Current and future distribution of a parasite with complex life cycle under global change scenarios: Echinococcus multilocularis in Europe

Global change is expected to have complex effects on the distribution and transmission patterns of zoonotic parasites. Modelling habitat suitability for parasites with complex life cycles is essential to further our understanding of how disease systems respond to environmental changes, and to make spatial predictions of their future distributions. However, the limited availability of high quality occurrence data with high spatial resolution often constrains these investigations. Using 449 reliable occurrence records for Echinococcus multilocularis from across Europe published over the last 35 years, we modelled habitat suitability for this parasite, the aetiological agent of alveolar echinococcosis, in order to describe its environmental niche, predict its current and future distribution under three global change scenarios, and quantify the probability of occurrence for each European country. Using a machine learning approach, we developed large-scale (25 × 25 km) species distribution models based on seven sets of predictors, each set representing a distinct biological hypothesis supported by current knowledge of the autecology of the parasite. The best-supported hypothesis included climatic, orographic and land-use/land-cover variables such as the temperature of the coldest quarter, forest cover, urban cover and the precipitation seasonality. Future projections suggested the appearance of highly suitable areas for E. multilocularis towards northern latitudes and in the whole Alpine region under all scenarios, while decreases in habitat suitability were predicted for central Europe. Our spatially explicit predictions of habitat suitability shed light on the complex responses of parasites to ongoing global change

A highly endemic area of Echinococcus multilocularis identified through a comparative re-assessment of prevalence in the red fox (Vulpes vulpes), Alto Adige (Italy: 2019-2020)

Surveillance of Echinococcus multilocularis at the edge of its range is hindered by fragmented distributional patterns and low prevalence in definitive hosts. Thus, tests with adequate levels of sensitivity are especially important for discriminating between infected and non-infected areas. In this study we reassessed the prevalence of E. multilocularis at the southern border of its distribution in Province of Bolzano (Alto Adige, northeastern Alps, Italy), to improve surveillance in wildlife and provide more accurate estimates of exposure risk. We compared the diagnostic test currently implemented for surveillance based on coproscopy and multiplex PCR (CMPCR) to a real-time quantitative PCR (qPCR) in 235 fox faeces collected in 2019 and 2020. The performances of the two tests were estimated using a scraping technique (SFCT) applied to the small intestines of a subsample (n = 123) of the same foxes as the reference standard. True prevalence was calculated and the sample size required by each faecal test for the detection of the parasite was then estimated. True prevalence of E. multilocularis in foxes (14.3%) was markedly higher than reported in the last decade, which was never more than 5% from 2012 to 2018 in the same area. In addition, qPCR showed a much higher sensitivity (83%) compared to CMPCR (21%) and agreement with the reference standard was far higher for qPCR (0.816) than CMPCR (0.298) meaning that for the latter protocol, a smaller sample size would be required to detect the disease. Alto Adige should be considered a highly endemic area. Routine surveillance on definitive hosts at the edges of the E. multilocularis distribution should be applied to smaller geographic areas, and rapid, sensitive diagnostic tools using directly host faeces, such as qPCR, should be adopted

Identification of areas suitable for the sable antelope (Hippotragus niger niger) in South Africa with the use of a Species Distribution Model

