Epidemiology and control strategies applied to ash dieback and chestnut ink disease

Main goal of forest diseases’ management is to reduce economic, biological and aesthetic damages and biodiversity loss caused by plant parasites. The many strategies used can be grouped under two main actions, prevention (prophylaxis in some early writings) and therapy (treatment or cure). Prevention is limited primarily by the lack of knowledge of the organisms involved, including host plants. Mathematical models have been used to extend the understanding of plant disease epidemiology on a number of fronts, providing an opportunity for a more rational use of resources on expensive field trials and representing a step towards more sustainable control measures. From a curative point of view, current efforts by scientists have focused on developing diseases management (Pest Management = PM) concepts in order to balance the benefits of pesticides with the ecological concerns of their residues contaminating the environment. In this thesis, the two PM principles were applied from an innovative point of view on two case studies: ash dieback caused by Hymenoscyphus fraxineus, which can be considered the most serious disease for Fraxinus genus in Europe, and chestnut ink disease, caused by Phytophthora cambivora and P. cinnamomi. In the first part of the thesis, the two diseases are introduced, in order to permit the evaluation of similarities and differences (chapter I). Subsequently, from chapter II to chapter V, the experimental trials performed are described. In particular, in chapter II a study of the ecological niche of H. fraxineus, with the characterization of the environmental variables associated with naturally infected zones, is reported. This procedure was realized with Species Distribution Models (SDM), widely utilized in the ecological field and only recently applied to plant pathology. The presence of the pathogen was highly correlated to three summer predictors: abundant precipitation, high soil moisture and low air temperature, in comparison with the averages of the study area. The ensemble forecasting technique was then applied to obtain a prediction of the potential distribution of the pathogen at European scale, considering the distribution maps of Fraxinus excelsior and Fraxinus angustifolia, susceptible to the parasite. At last, an innovative method of network analysis permitted to identify the suitable areas that are not reachable by the pathogen with a natural spread. Chapter III reports a study conducted to evaluate six fungicides for their potential to control ash dieback. Initially, in vitro tests of the active ingredients against five different strains of the pathogen indicated thiabendazole, propiconazole and allicin as the most effective fungicides, with lower median lethal doses than procloraz. In contrast, copper sulphate and potassium phosphite were totally ineffective. Subsequently, the antifungal activities of the best three compounds were investigated in planta against H. fraxineus by trunk injection on European ashes inoculated with an indigenous strain. The test was preceded by preliminary trials to maximize the efficacy of injections; in the experimental conditions highest speed was reached with the addition of 1.2 % acetic acid to the aqueous solution and making treatments in early morning or late afternoon. Considering the results of in planta trial, thiabendazole and allicin significantly slowed down the growth of the necroses in the growing season, in contrast propiconazole injections were impracticable. The studies in chapters IV and V recall the methodologies applied to ash dieback, with application to chestnut ink disease complex. In particular, in chapter IV fuzzy logic theory was applied considering the environmental variables, such as minimum winter temperature, summer drought, slope's aspect, streams' distance and soil's permeability, that mainly can influence the development of the disease. The model was validated with a broad field survey conducted in a chestnut area in Treviso province. Moreover, uncertainty maps (regarding model structure, inputs and parameters) were produced for the correct interpretation of the prediction. Great part of the chestnut area in the study zone resulted as suitable for the development of ink disease, whereas only the 18.8 %, corresponding to higher elevation zones, presented inferior risks. In a second study (chapter V), a comparative efficacy trial on four potassium phosphite formulations by means of endotherapy against chestnut ink disease is performed. P. cinnamomi was isolated with baiting technique from symptomatic chestnuts and was inoculated on 50 asymptomatic trees. As a result of endotherapic treatments, the unique solution that significantly slowed down necroses' growth was potassium phosphite (35 %) with an addition of 0.1 % micronutrient solution. An additional endotherapic trial was conducted in a preliminary way in the chestnut where P. cinnamomi was isolated, with the main aim to evaluate growth stimulation of active growing callus next to the shape flame necroses by the injected solution of potassium phosphite 70 %. In this case, results did not highlight a significant difference between treated trees and water control ones, probably for the need of longer times for older trees. On the base of the achieved results, epidemiological modelling and endotherapic treatments, applied both to ash dieback and chestnut ink disease, can represent fundamental tools in the management of these important diseases and should be applied in an Integrated Pest Management (IPM) approach, together with appropriate cultural techniques to maximize benefits

