further research on several interventions. These gaps need to be addressed to prepare LTCFs for future pandemics. TRIAL REGISTRATION: CRD42022344149.
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COVID-19 , Cuidados a Largo Plazo , Infecciones del Sistema Respiratorio , SARS-CoV-2 , Humanos , COVID-19/prevención & control , COVID-19/epidemiología , Infecciones del Sistema Respiratorio/prevención & control , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/virología , Pandemias/prevención & control , Control de Infecciones/métodos , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
BACKGROUND: The first outbreak of African Swine Fever (ASF) in Sweden was detected in 2023 in wild boar. This study was conducted before the first ASF outbreak with the objective of investigating Swedish hunters' perceptions and practices pertaining to ASF ahead of any potential future outbreak. A mixed-methods interview study with Swedish wild boar hunters, consisting of focus group discussions and a questionnaire, was undertaken between October 2020 and December 2021. Six focus groups were conducted online, and an online questionnaire with questions related to practices and habits concerning hunting, the use of bait and hunting trips was sent to all members of the Swedish Hunting and Wildlife Association. A total of 3244 responses were received. RESULTS: Three general themes were identified in a thematic analysis of the data from the focus groups: hunters are willing to engage in ASF prevention and control, simplicity and feasibility are crucial for the implementation of reporting, sampling and control measures, and more information and the greater involvement of the authorities are required in ASF prevention and control. Results from the questionnaire showed that the use of bait was common. Products of animal origin were rarely used for baiting; the most common product used was maize. Hunting trips abroad, especially outside of the Nordic countries, were uncommon. CONCLUSIONS: Hunting tourism and the use of bait do not seem to constitute a major risk for the introduction of ASF to wild boar populations in Sweden. The accessibility of relevant information for each concerned stakeholder and the ease of reporting and sampling are crucial to maintain the positive engagement of hunters.
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Fiebre Porcina Africana , Brotes de Enfermedades , Sus scrofa , Animales , Fiebre Porcina Africana/epidemiología , Suecia/epidemiología , Brotes de Enfermedades/veterinaria , Humanos , Porcinos , Masculino , Encuestas y Cuestionarios , Femenino , Conocimientos, Actitudes y Práctica en Salud , Grupos Focales , Persona de Mediana Edad , AdultoRESUMEN
Dollar spot is a destructive foliar disease of amenity turfgrass caused by the fungus Clarireedia spp., and mainly Clarireedia jacksonii on the northern US region's cool-season grass. Oxalic acid (OA) is an important pathogenicity factor in related fungal plant pathogens such as Sclerotinia sclerotiorum, however, the role of OA in the pathogenic development of C. jacksonii remains unclear due to its recalcitrance to genetic manipulation. To overcome these challenges, a CRISPR/Cas9-mediated homologous recombination approach was developed. Using this novel approach, the oxaloacetate acetylhydrolase (Oah) gene that is required for the biosynthesis of OA was deleted from C. jacksonii wild-type stain. Two independent knockout mutants, ΔCjoah-1 and ΔCjoah-2, were generated and inoculated on potted creeping bentgrass along with a wild-type isolate (WT) and a genome sequenced isolate LWC-10. After 12 days, bentgrass inoculated with the mutants ΔCjoah-1 and ΔCjoah-2 exhibited 59.41% lower dollar spot severity compared to the WT and LWC-10 isolates. Oxalic acid production and environmental acidification were significantly reduced in both mutants when compared to the WT and LWC-10. Surprisingly, stromal formation was also severely undermined in the mutants in vitro, suggesting a critical developmental role of OA independent of plant infection. These results demonstrate that OA plays a significant role in C. jacksonii virulence and provide novel directions for future management of dollar spot.
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Mixtures of fungicides with different modes of action are commonly used as disease and resistance management tools, but little is known of mixtures of natural and synthetic products. In this study, mixtures of metabolites from the rhizobacterium Pseudomonas chlororaphis strain ASF009 formulated as Howler EVO with below-label rates (50 µg/ml) of conventional sterol demethylation inhibitor (DMI) fungicides were investigated for control of anthracnose of cherry (Prunus avium) caused by Colletotrichum siamense. Howler mixed with metconazole or propiconazole synergistically reduced disease severity through lesion growth. Real-time PCR showed that difenoconazole, flutriafol, metconazole, and propiconazole induced the expression of DMI target genes CsCYP51A and CsCYP51B in C. siamense. The addition of Howler completely suppressed the DMI fungicide-induced expression of both CYP51 genes. We hypothesize that the downregulation of DMI fungicide-induced expression of the DMI target genes may, at least in part, explain the synergism observed in detached fruit assays.
