BACKGROUND
bovine tuberculosis  is a chronic infectious disease that causes significant economic losses worldwide.
mycobacterium bovis, the main causative agent of the disease, is transmitted between a variety of domestic and wild animals, and humans
<cit> .
m. bovis is primarily transmitted by aerosols and may persist for long periods in the environment, especially in moist and shady zones, such as the water points or the woodlands
<cit> .
due to its widespread distribution and the sanitary and economic impact, eradication of btb is considered a priority in the european union
<cit> .
a great amount of personal and financial resources are invested every year in order to control the disease.
control and preventive sanitary programs for btb eradication have been conducted for decades and traditionally focused on cattle, mainly consisting of culling reactor animals to the intradermal tuberculin test .
despite these efforts, the disease remains prevalent or even increasing in many regions of the world, most likely associated to wild mammal reservoirs
<cit> .
several studies have highlighted the role of certain wildlife species as major reservoirs, depending on the ecosystem and the region of the world
<cit> .
among the wild mammals in spain, the eurasian wild boar  and the red deer  constitute the most important reservoirs, especially in mediterranean areas, because they are able to maintain and efficiently transmit the agent in the absence of other domestic or wild hosts
<cit> .
the implication of wildlife species in this multi-host cycle, in addition to many environmental and ecological factors, probably hampers the success in the control of btb and makes the complete eradication of the disease currently not feasible
<cit> .
despite the national and long-lasting coverage of the btb eradication plans in spain, the prevalence of btb varies considerably between regions
<cit> .
in  <dig>  while disease presence was negligible in the islands and low in the north-east part of the country , the herd prevalence in some regions of central, southern and western spain was considerably higher, reaching values up to  <dig> % in castile-la mancha
<cit> .
there are several epidemiological circumstances that might be favouring this situation.
first, cattle herds are farmed especially for beef , comprising breeds of animals difficult to deal with due to their strong character.
this kind of cattle is managed in extensive mediterranean conditions in areas with difficult access, unfavourable topography and lack of resources, which makes it quite difficult to properly test all the animals of the herd.
this also induces common grazing and a shared use of scarce water points , and thus, the contact of cattle with other domestic livestock such as sheep, goats, pigs
<cit>  and wildlife
<cit> .
secondly, some areas, especially in the south central regions, have experienced a great development in the recreational hunting industry, which leads to overabundance of wild ungulates in which sanitary programs cannot be implemented, leading to high prevalence of diseases
<cit> .
all these aspects promote the existence of a wildlife-domestic livestock interface in mediterranean habitats that could maintain a multihost environmental reservoir for m. bovis <cit> .
however, there is no research on the association between these factors and the status of btb at either fine or large spatial scales.
in fact, regional variations in btb eradication strategies through spain are mainly based on the cattle animal/herd prevalence or incidence rates, data obtained from the national programmes for btb eradication
<cit> .
the first contribution of the risk concept to the sanitary strategies appears in the literature only very recently
<cit> , although there is a lack of inclusion and evaluation of wildlife-related risk factors.
moreover, the marked spatial variability in btb risks indicates that we need detailed approaches in particular areas to evaluate different cattle management, environmental and biogeographical factors
<cit> .
characterization of risk factors for tb occurrence are crucial to more cost-effectively allocate financial and personal resources in order to improve the preventive, control and eradication measures in spain and other regions with similar epidemiological conditions.
here we focus on an area from south central spain  characterized by a complex epidemiological scenario for btb, with the existence of a wildlife-domestic livestock interface under mediterranean conditions and presence of abundant, widely distributed wild ungulate populations where tb is endemic and highly prevalent
<cit> .
in this epidemiological context we used a bayesian model to explore the nature and extent of the association between the distribution of m. bovis infection and potential risk factors in relation to cattle, wild ungulates and environmental aspects.
this study is intended to guide policy makers towards risk-based and cost-effective tb eradication strategies.