SOCIAL AND CLINICAL DETERMINANTS OF COMPULSORY AND VOLUNTARY ADMISSIONS WITHIN THE FRAMEWORK OF AN ITALIAN COMMUNITY MENTAL HEALTH SYSTEM

Social and clinical determinants of 30 compulsory admissions (CAs) to a psychiatric ward during a six-month period were compared to 134 voluntary admissions (VAs), and outcomes of hospitalisation were assessed in relation to its types. Psychosocial and clinical characteristics at admission and discharge were measured using 5 scales. Unemployment, hospitalisations >7 days and continuing hospitalisation in Community Mental Health Centres were positively associated with CA. At admission, CAs showed lower functioning, while outcome at discharge was similar. Social determinants had a main role in determining CAs. Clinical and psychosocial outcomes might have been improved by a mental health system community-based

Varicella seroepidemiology and immunization in a cohort of future healthcare workers in the pre-vaccination era

Objectives: The goal of this study was to establish the seroprevalence of positive antibodies against varicella and compliance with varicella vaccination in the pre-vaccination era. Methods: A cohort of 10 683 Italian students from Padua University Medical School (from 2004 to 2019) were enrolled and classified as unvaccinated, vaccinated once, or vaccinated twice against varicella, according to their vaccination certificate. The antibody titre was measured and the seroprevalence of positive subjects was determined. Subjects with negative or equivocal antibodies were invited for vaccination, and then the antibody titre was retested. Results: Unvaccinated students were mostly seropositive (95.6%), compared with vaccinated students who were less seropositive (68.0% after one dose and 78.6% after two doses) and had significantly lower antibody titres (p < 0.0001). The post-test vaccination had a positive response rate of 85.4%: 67.4% after one dose and 91.4% after two doses. Conclusions: In the pre-vaccination era, only 3.3% of future healthcare workers were vaccinated against varicella (1.1% once and 2.2% twice). Vaccination or revaccination of negative and equivocal individuals could reduce the number of susceptible people. Implementation of varicella vaccine (two doses) in healthcare workers is of primary importance to reduce the risk of transmission

Are patients improving during and after a psychiatric hospitalisation? Continuity of care outcomes of compulsory and voluntary admissions to an Italian psychiatric ward

Background: To compare the characteristics of compulsory admissions (CAs) and voluntary admissions (VAs) in a General Hospital Psychiatric Unit (GHPU), and to assess whether CA and VA patients' outcomes improved during hospitalisation and follow-up in mental health services (MHS) based on community continuity of care. Design and method: Observational longitudinal study comparing 19 CAs and 83 VAs consecutively admitted to GHPU of Udine, Italy, and followed up for six months by MHS. Five psychometric scales assessed psychosocial and clinical characteristics for each patient at admission (T0), discharge (T1) and follow-up (T2). Statistical analyses were performed using: multivariate logistic regression for comparing CA and VA; Friedman \u3c72 and Mann-Whitney tests for outcomes' improvement. Results: Being hospitalised for a psychotic crisis was the most significant predictor of CA (OR = 5.07). An outcomes' improvement was observed from T0 to T1 in almost all psychometric tests, while from T1 to T2 only for PSP-A (useful social activities), CGI-S (severity of illness) and CGI-EI (drug's efficacy related to side effects). CA was associated to lower performances in all scales at T0, in GAF and CGI-S at T1, while no difference with VA was observed at T2. Conclusion: CA and VA patients improved to a same extent during hospitalisation and follow-up, particularly in relation to social functioning. This fosters the hypothesis that community-based MHS using a longitudinal continuity of care model might achieve recovery in a long-term perspective. Future research may benefit by considering patients' subjective experiences and assessing long-term improvement in those who received person-centred interventions

Will We Have a Cohort of Healthcare Workers Full Vaccinated against Measles, Mumps, and Rubella?