L’antilope nera Hippotragus niger (Harris, 1838) – Bovidae - è distribuita in Africa sudorientale, in particolare in Zimbabwe, Botswana, Sudafrica, Mozambico e Malawi. È una delle specie di maggiori dimensioni tra le antilopi africane; è caratterizzata da una peculiare colorazione bruno-nera e da imponenti corna che formano un arco rivolto all’indietro. Hippotragus niger predilige spazi aperti con pochi alberi o arbusti e si ciba di erbe medio-alte soprattutto della famiglia delle Poaceae. Sebbene sia stata classificata come Least Concern dalla IUCN, in Sudafrica, al margine del suo areale di distribuzione, la sua popolazione sta andando incontro a un rapido declino demografico a causa: 1) dei cambiamenti climatici, 2) della caccia e del bracconaggio, 3) della frammentazione, degradazione e perdita dell’habitat e 4) della competizione e predazione. Pertanto, è importante cercare di elaborare dei piani di conservazione per la specie in modo da poter contribuire alla sua salvaguardia. Questo lavoro di tesi mira ad individuare aree di interesse in Sudafrica, che potrebbero essere selezionate per eventuali progetti di introduzione o reintroduzione della specie. Per tale scopo sono state utilizzate delle tecniche di Species Distribution Models (SDMs) al fine di individuare la potenziale distribuzione dell’antilope nera in Sudafrica, sia nel presente che nel futuro, quest’ultimo in base ai cambiamenti climatici in itinere. Gli SDMs sono dei modelli statistici che elaborano la potenziale distribuzione di una specie in una data area stimando il grado di similarità tra le condizioni ambientali delle località in cui la specie è presente e quelle di altre località in cui potrebbe essere potenzialmente immessa. Per elaborare tali modelli sono necessari i dati di presenza della specie e quelli delle variabili abiotiche rilevanti per la sua distribuzione. A tale scopo sono stati utilizzati i record biologici della presenza dell’antilope nera nella forma di coordinate geografiche (latitudine-longitudine) delle località in cui la specie è stata registrata nel territorio sudafricano. Questi dati sono stati forniti dall’Endangered Wildlife Trust, un’organizzazione no profit per la conservazione della natura in Sudafrica. Le variabili abiotiche considerate nello studio sono di due tipi: climatiche, derivate dai valori di temperatura e precipitazioni, e non climatiche (vegetazione presente sul territorio, morfologia del substrato, composizione chimica del substrato, tipo di copertura del territorio). I dati, sia quelli biotici che abiotici, sono stati inseriti con ArcMap v. 10.3 nel software Maxent v. 3.3. Quest’ultimo è uno SDM che stima la distribuzione della specie con la massima entropia, ossia la più estesa possibile. Data l’impossibilità di ottenere dati futuri per le variabili ambientali non climatiche, per il presente sono stati elaborati modelli di distribuzione dell’antilope nera, considerando sia l’intera gamma di variabili abiotiche sia esclusivamente quelle climatiche. Sono stati inoltre elaborati modelli di distribuzione per gli scenari previsti per il 2050 e il 2070 utilizzando solo le variabili climatiche. In questo modo è stato possibile effettuare un confronto completo della potenziale distribuzione di Hippotragus niger attuale e futura. Ad oggi, utilizzando sia le sole variabili climatiche sia tutte le variabili, le aree più idonee alla sopravvivenza della specie sono anche quelle in cui l’antilope nera è maggiormente presente, ovvero le aree di Northern Province, Mpumalanga, North West e Gauteng (Sudafrica nordorientale). Per quanto attiene le proiezioni future, invece, si prefigura una contrazione delle aree idonee all’antilope nera nelle regioni sopracitate ed una loro espansione in regioni situate più a sud, come lo Swaziland e il KwaZulu-Natal. Al fine di garantire la sopravvivenza a lungo termine della specie oggetto di studio, si suggerisce di concentrare le azioni di conservazione prevalentemente nelle suddette zone, introducendo altri individui in aree adatte, in modo da accrescere la popolazione sul territorio, e tentando di far entrare in contatto le aree idonee nel presente con quelle idonee nel futuro attraverso la creazione di corridoi o di altre aree naturali protette in Sudafrica

Comparing copromicroscopy to intestinal scraping to monitor red fox intestinal helminths with zoonotic and veterinary importance