RESULTS
tb occurrence in ciudad real municipalities was spatially clustered in  <dig>  as indicated by the visual inspection of the spatial distribution of disease and the spatial cluster identified  .
the model with no predictors  had a dic of  <dig> .
the final model that best fitted the data  included  <dig> variables ; three of them  were statistically significant  and positively  associated with tb occurrence .
the number of sampled animals in the cattle farms  included in the sanitary plan in  <dig>  the number of cattle farms with at least one btb-positive animal in  <dig>  the number of tb-positive red deer in  <dig>  and the proportion of cattle farms classified as breeding farms in  <dig> were marginally statistically significant .
the number of farms for bullfighting cattle appeared to improve to final model, although it was not highly significant.
the spatial distribution of the variables included in the final model is shown in figure
<dig>
= quantitative standardized variable;  = dichotomous variable .
: significant coefficients of the final model using the 95% ci.
: significant coefficients of the final model using the 90% ci.
the posterior probability of tb occurrence in ciudad real estimated by the best fitting model resembled the spatial structure of the disease observed in the data, with areas at the highest risk concentrated in the northwest corner, the southwest part and several municipalities in the southern stripe of the region .
both si and ui were very low , which may indicate no significant presence in the model of spatial autocorrelation and overdispersion over-and-above the risk factors identified, as well as a good fit of the model .
in addition, convergence of the model was obtained after the first  <dig> iterations and no problems with autocorrelation were identified for the posterior inferences.
discussion
in this study we aimed to explore the nature and extent of the association between potential risk factors and tb occurrence in wild ungulates and cattle in one of the most tb-prevalent regions of spain referred to as ciudad real.
the proportion of cattle farms becoming btb positive in  <dig>  the mean number of hunting seasons in which the hunting estates of the municipality have been inspected and the apparent prevalence of tb in wild boar in  <dig> were identified as the most relevant factors related to the tb occurrence in  <dig> in ciudad real.
these factors are useful predictors in planning disease control strategies.
results revealed that both livestock- and wildlife-related factors determine tb presence at spatial scale.
overall, the major risk factor for tb incidence in any given year is whether it was present or not, and at what level, in the previous year.
the probability of tb occurrence in ciudad real resembled the biogeography of the province as well as game and cattle farming distribution, with areas at high risk concentrated in the municipalities with a higher proportion of forest or natural habitats , and the highest big game activity.
in fact, the mean number of hunting seasons in which the hunting estates of the municipality have been inspected, which is an indicator of the hunting activity in the municipality, remained statistically significant in the model .
usually, woodlands and savannah-like areas  are dedicated to big game, whereas marginal dehesas are located in the valleys in close proximity, where land is not appropriate for agriculture, are mainly dedicated to extensive livestock farming.
this distribution, together with particular mediterranean features that favour the wildlife-livestock interface  may explain how tb could be transmitted from wildlife to livestock and vice versa .
however, from this study we cannot infer the directionality of m. bovis transmission, i.e.
whether wildlife reservoirs are infecting cattle, or whether cattle is the responsible of the circulation of m. bovis in both domestic and wild hosts.
in fact, it could be the case that some municipalities with a high prevalence of tb in just one species  in  <dig> may be purely correlated with a high prevalence of tb in only that species  the previous year.
this would indicate no inter-species transmission in some regions.
however, ciudad real municipalities with this scenario are an exception  and many tb-infected regions presented tb cases in more than one species  .
this suggests a potential multi-species interaction scenario.
unfortunately, we cannot prove this because the final model did not include any interaction between variables related to hosts.
nevertheless, future studies should reveal whether the presence of the disease in wildlife is associated with increased presence of the disease in livestock and establish the directionality and extent of the tb inter-species transmission.
the finding that municipalities with a high proportion of cattle farms becoming btb positive in  <dig> were at high risk for tb occurrence in  <dig>  is an indicator that tb until  <dig> repeatedly tends to appear in the same municipalities.
these findings are in agreement with the trend of incidence and persistence of btb in south central spain during 2006– <dig>  particularly in ciudad real, observed in previous studies
<cit> .
this indicates the persistence of the pathogen over consecutive sanitary campaigns despite the eradication efforts and the culling of positive animals.
herd-level research is needed to elucidate whether barriers imposed to prevent the transmission of m. bovis into btb-free farms are not as efficient as expected, or diagnostics were not reliable enough in presumed free farms.
both of these risk factors have not been explored in this study.
most of the extensive farms and cattle census in ciudad real province are located in municipalities where some of the risk factors identified in this model may operate, such as wildlife tb reservoir abundance .