Healthcare workers are a population exposed to several infectious diseases, and an immunization programme is essential for the maintenance of good vaccination coverage to protect workers and patients. A population of 10,653 students attending degree courses at Padua Medical School (medicine and surgery, dentistry and health professions) was screened for vaccination coverage and antibody titres against rubella, mumps, and measles. The students were subdivided into five age classes according to their date of birth: those born before 1980, between 1980 and 1985, between 1986 and 1990, between 1991 and 1995, and after 1995. Vaccination coverage was very low in students born before 1980, but the rate of positive antibody titre was high due to infection in infancy. Increasing date of birth showed increased vaccination coverage. In contrast, immune coverage was high for rubella (more than 90%) but not for mumps and measles (approximately 80%). An "anomaly" was observed for mumps and measles in the cohort born between 1991 and 1995, probably due to the trivalent vaccine formulation. Students born after 1990 showed vaccination coverage that exceeded 90%. It is therefore very likely that we will have a future generation of healthcare workers with optimal vaccination coverage

Therapeutic Effect of Palmitoylethanolamide in Cognitive Decline: A Systematic Review and Preliminary Meta-Analysis of Preclinical and Clinical Evidence

Cognitive decline is believed to be associated with neurodegenerative processes involving excitotoxicity, oxidative damage, inflammation, and microvascular and blood-brain barrier dysfunction. Interestingly, research evidence suggests upregulated synthesis of lipid signaling molecules as an endogenous attempt to contrast such neurodegeneration-related pathophysiological mechanisms, restore homeostatic balance, and prevent further damage. Among these naturally occurring molecules, palmitoylethanolamide (PEA) has been independently associated with neuroprotective and anti-inflammatory properties, raising interest into the possibility that its supplementation might represent a novel therapeutic approach in supporting the body-own regulation of many pathophysiological processes potentially contributing to neurocognitive disorders. Here, we systematically reviewed all human and animal studies examining PEA and its biobehavioral correlates in neurocognitive disorders, finding 33 eligible outputs. Studies conducted in animal models of neurodegeneration indicate that PEA improves neurobehavioral functions, including memory and learning, by reducing oxidative stress and pro-inflammatory and astrocyte marker expression as well as rebalancing glutamatergic transmission. PEA was found to promote neurogenesis, especially in the hippocampus, neuronal viability and survival, and microtubule-associated protein 2 and brain-derived neurotrophic factor expression, while inhibiting mast cell infiltration/degranulation and astrocyte activation. It also demonstrated to mitigate β-amyloid-induced astrogliosis, by modulating lipid peroxidation, protein nytrosylation, inducible nitric oxide synthase induction, reactive oxygen species production, caspase3 activation, amyloidogenesis, and tau protein hyperphosphorylation. Such eects were related to PEA ability to indirectly activate cannabinoid receptors and modulate proliferator-activated receptor-α (PPAR-α) activity. Importantly, preclinical evidence suggests that PEA may act as a disease-modifying-drug in the early stage of a neurocognitive disorder, while its protective effect in the frank disorder may be less relevant. Limited human research suggests that PEA supplementation reduces fatigue and cognitive impairment, the latter being also meta-analytically confirmed in 3 eligible studies. PEA improved global executive function, working memory, language deficits, daily living activities, possibly by modulating cortical oscillatory activity and GABAergic transmission. There is currently no established cure for neurocognitive disorders but only treatments to temporarily reduce symptom severity. In the search for compounds able to protect against the pathophysiological mechanisms leading to neurocognitive disorders, PEA may represent a valid therapeutic option to prevent neurodegeneration and support endogenous repair processes against disease progression

The potential for pesticide trunk injections for control of thousand cankers disease of walnut

