The status of tuberculosis in European wild mammals

• 1 Tuberculosis (TB) is a chronic disease caused by Mycobacterium bovis and related members of the Mycobacterium tuberculosis complex. Infection affects not only cattle but also other livestock species, companion animals and wild mammals. Humans are also susceptible; hence, zoonotic infection is a driver for disease control in animal hosts. As bovine TB prevalence has been reduced in livestock, the relative epidemiological and socio‐economic importance of wildlife reservoirs has increased, and there is a need for disease management strategies.
• 2 We review the current status of TB in European wild mammals, identifying epidemiological trends and areas for future research and management. TB has a complex epidemiology, which may involve multiple hosts, and is influenced by climate and habitat.
• 3 Consequently, the role of wild and domestic hosts in the epidemiology of TB varies among regions. In Europe, there are three regional examples of M. bovis maintenance hosts: the Eurasian badger Meles meles in Great Britain and Ireland, the Eurasian wild boar Sus scrofa in the Iberian Peninsula and deer belonging to the subfamily Cervinae in several European regions. In other parts of Europe, these species are currently regarded as spillover hosts, although in time their status may change depending on local or regional risk factors. Nevertheless, in most situations, the relative contribution of wild mammals to M. bovis infection in cattle is still a matter of debate. Also, the outcome of management interventions to control disease in wildlife populations may be complex and counter‐intuitive.
• 4 As our knowledge of disease dynamics in wild mammals improves, options for disease control in wildlife reservoirs, such as vaccination, improved biosecurity and population management, are likely to broaden. In order to evaluate our existing control options, we must monitor the effects of interventions on TB occurrence in the affected regions of Europe and share our collective experiences.

     

Genetic diversity in the European wild boar Sus scrofa: phylogeography,population structure and wild x domestic hybridization

• 1 Despite the vast literature on genetic variation in the domestic pig Sus scrofa, little is known about genetic differentiation in wild boar populations.
• 2 Here we present an up‐to‐date review of published data on the past and recent history of the European wild boar, its genetic diversity and the spatial distribution of genetic variation throughout the continent.
• 3 The phylogeography of the species seems to be shaped mostly by past large‐scale events (like postglacial recolonization) rather than by more recent human manipulation. Genetic differentiation is observed both on a continental and a regional scale, and non‐intuitive barriers to gene flow occur.
• 4 From an indirect estimate, hybridization between wild boar and domestic pigs is seemingly a minor source of genetic variation for wild boar populations, yet risks are still linked to the release of captive hybrids in some areas.
• 5 Finally, we present future perspectives concerning the development of powerful molecular tools and their possible application to the study and management of this species.

     

Individual variations in infectiousness explain long-term disease persistence in wildlife populations

Viral disease persistence in species without a reservoir host is of importance for public health and disease management. But how can disease persistence be explained? We developed a spatially‐explicit individual‐based model that takes into account both ecological and viral traits as well as variable space to test disease persistence hypotheses under debate. We introduce a novel concept of modeling alternative disease courses at the individual level, causing transient infections or killing infected animals, with the lethally infected having a variable life‐expectancy. We systematically distinguish between disease invasion and persistence. We use classical swine fever (CSF), an economically very important livestock disease in a social host, the wild boar, as a reference system to test and rank the persistence hypotheses under debate. Parameter values for host population demographics and CSF epidemiology reflect current knowledge. Sensitivity analysis of the model parameters revealed that the most important factor for disease persistence is a disease profile with mostly transient, i.e. surviving individuals requiring immunity, and some chronically, long‐term infected animals. Immune individuals can constantly produce susceptible offspring, while some chronically infected individuals act as ‘super spreaders’ in time. Thus, variations in the course of the disease at the individual level are important factors determining persistence, which is usually not taken into account in the prominent measure of epidemiology, i.e. the basic reproductive number R₀, which reflects the ‘reproductive potential’ of the infected sub‐population. We discuss our results with regard to the general issues of modeling epidemics and disease management issues.     