although the tb inspection in spain is compulsory in all cattle farms, these aspects also show that the efforts in controlling m. bovis infection in the whole cattle stock should not be relaxed, especially in extensive farms where enclosing and handling the whole stock is more difficult.
our final model suggests that the higher the number of cattle submitted to the sanitary campaigns, the higher the likelihood of the municipality to be tb positive the following year .
as brooks-pollock and keeling
<cit>  reported, many elements associated with herd size could contribute to disease persistence within a herd, such as an increased number of movements or larger land coverage with increased risk of environmental contamination, or more densely stocked cattle.
nonetheless, this should be evaluated at the herd level.
although the information regarding tb prevalence in wildlife is usually not available and more difficult to obtain than in cattle, we believe that it is also crucial to monitor the tb status of wild reservoirs in a region
<cit> .
in fact, one of the significant covariates in the final model is the mean number of hunting seasons in which the hunting estates of the municipality have been inspected , which is related to the intensity and sustainability of the hunting activity performed in each estate over time, and therefore the abundance of big game.
in addition, the analysis revealed two additional major risk factors related to wild hosts: the apparent prevalence of tb in wild boar  and the number of tb-positive red deer  both in the previous year.
the implication of wild boar and red deer in the tb presence and maintenance in south central spain has been previously suggested
<cit> ; the wild boar showing higher tb prevalence than red deer
<cit> .
in addition, wild boar has been proposed as the most relevant wild host of m. bovis in spain
<cit>  becoming a true tb reservoir in the iberian peninsula
<cit> .
this importance is enhanced by its abundance in europe, the high levels of infection observed in this species, its ability to disseminatethe pathogen, its scavenging behaviour and, mostly, its potential ability for crossing fences and contacting with livestock
<cit> .
given this situation, physical biosafety practices may serve as a means to cost-effectively prevent contact between wild and domestic mammals and thus tb inter-species transmission.
this is particularly useful in those areas where the hunting industry plays an important role in the local economy, such as ciudad real.
also, any action conducted to reduce tb prevalence and mycobacteria spreading in wild ungulates should contribute to reduce the m. bovis transmission risk at the wildlife-livestock interface.
options include the management of host density, spatial aggregations at supplementary feeding sites or waterholes, the safe disposal of carrion and viscera by hunters, and oral vaccination
<cit> .
there is evidence supporting the inter-species circulation of m. bovis <cit>  and several studies have recently confirmed the presence of the same m. bovis spoligotypes in cattle and wild fauna sharing the same area
<cit> .
m. bovis transmission between wild and domestic animals may occur directly via close contact, or indirectly via contamination of food or the environment with m. bovis.
most of the btb control programmes in developed countries are mainly directed towards livestock not including wildlife, even where it is obviously involved in disease maintenance.
the lack of integral control strategies is more evident in extensive cattle, which is the sector mostly exposed to wildlife contacts
<cit> .
this was supported previously
<cit>  and in our results, since the proportion of cattle farms classified as extensive beef breeding farms  and the number of farms devoted to bullfighting cattle were revealed as risk factors in the final model .
both types of farms are integrated in natural pasture agrosystems in close proximity with wildlife.
however, the inclusion of these two covariates related to extensive cattle farming reinforces the idea that sanitary programs should incorporate the wildlife interface, especially in those cattle farms most exposed to m. bovis infection, as has been done in spain since  <dig> .
the bayesian mixed effects multivariable logistic regression model was chosen as the best statistical approach to be used in this study.
the reason is because the bayesian methodology solves most of the problems faced by traditional statistical methods, e.g.
the spatial autocorrelation, the potential dependence between the covariates or the incorporation of variables with few observations.
the unit of analysis  was also considered adequate given the information that was available and the spatial level at which policies are taken.
however, as any ecological study, some of the results may be biased as a consequence of the artificial grouping of observations and variables at the municipality level.
in addition, differences in the municipality size may confound the interpretation of the maps, since the largest municipalities could appear at the highest risk only because they entail the majority of the observations
<cit> .
although variations in size among municipalities are not particularly large in the study area, we have used proportions in the majority of the covariates to minimize this problem.
despite these limitations, the approach used here is very useful for the exploration of spatially aggregated data and to highlight the most risky areas to perform more accurate analysis.
the model proposed in this article is robust and consistent, as shown by the much lower dic of the final model  and the small sd of si  and ui .
the robustness and consistence of this model allow to study the “tb hot spots” of the province in detail, since future epidemiological analyses at more local scale may be conducted.