Thousand cankers disease, caused by the pathogen Geosmithia morbida vectored by the bark beetle Pityophthorus juglandis, has emerged as an important disease of walnut trees in Europe. The present study was performed to evaluate the efficacy of trunk injections of four commercial fungicides and one insecticide for control of the fungus and its vector. Laboratory tests indicated that fungicides containing prochloraz + tetraconazole were the most effective. Field trials on non-infected trees allowed for the selection of a mixture containing prochloraz and tetraconazole (Binal Pro), the insecticide abamectin (Vertimec EC) and the adjuvant 2-(2-ethoxyethoxy) ethanol (CarbitolTM) as having rapid host uptake. Injections of this formulation in naturally infected black walnut trees reduced the presence of G. morbida, supporting trunk injection as an efficient and low impact technique to manage fungal damage on infected trees

Ultrastructural modifications in Common ash tissues colonised by Chalara fraxinea

Chalara fraxinea, the cause of ash dieback, is present in many European countries and constitutes a severe threat to Fraxinus spp. in forests, urban areas and nurseries. This study investigated tissue colonisation strategies of the parasite in Common ash at ultrastructural level and demonstrated that C. fraxinea develops intracellularly, moving through the cells and easily colonising the phloem, paratracheal parenchyma and parenchymatic rays. However, damage to either the plasmalemma or cell walls was not observed under our experimental conditions. Furthermore, the presence of intrahyphal hyphae was frequently detected, which are likely associated with a regeneration mechanism

Epidemiology and control strategies applied to ash dieback and chestnut ink disease