The red fox acts as reservoir for several helminthic infections which are of interest for both public and animal health. Huge efforts have been made for the assessment of the sensitivity of coprological tests for the detection of Echinococcus multilocularis, while less attention has been paid to other helminthic species. This study aimed at assessing the performance of two copromicroscopic techniques in the detection and prevalence estimation of gastrointestinal helminths in the red fox. Helminths were isolated from the small intestines of 150 red foxes from Bolzano province, Italy, with a scraping, filtration and counting technique (SFCT) and morphologically identified. Rectal contents were collected and submitted to simple flotation (FT) and, only for Taenids, a method based on the concentration of eggs and identification with multiplex PCR (CMPCR). Using SFCT as a reference standard, we estimated the sensitivity of the copromicroscopic tests. Three species of nematodes (namely, Toxocara canis, Uncinaria stenocephala and Pterygodermatites sp.) and five species of cestodes (E. multilocularis, Taenia crassiceps, T. polycantha, Hydatigera taeniaeformis, Mesocestoides sp.) were identified with SFCT, whereas eggs referable to the same taxa were detected with fecal diagnostics, except for Pterygodermatites sp. and Mesocestoides sp. The sensitivity of FT was low for all taxa, ranging from 9.8 to 36.3%, with lower values for Taeniidae. CMPCR was confirmed to perform better for the detection of Taeniidae eggs (23.5%) and the multiplex PCR on retrieved eggs was effective in the identification of the species. A meta-analysis of literature also suggested that our results are consistent with existing data, indicating that copromicroscopy tends to underestimate the prevalence of helminthic infections. The extent of such underestimation varies with taxon, being higher at high prevalence levels, in particular for cestodes. Irregular dynamics of egg shedding, and routine deep freezing of red fox feces may explain the frequency of false negatives with copromicroscopy. Low sensitivity of copromicroscopic tests should be accounted for when estimating prevalence and when defining the correct sample size for the detection of the parasites

Assessing Red Fox (<i>Vulpes vulpes</i>) Demographics to Monitor Wildlife Diseases: A Spotlight on <i>Echinococcus multilocularis</i>

The assessment of red fox population density is considered relevant to the surveillance of zoonotic agents vectored by this species. However, density is difficult to estimate reliably, since the ecological plasticity and elusive behavior of this carnivore hinder classic methods of inference. In this study, red fox population density was estimated using a non-invasive molecular spatial capture-recapture (SCR) approach in two study areas: one in a known hotspot of the zoonotic cestode Echinococcus multilocularis, and another naïve to the parasite. Parasitological investigations on collected samples confirmed the presence of the parasite exclusively in the former area; the SCR results indicated a higher fox population density in the control area than in the hotspot, suggesting either that the relationship between fox density and parasite prevalence is not linear and/or the existence of other latent factors supporting the parasitic cycle in the known focus. In addition, fox spotlight count data for the two study areas were used to estimate the index of kilometric abundance (IKA). Although this method is cheaper and less time-consuming than SCR, IKA values were the highest in the areas with the lower molecular SCR density estimates, confirming that IKA should be regarded as a relative index only

Formaldehyde and Acetaldehyde Exposure in &ldquo;Non-Traditional&rdquo; Occupational Sectors: Bakeries and Pastry Producers

Introduction. Formaldehyde, a colorless and highly irritating substance, causes cancer of the nasopharynx and leukemia. Furthermore, it is one of the environmental mutagens to which humans are most abundantly exposed. Acetaldehyde was recently classified as carcinogen class 1B and mutagen class 2 in Annex VI EC regulation. Occupational exposure to the two aldehydes occurs in a wide variety of occupations and industries. The aim of this study is to deepen exposure to the two aldehydes in the non-traditional productive sectors of bakeries and pastry producers. Methods. The evaluation of exposure to formaldehyde and acetaldehyde was conducted in Italy in 2019, in specific tasks and positions of 11 bakeries and pastry producers (115 measures, of which 57.4% were in fixed positions and the rest were personal air sampling). The measurements were performed using Radiello&copy; radial diffusion samplers. A logarithmic transformation of the data was performed, and the correlation between the two substances was calculated. Moreover, linear models considering the log-formaldehyde as the outcome and adjusting for log-acetaldehyde values were used. Results. The study identified high levels of acetaldehyde and formaldehyde exposure in the monitored workplaces. Higher mean values were observed in the leavening phase (8.39 &micro;g/m3 and 3.39 &micro;g/m3 for log-transformed data acetaldehyde and formaldehyde, respectively). The adjusted univariate analyses show statistically significant factors for formaldehyde as the presence of yeast, the presence of type 1 flour, the use of barley, the use of fats, the type of production, the use of spelt, and the presence of type 0 flour. Conclusions. The measurements confirmed the release of formaldehyde and acetaldehyde in bakeries and pastry industries, especially in some phases of the work process, such as leavening