CONCLUSIONS
in this study we used a bayesian mixed effects spatial model that controlled for unobserved spatial and non-spatial heterogeneity over-and-above a set of risk factor variables considering environment, wildlife and cattle epidemiological factors.
overall, the major risk factor for tb incidence at any given year is whether or not it was present, and at what level, in the previous year.
our results support that cattle and big game  are both involved in the m. bovis circulation in this region, evidencing a clustered distribution in the western part and an endemicity of the disease in many municipalities.
in addition, some characteristics of management and surveillance in this region seem to be linked to tb occurrence.
all these findings may guide sanitary authorities to conduct efforts towards specific areas and epidemiological situations where the wildlife-livestock interface seems to critically hamper the definitive success of the btb eradication program.
we believe that the inclusion of wild animals in control and eradication programmes, and the development of efficient biosafety practices in extensive farms should be a priority to eradicate the disease in livestock.
further studies are needed in order to understand the complex multi-host interaction at the farm level to more precisely evidence directionality of transmission and risks factors associated to tb.

 bovine tuberculosis is a chronic infectious disease that causes significant economic losses worldwide. mycobacterium bovis, the main causative agent of the disease, is transmitted between a variety of domestic and wild animals, and humans. m. bovis is primarily transmitted by aerosols and may persist for long periods in the environment, especially in moist and shady zones, such as the water points or the woodlands. due to its widespread distribution and the sanitary and economic impact, eradication of btb is considered a priority in the european union. a great amount of personal and financial resources are invested every year in order to control the disease. control and preventive sanitary programs for btb eradication have been conducted for decades and traditionally focused on cattle, mainly consisting of culling reactor animals to the intradermal tuberculin test. despite these efforts, the disease remains prevalent or even increasing in many regions of the world, most likely associated to wild mammal reservoirs. several studies have highlighted the role of certain wildlife species as major reservoirs, depending on the ecosystem and the region of the world. among the wild mammals in spain, the eurasian wild boar and the red deer constitute the most important reservoirs, especially in mediterranean areas, because they are able to maintain and efficiently transmit the agent in the absence of other domestic or wild hosts. the implication of wildlife species in this multi-host cycle, in addition to many environmental and ecological factors, probably hampers the success in the control of btb and makes the complete eradication of the disease currently not feasible. despite the national and long-lasting coverage of the btb eradication plans in spain, the prevalence of btb varies considerably between regions. in while disease presence was negligible in the islands and low in the north-east part of the country, the herd prevalence in some regions of central, southern and western spain was considerably higher, reaching values up to % in castile-la mancha. there are several epidemiological circumstances that might be favouring this situation. first, cattle herds are farmed especially for beef, comprising breeds of animals difficult to deal with due to their strong character. this kind of cattle is managed in extensive mediterranean conditions in areas with difficult access, unfavourable topography and lack of resources, which makes it quite difficult to properly test all the animals of the herd. this also induces common grazing and a shared use of scarce water points, and thus, the contact of cattle with other domestic livestock such as sheep, goats, pigs and wildlife. secondly, some areas, especially in the south central regions, have experienced a great development in the recreational hunting industry, which leads to overabundance of wild ungulates in which sanitary programs cannot be implemented, leading to high prevalence of diseases. all these aspects promote the existence of a wildlife-domestic livestock interface in mediterranean habitats that could maintain a multihost environmental reservoir for m. bovis. however, there is no research on the association between these factors and the status of btb at either fine or large spatial scales. in fact, regional variations in btb eradication strategies through spain are mainly based on the cattle animal/herd prevalence or incidence rates, data obtained from the national programmes for btb eradication. the first contribution of the risk concept to the sanitary strategies appears in the literature only very recently, although there is a lack of inclusion and evaluation of wildlife-related risk factors. moreover, the marked spatial variability in btb risks indicates that we need detailed approaches in particular areas to evaluate different cattle management, environmental and biogeographical factors. characterization of risk factors for tb occurrence are crucial to more cost-effectively allocate financial and personal resources in order to improve the preventive, control and eradication measures in spain and other regions with similar epidemiological conditions. here we focus on an area from south central spain characterized by a complex epidemiological scenario for btb, with the existence of a wildlife-domestic livestock interface under mediterranean conditions and presence of abundant, widely distributed wild ungulate populations where tb is endemic and highly prevalent. in this epidemiological context we used a bayesian model to explore the nature and extent of the association between the distribution of m. bovis infection and potential risk factors in relation to cattle, wild ungulates and environmental aspects. this study is intended to guide policy makers towards risk-based and cost-effective tb eradication strategies.  