Towards understanding wild boar Sus scrofa movement: a synthetic movement ecology approach

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Ecological drivers of African swine fever virus persistence in wild boar populations: Insight for control

Environmental sources of infection can play a primary role in shaping epidemiological dynamics; however, the relative impact of environmental transmission on host‐pathogen systems is rarely estimated. We developed and fit a spatially explicit model of African swine fever virus (ASFV) in wild boar to estimate what proportion of carcass‐based transmission is contributing to the low‐level persistence of ASFV in Eastern European wild boar. Our model was developed based on ecological insight and data from field studies of ASFV and wild boar in Eastern Poland. We predicted that carcass‐based transmission would play a substantial role in persistence, especially in low‐density host populations where contact rates are low. By fitting the model to outbreak data using approximate Bayesian computation, we inferred that between 53% and 66% of transmission events were carcass‐based that is, transmitted through contact of a live host with a contaminated carcass. Model fitting and sensitivity analyses showed that the frequency of carcass‐based transmission increased with decreasing host density, suggesting that management policies should emphasize the removal of carcasses and consider how reductions in host densities may drive carcass‐based transmission. Sensitivity analyses also demonstrated that carcass‐based transmission is necessary for the autonomous persistence of ASFV under realistic parameters. Autonomous persistence through direct transmission alone required high host densities; otherwise re‐introduction of virus periodically was required for persistence when direct transmission probabilities were moderately high. We quantify the relative role of different persistence mechanisms for a low‐prevalence disease using readily collected ecological data and viral surveillance data. Understanding how the frequency of different transmission mechanisms vary across host densities can help identify optimal management strategies across changing ecological conditions.     

Multiscale model of regional population decline in little brown bats due to white‐nose syndrome

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Adenovirus: an emerging factor in red squirrel Sciurus vulgaris conservation

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A review of wild boar Sus scrofa diet and factors affecting food selection in native and introduced ranges

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Genetics‐based methods for agricultural insect pest management

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Genetic evidence for introgression between domestic pigs and wild boars (Sus scrofa) in Belgium and Luxembourg: a comparative approach with multiple marker systems

Hybridization between wild species and their domestic relatives can be an important conservation and management problem. Genetic purity of the wild species is desirable per se and the phenomenon can have unpredictable evolutionary consequences. Declining European wild boar populations were frequently restocked with farmed wild boars that sometimes had been crossed with domestic pigs. We used simple polymerase chain reaction‐based diagnostic tests to detect the presence of mitochondrial DNA and coat colour alleles of domestic origin in wild boars from Belgium, Luxembourg, and western Germany. Microsatellite genotypes were used to test for genetic admixture between the wild boars and domestic pigs. Although almost one‐third of all Luxembourg wild boars carried Asian mitochondrial DNA haplotypes originating from domestic pigs, microsatellite‐based clustering only identified four putatively admixed individuals in Luxembourg. By contrast, clustering identified wild boar × domestic hybrids in most sampling locations in Belgium. We interpret these results as evidence of releases of hybrid captive‐reared wild boars. Our results emphasize the need (if working with classical markers) to use different systems to obtain an understanding as to whether hybridization between wild and domestic relatives might have affected the genetic make‐up of a local population. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 104–115.     

Removal of chronic Mycoplasma ovipneumoniae carrier ewes eliminates pneumonia in a bighorn sheep population

1. Chronic pathogen carriage is one mechanism that allows diseases to persist in populations. We hypothesized that persistent or recurrent pneumonia in bighorn sheep (Ovis canadensis) populations may be caused by chronic carriers of Mycoplasma ovipneumoniae (Mo). Our experimental approach allowed us to address a conservation need while investigating the role of chronic carriage in disease persistence.
2. We tested our hypothesis in two bighorn sheep populations in South Dakota, USA. We identified and removed Mo chronic carriers from the Custer State Park (treatment) population. Simultaneously, we identified carriers but did not remove them from the Rapid City population (control). We predicted removal would result in decreased pneumonia, mortality, and Mo prevalence. Both population ranges had similar habitat and predator communities but were sufficiently isolated to preclude intermixing.
3. We classified chronic carriers as adults that consistently tested positive for Mo carriage over a 20‐month sampling period (n = 2 in the treatment population; n = 2 in control population).
4. We failed to detect Mo or pneumonia in the treatment population after chronic carrier removal, while both remained in the control. Mortality hazard for lambs was reduced by 72% in the treatment population relative to the control (CI = 36%, 91%). There was also a 41% reduction in adult mortality hazard attributable to the treatment, although this was not statistically significant (CI = 82% reduction, 34% increase).
5. Synthesis and Applications: These results support the hypothesis that Mo is a primary causative agent of persistent or recurrent respiratory disease in bighorn sheep populations and can be maintained by a few chronic carriers. Our findings provide direction for future research and management actions aimed at controlling pneumonia in wild sheep and may apply to other diseases.

