Sarcoptic Mange in Wild Caprinae of the Alps: Could Pathology Help in Filling the Gaps in Knowledge?

Sarcoptic mange represents the most severe disease for wild Caprinae individuals and populations in Europe, rising concerns for both conservation and management of these ungulates. To date, this disease has been investigated in different wild caprine species and under many different perspectives including diagnostics, epidemiology, impact on the host populations and genetics of both hosts and parasite, with the aim to disentangle the host-Sarcoptes scabiei relationship. Notwithstanding, uncertainty still remains and basic questions still need an answer. Among these, the effect of immunological responses on mange severity at an individual level, the main drivers in host-parasite interactions for different clinical outcomes and the role of the immune response in determining the shift from epidemic to endemic cycle. A deeper approach to pathology of this disease seems therefore advisable, all the more reason considering that immune response to S. scabiei in wild Caprinae, generally classified as a hypersensitivity, still remains poorly understood. In this paper, we started a journey into the pathological features associated to sarcoptic mange in wildlife, exploring different kinds of hypersensitivity and outcomes, with the final goal to highlight the major drivers in the different responses to this disease at an individual level and propose some key topics for future research, with a particular attention to Alps-dwelling wild caprines

Spatial and time explorative analyses on 15 years of passive surveillance and serological monitoring for scabies in the alpine chamois population of the Belluno province (Italy)

Background - Sarcoptic mange is one of the most severe diseases of wild Caprinae populations in Europe, raising concerns about wildlife management and conservation. Since 1995, an epidemic of sarcoptic mange has been affecting the chamois (Rupicapra r. rupicapra) population of the dolomitic area, in the North Eastern Italian Alps, involving also the sympatric ibex (Capra ibex) populations. The index case was found in the province of Belluno, where the disease is still spreading and where are now present different epidemiological situations: free areas, epidemic areas, endemic areas with sporadic cases, and an endemic area showing a second clinical peak about 15 years from the index case. In the past years, different approaches have been attempted to control scabies and to better understand the dynamics of this disease. Among these, ELISA serological methods have been applied on chamois shot during the regular hunting seasons, mainly in free areas, as an attempt to anticipate the arrival of the clinical disease. Notwithstanding, these attempts showed contradictory results, due to the difficulties in both interpreting serological evidences and defining an epidemic front to compare with. Methods - Starting from raw data of 1168 scabies-affected chamois carcases found from 1995 to 2010, and 2735 shot chamois tested for antibodies to Sarcoptes scabiei on lung extract from 2001 to 2009, we propose an explorative approach in the Belluno province. This approach, implemented by time series analysis and a geographic information system (GIS), explores the scabies epidemic in chamois, its front and the seropositivity distribution in space and time using, instead of the index cases, the centroid of the mountain massifs during their own epidemic peaks and/or the coordinate mean of the clinical mange cases in each year as epidemiological units and geographical benchmarks. Results and discussion - regarding clinical cases, time series analysis confirmed previous studies, showing the main incidence of the disease during late winter/early spring. The scabies front appears to spread in a south-westward direction with a mean estimated speed of 5\ub13.7 km/year, which is comparable with the results of previous studies in the same area. Considering the serological results in comparison to scabies cases, an interesting and quite regular pattern was observed, as the earliest serological positive case in different massifs anticipates the earliest clinical cases of 5-6 years. The average distance between epidemic front and the first serological positivity is more than 25 Km. These results appear unexpected, and should be confirmed by further analyses to be performed in neighbouring areas, namely Trento and Bolzano provinces. If these result will be confirmed, they would represent a significant step in the knowledge of S. scabiei ecology and potential impact in the alpine chamois populations

A farm-scale sustainability assessment of the anaerobic digestate application methods

Digestate is the anaerobic digestion by-product that can be used as an organic fertilizer, but some agronomic and environmental concerns still hinder its application on land. This study aims to evaluate the agronomic performances (i.e., silage maize dry yield, protein content, and N uptake) and environmental sustainability of solid and liquid digestate fraction application in a field experiment involving two farms with different textures covering about 47 ha in North Italy. The best available distribution methods included mineral fertilizer (MF), mineral fertilizer in variable rate application (VRA) (VRA-MF), liquid digestate with a nitrification inhibitor (LD+), liquid digestate in VRA (VRA-LD), liquid digestate with a nitrification inhibitor in VRA (VRA-LD+), and solid digestate (SD) and were applied to silage maize (Zea mays L.) in 2019 and 2020 cropping seasons. Results showed that both digestate fractions gave satisfying agronomic performances (i.e., dry biomass > 13 t ha-1 and protein content > 6.8%), comparable to those of mineral fertilizers, irrespective of soil type and application techniques. On the contrary, system sustainability investigated with a spatial evaluation of nitrogen use efficiency (NUE) revealed a strong interaction between NUE and soil texture. Indeed, in fine-textured soil only the adoption of both VRA and the nitrification inhibitor allowed the liquid digestate to reach a NUE between 50% and 90% while SD exhibited poor NUE (e.g., < 50%). In conclusion, liquid digestate fraction might be an effective substitute for mineral fertilizers in silty soils meeting also environmental criteria when VRA or nitrification inhibitors are applied. Contrarily, longer-term experiments are requested to evaluate SD fraction sustainability