Nicola Ferrari

Invasive alien species are a recognised threat to biodiversity, ecosystem functions, and human well-being. Management efforts often prioritise ecological and economic outcomes, neglecting the implications of control methods on animal welfare. We investigated the perceived impacts on animal welfare of different lethal and non-lethal methods to control invasive slider turtles Trachemys scripta in Europe. We elicited the opinions of a group of 24 herpetologists, turtle caretakers, veterinarians and welfare experts, combining the Five Domains welfare framework with a formal structured elicitation approach. Experts generally agreed that welfare impacts in traps or transport would be mostly minor, but could increase with time of exposure, turtle densities and inadequate protocols. For captive containment post-capture, concerns included inadequate diets and habitats, disease and behavioural concerns, although the latter were particularly uncertain. For lethal methods, lethal injection and properly executed shooting were judged to cause no or mild suffering only. Self-expressed confidence in the elicited estimates was relatively high, but decreased for higher impact levels, longer timeframes and less-known welfare domains such as behavioural concerns. Future research would refine welfare assessment models, particularly for the evaluation of cumulative impacts across different methods and multiple affected individuals. However, in a field as multifaceted as animal welfare, some degree of expert interpretation will likely always be necessary to guide policy: structured expert elicitation can help formalise current knowledge and make those interpretations more transparent.

Shared pathogens can alter the interaction between native and alien species resulting in disease-mediated invasions (DMIs). Invasive animals often harbour low-virulence macroparasites, but empirical evidence for macroparasite-driven DMIs is still limited due to their subtile pathological impacts and scarce prominence. Here, we modelled the dynamics of native red squirrels, invasive grey squirrels and their shared nematode Strongyloides robustus to assess whether macroparasites can drive DMIs and lead to native species extinction. Our simulations showed that spill-over of the alien parasite can lead to red squirrel extinction, that grey squirrels can amplify the infection in the native host and that the infection can accelerate the replacement of red squirrels compared to direct competition alone, ultimately facilitating invasion by grey squirrels. These results show that low-virulence macroparasites can potentially mediate animal invasions, suggesting that we are overlooking key drivers of native species decline.

Qualitative frameworks are widely employed to tackle urgent animal or public health issues when data are scarce and/or urgent decisions need to be made. In qualitative models, the degree of belief regarding the probabilities of the events occurring along the risk pathway(s) and the outcomes is described in nonnumerical terms, typically using words such as Low, Medium, or High. The main methodological challenge, intrinsic in qualitative models, relates to performing mathematical operations and adherence to the rule of probabilities when probabilities are nonnumerical. Although methods to obtain the qualitative probability from the conditional realization of n events are well‐established and consistent with the multiplication rule of probabilities, there is a lack of accepted methods for addressing situations where the probability of an event occurring can increase, and the rule of probability P(AUB) = P(A) + P(B) − P(A∩B) should apply. In this work, we propose a method based on the pairwise summation to fill this methodological gap. Our method was tested on two qualitative models and compared by means of scenario analysis to other approaches found in literature. The qualitative nature of the models prevented formal validation; however, when using the pairwise summation, results consistently appeared more coherent with probability rules. Even if the final qualitative estimate can only represent an approximation of the actual probability of the event occurring, qualitative models have proven to be effective in providing scientific‐based evidence to support decision‐making. The method proposed in this study contributes to reducing the subjectivity that characterizes qualitative models, improving transparency and reproducibility.

Parasites can modify host behaviour to increase their chances of survival and transmission.Toxoplasma gondiiis a globally distributed protozoan whose ability to modify host behaviour is well known in taxa such as rats and humans. Less well known are the effects on the behaviour of wild species, with the exception of a few studies on primates and carnivores. Taking advantage of a culling activity conducted in Stelvio National Park (Italy), the serological status ofT. gondiiwas studied in 260 individuals of red deerCervus elaphuswith respect to the risk of being culled. A temporal culling rank index was fitted as a response variable, andT. gondiiserological status as the main explanatory variable in linear models, accounting for covariates such as sex, age, jaw length, bone marrow fat and culling location. The overall seroprevalence ofT. gondiiwas 31.5%, and the selected models suggested that seropositive deer were culled earlier than seronegative ones, but this effect was only evident in females, in individuals with medium–good body condition, and in areas with greater human presence. Our results suggest thatT. gondiimay be involved in risk behaviour in large herbivores, supporting its role as a facilitator of predation risk.

Collection from jugular vein (JV) or intrathoracic cavity is the traditional procedure for blood sampling dead wildlife, but it is often source of preanalytical biases. Cavernous sinus of dura mater (CS) is an alternative site for withdrawal that may help to solve these issues but it has been used only for serology, while no data are available for biochemistry. This work compares metabolic profiles from CS and JV blood in red deer Cervus elaphus, to evaluate the usability of CS for metabolic profiling. A total of 134 deer were sampled in the frame of a culling program within the Stelvio National Park (Central Italian Alps). Hemolysis was statistically lower in CS than JV with 88% vs 44% of samples suitable for biochemistry. Thirty-six couples of poorly hemolytic sera were used for biochemical analysis: total protein, albumin, urea, triglycerides, total cholesterol, non-esterified fatty acids (NEFA), betahydroxybutyrate (BOHB), calcium, and phosphorus. Statistical differences were found for protein, albumin, cholesterol, and calcium; agreement was found for urea, NEFA, BOHB, and phosphorus while for total protein, albumin, cholesterol, and calcium, CS showed lower concentrations with both constant and proportional biases. These results may be related to a higher impact of water dilution in CS. Although the lower protein concentration in CS cannot significantly influence the serological results, caution is required for potential false negative results when antibody levels are close to cut-off values. CS leads to a higher percentage of samples suitable for metabolic profiles but results should be compared with adequate reference intervals.

West Nile disease is a vector-borne disease caused by West Nile virus (WNV), involving mosquitoes as vectors and birds as maintenance hosts. Humans and other mammals can be infected via mosquito bites, developing symptoms ranging from mild fever to severe neurological infection. Due to the worldwide spread of WNV, human infection risk is high in several countries. Nevertheless, there are still several knowledge gaps regarding WNV dynamics. Several aspects of transmission taking place between birds and mosquitoes, such as the length of the infectious period in birds or mosquito biting rates, are still not fully understood, and precise quantitative estimates are still lacking for the European species involved. This lack of knowledge affects the precision of parameter values when modelling the infection, consequently resulting in a potential impairment of the reliability of model simulations and predictions and in a lack of the overall understanding of WNV spread. Further investigations are thus needed to better understand these aspects, but field studies, especially those involving several wild species, such as in the case of WNV, can be challenging. Thus, it becomes crucial to identify which transmission processes most influence the dynamics of WNV. In the present work, we propose a sensitivity analysis to investigate which of the selected epidemiological parameters of WNV have the largest impact on the spread of the infection. Based on a mathematical model simulating WNV spread into the Lombardy region (northern Italy), the basic reproduction number of the infection was estimated and used to quantify infection spread into mosquitoes and birds. Then, we quantified how variations in four epidemiological parameters representing the duration of the infectious period in birds, the mosquito biting rate on birds, and the competence and susceptibility to infection of different bird species might affect WNV transmission. Our study highlights that knowledge gaps in WNV epidemiology affect the precision in several parameters. Although all investigated parameters affected the spread of WNV and the modelling precision, the duration of the infectious period in birds and mosquito biting rate are the most impactful, pointing out the need of focusing future studies on a better estimate of these parameters at first. In addition, our study suggests that a WNV outbreak is very likely to occur in all areas with suitable temperatures, highlighting the wide area where WNV represents a serious risk for public health.