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Biological control agent Bacillus subtilis formulated as Theia is registered for control of fungal and bacterial diseases of fruit crops. Combinations of Theia and strategic concentrations of two demethylation inhibitor (DMI) fungicides were investigated to explore potential synergisms. Bacteria were cultured in nutrient broth and combined with technical grades and two formulations of propiconazole (emulsifiable concentrate [EC] and wettable powder) and metconazole (EC and water-dispersible granule) at 0, 10, 50, 100, and 150 µg/ml of active ingredient. After cocultivation, the optical density (OD600) and colony forming units (CFU/ml) were evaluated. In contrast to EC formulations, the wettable powder or water-dispersible granule formulations at 10 or 50 µg/ml of both DMIs did not affect vegetative cell growth. The mixture of Theia and each formulated DMI at 50 µg/ml of active ingredient resulted in a significant reduction of Monilinia fructicola lesion development on apple, Colletotrichum siamense lesion development on cherry, and Botrytis cinerea lesion development on cherry. The combination of Theia with EC formulations showed weaker disease reduction due to antagonism. Only Theia plus non-EC formulated propiconazole and metconazole significantly reduced brown rot disease incidence of apple compared with the respective solo treatments and anthracnose disease incidence of cherry compared with the untreated control. Our results indicated that at least some DMI fungicides possess bactericidal effects depending on the formulation and concentration. The combination of Theia with a lower-than-label-rate concentration (50 µg/ml) of the DMI fungicides propiconazole and metconazole showed potential for synergistic effects, especially when non-EC formulations were used.
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Bacillus subtilis , Botrytis , Frutas , Fungicidas Industriales , Enfermedades de las Plantas , Triazoles , Fungicidas Industriales/farmacología , Bacillus subtilis/efectos de los fármacos , Triazoles/farmacología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Botrytis/efectos de los fármacos , Frutas/microbiología , Productos Agrícolas/microbiología , Colletotrichum/efectos de los fármacos , Colletotrichum/crecimiento & desarrollo , Ascomicetos/efectos de los fármacos , Ascomicetos/fisiología , Ascomicetos/crecimiento & desarrolloRESUMEN
Xylella fastidiosa (Xf) is a quarantine plant pathogen capable of colonizing the xylem of a wide range of hosts. Currently, there is no cure able to eliminate the pathogen from a diseased plant, but several integrated strategies have been implemented for containing the spread of Xf. Nanotechnology represents an innovative strategy based on the possibility of maximizing the potential antibacterial activity by increasing the surface-to-volume ratio of nanoscale formulations. Nanoparticles based on chitosan and/or fosetyl-Al have shown different in vitro antibacterial efficacy against Xf subsp. fastidiosa (Xff) and pauca (Xfp). This work demonstrated the uptake of chitosan-coated fosetyl-Al nanocrystals (CH-nanoFos) by roots and their localization in the stems and leaves of Olea europaea plants. Additionally, the antibacterial activity of fosetyl-Al, nano-fosetyl, nano-chitosan, and CH-nanoFos was tested on Nicotiana tabacum cultivar SR1 (Petite Havana) inoculated with Xff, Xfp, or Xf subsp. multiplex (Xfm). The bacterial load was evaluated with qPCR, and the results showed that CH-nanoFos was the only treatment able to reduce the colonization of Xff, Xfm, and Xfp in tobacco plants. Additionally, the area under the disease progress curve, used to assess symptom development in tobacco plants inoculated with Xff, Xfm, and Xfp and treated with CH-nanoFos, showed a reduction in symptom development. Furthermore, the twitching assay and bacterial growth under microfluidic conditions confirmed the antibacterial activity of CH-nanoFos.
Asunto(s)
Quitosano , Nanopartículas , Nicotiana , Enfermedades de las Plantas , Xylella , Xylella/fisiología , Xylella/efectos de los fármacos , Quitosano/farmacología , Quitosano/química , Nicotiana/microbiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Nanopartículas/química , Antibacterianos/farmacología , Antibacterianos/química , Hojas de la Planta/microbiología , Raíces de Plantas/microbiología , Olea/microbiologíaRESUMEN
Timely and accurate identification of peanut pests and diseases, coupled with effective countermeasures, are pivotal for ensuring high-quality and efficient peanut production. Despite the prevalence of pests and diseases in peanut cultivation, challenges such as minute disease spots, the elusive nature of pests, and intricate environmental conditions often lead to diminished identification accuracy and efficiency. Moreover, continuous monitoring of peanut health in real-world agricultural settings demands solutions that are computationally efficient. Traditional deep learning models often require substantial computational resources, limiting their practical applicability. In response to these challenges, we introduce LSCDNet (Lightweight Sandglass and Coordinate Attention Network), a streamlined model derived from DenseNet. LSCDNet preserves only the transition layers to reduce feature map dimensionality, simplifying the model's complexity. The inclusion of a sandglass block bolsters features extraction capabilities, mitigating potential information loss due to dimensionality reduction. Additionally, the incorporation of coordinate attention addresses issues related to positional information loss during feature extraction. Experimental results showcase that LSCDNet achieved impressive metrics with an accuracy, precision, recall, and F1 score of 96.67%, 98.05%, 95.56%, and 96.79%, respectively, while maintaining a compact parameter count of merely 0.59M. When compared to established models such as MobileNetV1, MobileNetV2, NASNetMobile, DenseNet-121, InceptionV3, and Xception, LSCDNet outperformed with accuracy gains of 2.65%, 4.87%, 8.71%, 5.04%, 6.32%, and 8.2% respectively, accompanied by substantially fewer parameters. Lastly, we deployed the LSCDNet model on Raspberry Pi for practical testing and application, achieving an average recognition accuracy of 85.36%, thereby meeting real-world operational requirements.