Main goal of forest diseases’ management is to reduce economic, biological and aesthetic damages and biodiversity loss caused by plant parasites. The many strategies used can be grouped under two main actions, prevention (prophylaxis in some early writings) and therapy (treatment or cure). Prevention is limited primarily by the lack of knowledge of the organisms involved, including host plants. Mathematical models have been used to extend the understanding of plant disease epidemiology on a number of fronts, providing an opportunity for a more rational use of resources on expensive field trials and representing a step towards more sustainable control measures. From a curative point of view, current efforts by scientists have focused on developing diseases management (Pest Management = PM) concepts in order to balance the benefits of pesticides with the ecological concerns of their residues contaminating the environment. In this thesis, the two PM principles were applied from an innovative point of view on two case studies: ash dieback caused by Hymenoscyphus fraxineus, which can be considered the most serious disease for Fraxinus genus in Europe, and chestnut ink disease, caused by Phytophthora cambivora and P. cinnamomi. In the first part of the thesis, the two diseases are introduced, in order to permit the evaluation of similarities and differences (chapter I). Subsequently, from chapter II to chapter V, the experimental trials performed are described. In particular, in chapter II a study of the ecological niche of H. fraxineus, with the characterization of the environmental variables associated with naturally infected zones, is reported. This procedure was realized with Species Distribution Models (SDM), widely utilized in the ecological field and only recently applied to plant pathology. The presence of the pathogen was highly correlated to three summer predictors: abundant precipitation, high soil moisture and low air temperature, in comparison with the averages of the study area. The ensemble forecasting technique was then applied to obtain a prediction of the potential distribution of the pathogen at European scale, considering the distribution maps of Fraxinus excelsior and Fraxinus angustifolia, susceptible to the parasite. At last, an innovative method of network analysis permitted to identify the suitable areas that are not reachable by the pathogen with a natural spread. Chapter III reports a study conducted to evaluate six fungicides for their potential to control ash dieback. Initially, in vitro tests of the active ingredients against five different strains of the pathogen indicated thiabendazole, propiconazole and allicin as the most effective fungicides, with lower median lethal doses than procloraz. In contrast, copper sulphate and potassium phosphite were totally ineffective. Subsequently, the antifungal activities of the best three compounds were investigated in planta against H. fraxineus by trunk injection on European ashes inoculated with an indigenous strain. The test was preceded by preliminary trials to maximize the efficacy of injections; in the experimental conditions highest speed was reached with the addition of 1.2 % acetic acid to the aqueous solution and making treatments in early morning or late afternoon. Considering the results of in planta trial, thiabendazole and allicin significantly slowed down the growth of the necroses in the growing season, in contrast propiconazole injections were impracticable. The studies in chapters IV and V recall the methodologies applied to ash dieback, with application to chestnut ink disease complex. In particular, in chapter IV fuzzy logic theory was applied considering the environmental variables, such as minimum winter temperature, summer drought, slope's aspect, streams' distance and soil's permeability, that mainly can influence the development of the disease. The model was validated with a broad field survey conducted in a chestnut area in Treviso province. Moreover, uncertainty maps (regarding model structure, inputs and parameters) were produced for the correct interpretation of the prediction. Great part of the chestnut area in the study zone resulted as suitable for the development of ink disease, whereas only the 18.8 %, corresponding to higher elevation zones, presented inferior risks. In a second study (chapter V), a comparative efficacy trial on four potassium phosphite formulations by means of endotherapy against chestnut ink disease is performed. P. cinnamomi was isolated with baiting technique from symptomatic chestnuts and was inoculated on 50 asymptomatic trees. As a result of endotherapic treatments, the unique solution that significantly slowed down necroses' growth was potassium phosphite (35 %) with an addition of 0.1 % micronutrient solution. An additional endotherapic trial was conducted in a preliminary way in the chestnut where P. cinnamomi was isolated, with the main aim to evaluate growth stimulation of active growing callus next to the shape flame necroses by the injected solution of potassium phosphite 70 %. In this case, results did not highlight a significant difference between treated trees and water control ones, probably for the need of longer times for older trees. On the base of the achieved results, epidemiological modelling and endotherapic treatments, applied both to ash dieback and chestnut ink disease, can represent fundamental tools in the management of these important diseases and should be applied in an Integrated Pest Management (IPM) approach, together with appropriate cultural techniques to maximize benefits.Lo scopo principale della gestione delle malattie forestali è la riduzione dei danni economici, biologici ed estetici e delle perdite di biodiversità dovute alle malattie delle piante. Le molteplici strategie usate nella gestione delle malattie possono essere raggruppate in due azioni principali, la prevenzione (anche detta profilassi) e la terapia (trattamento o cura). La prevenzione è principalmente limitata dalla mancanza di conoscenza in merito all'organismo in oggetto e i suoi ospiti. I modelli matematici sono stati utilizzati per approfondire la conoscenza delle malattie delle piante con vari obiettivi. Essi offrono l'opportunità di affrontare un uso razionale delle risorse riguardo ai costosi monitoraggi e rappresentano un passo fondamentale verso misure di controllo più sostenibili. Da un punto di vista curativo, oggigiorno gli sforzi sono focalizzati allo sviluppo di concetti di gestione delle malattie che bilancino i benefici dei pesticidi con le preoccupazioni in merito ai residui che possono contaminare l'ambiente. In questa tesi, i due principi della gestione della malattia sono stati affrontati con due casi studio: il dissecamento del frassino, causata da Hymenoscyphus fraxineus, che può essere considerata la più grave malattia del genere Fraxinus in Europa, e il mal dell'inchiostro del castagno, causata da Phytophthora cambivora (Petri) Buism. and P. cinnamomi Rands. Nella prima parte della tesi sono state introdotte le due malattie, in modo da poterne appurare somiglianze e differenze (Capitolo I). Successivamente, dal capitolo II al capitolo V sono descritte le prove sperimentali effettuate. In particolare, nel capitolo II è stato approntato uno studio della nicchia ecologica di H. fraxineus, con la caratterizzazione di variabili ecologiche e ambientali associate a zone naturalmente infette. Tale procedura è stata effettuata tramite Species Distribution Models (SDM), ampiamente utilizzati in ambito ecologico e da poco tempo anche nell'ambito della patologia vegetale. La presenza del patogeno è risultata fortemente correlata a tre variabili ambientali estive, in particolare abbondanti precipitazioni, alta umidità del suolo e basse temperature, in comparazione con la media dell'area di studio. Successivamente la tecnica dell'ensemble forecasting è stata applicata per ottenere una predizione della distribuzione potenziale del patogeno a scala europea, considerando la distribuzione di F. excelsior e F. angustifolia, ospiti della malattia. Infine, un innovativo metodo di network analysis ha permesso di individuare le aree ecologicamente adatte al patogeno ma non raggiungibili con una diffusione naturale. Nel capitolo III viene descritto uno studio condotto per valutare sei diversi fungicidi contro H. fraxineus. Inizialmente è stata effettuata una prova in vitro dei prodotti commerciali contro cinque ceppi del patogeno. Tiabendazolo, propiconazolo e allicina sono risultati i fungicidi più efficaci, con dose letale mediana più bassa, rispetto, per esempio, al principio attivo procloraz. Al contrario, il solfato di rame e i fosfiti di potassio si sono rilevati completamente inefficaci. Successivamente, i tre migliori fungicidi sono stati applicati in planta tramite trattamenti endoterapici su frassini maggiori inoculati al tronco con un ceppo autoctono. Tale test è stato anticipato da prove preliminari per massimizzare l'efficienza delle iniezioni; nelle condizioni stazionali e climatiche delle prove, maggiori velocità sono state raggiunte con soluzione acquosa addizionata con 1.2 % di acido acetico, effettuando i trattamenti la mattina presto o nel pomeriggio tardo. Considerando i risultati della prova in planta, tiabendazolo e allicina hanno rallentato in maniera significativa la crescita delle necrosi, al contrario non si è riusciti a iniettare la soluzione a base di propiconazolo. I capitoli IV e V riprendono le metodologie applicate contro la patologia del dissecamento del frassino, applicandole al mal dell'inchiostro del castagno. In particolare nel capitolo IV, la teoria fuzzy è stata adottata nello studio del complesso del mal dell'inchiostro, includendo nella costruzione del modello variabili ambientali quali temperatura minima invernale, siccità estiva, esposizione, distanza da corsi d'acqua e permeabilità del suolo, che più possono influire sullo sviluppo della malattia. Il modello è stato validato con un'ampia ricerca sul campo condotta nei castagneti nell'area di Treviso. Inoltre, sono state prodotte delle mappe dell'incertezza (inerenti a struttura, input e parametri del modello) per la corretta interpretazione della previsione. Buona parte dell'area a castagneto nella zona di studio si è rivelata adatta allo sviluppo del mal dell'inchiostro, mentre solo il 18.8 %, corrispondente alle aree più elevate, presentava rischi inferiori. Un secondo studio (capitolo V) ha riguardato una prova comparativa di efficacia di quattro formulazioni di fosfiti di potassio tramite endoterapia. P. cinnamomi è stata isolata con la tecnica del baiting in un castagneto affetto da mal dell'inchiostro ed è stata inoculata su 50 castagni asintomatici. In seguito ai trattamenti endoterapici, l'unica soluzione che ha significativamente rallentato la crescita delle necrosi è stata quella a base di fosfiti di potassio (35 %) addizionata con 0.1 % di soluzione di micronutrienti. Un'ulteriore prova di endoterapia è stata condotta in via preliminare nel castagneto abbandonato in cui era stata isolata P. cinnamomi, al fine di valutare la stimolazione alla crescita del callo cicatriziale da parte della soluzione iniettata fosfiti di potassio 70 %. I risultati ottenuti in questo caso non hanno evidenziato una differenza significativa rispetto ai controlli trattati con acqua, probabilmente per una necessità di tempi più lunghi considerando piante di età maggiore. In base ai risultati raggiunti, la modellistica epidemiologica e i trattamenti endoterapici sperimentati in merito alle patologie del dissecamento del frassino e al mal dell'inchiostro del castagno possono rappresentare degli strumenti fondamentali nella gestione integrata delle malattie considerate, da applicare insieme ad appropriate tecniche colturali per massimizzarne i benefici