     

The role of age of first breeding in modeling raptor reintroductions

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The importance of fine‐scale predictors of wild boar habitat use in an isolated population

1. Predicting the likelihood of wildlife presence at potential wildlife–livestock interfaces is challenging. These interfaces are usually relatively small geographical areas where landscapes show large variation over small distances. Models of wildlife distribution based on coarse data over wide geographical ranges may not be representative of these interfaces. High‐resolution data can help identify fine‐scale predictors of wildlife habitat use at a local scale and provide more accurate predictions of species habitat use. These data may be used to inform knowledge of interface risks, such as disease transmission between wildlife and livestock, or human–wildlife conflict.
2. This study uses fine‐scale habitat use data from wild boar (Sus scrofa) based on activity signs and direct field observations in and around the Forest of Dean in Gloucestershire, England. Spatial logistic regression models fitted using a variant of penalized quasi‐likelihood were used to identify habitat‐based and anthropogenic predictors of wild boar signs.
3. Our models showed that within the Forest of Dean, wild boar signs were more likely to be seen in spring, in forest‐type habitats, closer to the center of the forest and near litter bins. In the area surrounding the Forest of Dean, wild boar signs were more likely to be seen in forest‐type habitats and near recreational parks and less likely to be seen near livestock.
4. This approach shows that wild boar habitat use can be predicted using fine‐scale data over comparatively small areas and in human‐dominated landscapes, while taking account of the spatial correlation from other nearby fine‐scale data‐points. The methods we use could be applied to map habitat use of other wildlife species in similar landscapes, or of movement‐restricted, isolated, or fragmented wildlife populations.

     

Dogs Canis familiaris as carnivores: their role and function in intraguild competition

• 1 Dogs Canis familiaris are the world's most common carnivore and are known to interact with wildlife as predators, prey, competitors, and disease reservoirs or vectors.
• 2 Despite these varied roles in the community, the interaction of dogs with sympatric wild carnivore species is poorly understood. We review how dogs have been classified in the literature, and illustrate how the location and ranging behaviour of dogs are important factors in predicting their interactions with wild prey and carnivores.
• 3 We detail evidence of dogs as intraguild competitors with sympatric carnivores in the context of exploitative, interference and apparent competition.
• 4 Dogs can have localized impacts on prey populations, but in general they are not exploitative competitors with carnivores. Rather, most dog populations are highly dependent on human‐derived food and gain a relatively small proportion of their diet from wild prey. However, because of human‐derived food subsidies, dogs can occur at high population densities and thus could potentially outcompete native carnivores, especially when prey is limited.
• 5 Dogs can be effective interference competitors, especially with medium‐sized and small carnivores. Dogs may fill the role of an interactive medium‐sized canid within the carnivore community, especially in areas where the native large carnivore community is depauperate.
• 6 Dogs can also be reservoirs of pathogens, because most populations around the world are free‐ranging and unvaccinated. Diseases such as rabies and canine distemper have resulted in severe population declines in several endangered carnivores coexisting with high‐density dog populations. Dogs can therefore be viewed as pathogen‐mediated apparent competitors, capable of facilitating large‐scale population declines in carnivores.
• 7 Based on this information, we propose conceptual models that use dog population size and ranging patterns to predict the potential for dogs to be intraguild competitors. We discuss how interactions between dogs and carnivores might influence native carnivore communities.

     

Biogeographical variation in the population density of wild boar (Sus scrofa) in western Eurasia

Aim We reviewed 54 studies reporting population densities of wild boar (Sus scrofa) in western Eurasia in order to investigate the roles of vegetation productivity [fraction of photosynthetically active radiation (FPAR) index], winter harshness (mean January temperature) and presence/absence of wolves (Canis lupus) in shaping the biogeographical variation in population density of wild boar. Location We collected published data on the autumn–winter population density of wild boar (number of individuals km^?2) in 54 locations in western Eurasia, from 1966 to 2003. Methods The mean January temperature, obtained from the World Climate data base ( http://www.worldclimate.com ), was taken as a measure of winter severity. We used monthly 4 × 4 km MODIS FPAR data sets covering January 2000 to June 2004 to calculate the vegetation productivity index. In addition, we collected literature data about the presence or absence of wolves from the study areas. Results In the geographical span of 37–60° N, the population densities of wild boar declined by three orders of magnitude, from 10 to 0.01 individuals km^?2. The best multiple regression model (selected with the Akaike information criterion corrected for small samples) showed that mean January temperature and the vegetation productivity index were the most important factors explaining the biogeographical variation in population densities of wild boar. The impact of temperature was stronger than that of productivity. The presence of wolves had a weak limiting effect on population densities of wild boar at the biogeographical scale. Main conclusion We propose that winter harshness imposes density‐independent mortality on wild boar populations at higher latitudes. Competition for food in less productive regions may cause stronger density dependence in birth and death rates of wild boar populations. We expect that wild boar will respond to global warming by both an increase in local population densities and an expansion of their geographical range north and north‐eastwards.     

Slovenian Students’ Knowledge and Opinions about Wild Boar (Sus Scrofa L.)

ABSTRACT

Wild boar are present almost throughout Slovenia, causing similar problems as in many other countries, mainly damage to agriculture. Dealing with these problems also involves children. The aim of this study was to assess the effects of age, gender, and farm residence on knowledge, attitudes, and opinions about wild boar management in 11- and 15-year-olds (n = 478) attending schools in/near areas of high wild boar densities, via an anonymous closed-ended questionnaire. Only 52.4% of the questions on factual knowledge were answered correctly, although a relatively high proportion of students (38.3%) reported having seen wild boar in their natural environment. The majority of students (81.4%) expressed affection toward animals in general, while only 11.3% stated that they liked wild boar. The main source of information about these animals was home (40.0%), followed by school (26.1%). Logistic regression analysis revealed that students’ age and gender usually predicted their response (p < 0.05), while living on a farm influenced only the source of information and one attitude question: farm residents were more likely to express affection toward wild boar. The older students were more likely to know more about wild boar, but they also were more likely to be indifferent toward the species. Boys and girls did not differ in their knowledge, but girls were more likely to express fear/dislike of wild boar. In general, older students and girls were more likely to be undecided in their responses. Since we found almost no effect of farm residence on students’ knowledge and opinions, it can be concluded that wild boar problems are recognized generally, not only in agriculture. Because information from home can be biased, we propose that teachers be encouraged to include wild boar topics in their teaching, educating young people properly about wild boar problems and consequently influencing their adult behavior concerning management issues.     

Domestication of tomato has reduced the attraction of herbivore natural enemies to pest‐damaged plants

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Behavior underpins the predictive power of a trait‐based model of butterfly movement

1. Dispersal ability is key to species persistence in times of environmental change. Assessing a species' vulnerability and response to anthropogenic changes is often performed using one of two methods: correlative approaches that infer dispersal potential based on traits, such as wingspan or an index of mobility derived from expert opinion, or a mechanistic modeling approach that extrapolates displacement rates from empirical data on short‐term movements.
2. Here, we compare and evaluate the success of the correlative and mechanistic approaches using a mechanistic random‐walk model of butterfly movement that incorporates relationships between wingspan and sex‐specific movement behaviors.
3. The model was parameterized with new data collected on four species of butterfly in the south of England, and we observe how wingspan relates to flight speeds, turning angles, flight durations, and displacement rates.
4. We show that flight speeds and turning angles correlate with wingspan but that to achieve good prediction of displacement even over 10 min the model must also include details of sex‐ and species‐specific movement behaviors.
5. We discuss what factors are likely to differentially motivate the sexes and how these could be included in mechanistic models of dispersal to improve their use in ecological forecasting.

     

Modeling the distribution of a wide‐ranging invasive species using the sampling efforts of expert and citizen scientists

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