tb occurrence in ciudad real municipalities was spatially clustered in as indicated by the visual inspection of the spatial distribution of disease and the spatial cluster identified. the model with no predictors had a dic of. the final model that best fitted the data included variables; three of them were statistically significant and positively associated with tb occurrence. the number of sampled animals in the cattle farms included in the sanitary plan in the number of cattle farms with at least one btb-positive animal in the number of tb-positive red deer in and the proportion of cattle farms classified as breeding farms in were marginally statistically significant. the number of farms for bullfighting cattle appeared to improve to final model, although it was not highly significant. the spatial distribution of the variables included in the final model is shown in figure  = quantitative standardized variable;  = dichotomous variable.: significant coefficients of the final model using the 95% ci.: significant coefficients of the final model using the 90% ci. the posterior probability of tb occurrence in ciudad real estimated by the best fitting model resembled the spatial structure of the disease observed in the data, with areas at the highest risk concentrated in the northwest corner, the southwest part and several municipalities in the southern stripe of the region. both si and ui were very low, which may indicate no significant presence in the model of spatial autocorrelation and overdispersion over-and-above the risk factors identified, as well as a good fit of the model. in addition, convergence of the model was obtained after the first iterations and no problems with autocorrelation were identified for the posterior inferences. discussion in this study we aimed to explore the nature and extent of the association between potential risk factors and tb occurrence in wild ungulates and cattle in one of the most tb-prevalent regions of spain referred to as ciudad real. the proportion of cattle farms becoming btb positive in the mean number of hunting seasons in which the hunting estates of the municipality have been inspected and the apparent prevalence of tb in wild boar in were identified as the most relevant factors related to the tb occurrence in in ciudad real. these factors are useful predictors in planning disease control strategies. results revealed that both livestock- and wildlife-related factors determine tb presence at spatial scale. overall, the major risk factor for tb incidence in any given year is whether it was present or not, and at what level, in the previous year. the probability of tb occurrence in ciudad real resembled the biogeography of the province as well as game and cattle farming distribution, with areas at high risk concentrated in the municipalities with a higher proportion of forest or natural habitats, and the highest big game activity. in fact, the mean number of hunting seasons in which the hunting estates of the municipality have been inspected, which is an indicator of the hunting activity in the municipality, remained statistically significant in the model. usually, woodlands and savannah-like areas are dedicated to big game, whereas marginal dehesas are located in the valleys in close proximity, where land is not appropriate for agriculture, are mainly dedicated to extensive livestock farming. this distribution, together with particular mediterranean features that favour the wildlife-livestock interface may explain how tb could be transmitted from wildlife to livestock and vice versa. however, from this study we cannot infer the directionality of m. bovis transmission, i.e. whether wildlife reservoirs are infecting cattle, or whether cattle is the responsible of the circulation of m. bovis in both domestic and wild hosts. in fact, it could be the case that some municipalities with a high prevalence of tb in just one species in may be purely correlated with a high prevalence of tb in only that species the previous year. this would indicate no inter-species transmission in some regions. however, ciudad real municipalities with this scenario are an exception and many tb-infected regions presented tb cases in more than one species. this suggests a potential multi-species interaction scenario. unfortunately, we cannot prove this because the final model did not include any interaction between variables related to hosts. nevertheless, future studies should reveal whether the presence of the disease in wildlife is associated with increased presence of the disease in livestock and establish the directionality and extent of the tb inter-species transmission. the finding that municipalities with a high proportion of cattle farms becoming btb positive in were at high risk for tb occurrence in is an indicator that tb until repeatedly tends to appear in the same municipalities. these findings are in agreement with the trend of incidence and persistence of btb in south central spain during 2006– particularly in ciudad real, observed in previous studies. this indicates the persistence of the pathogen over consecutive sanitary campaigns despite the eradication efforts and the culling of positive animals. herd-level research is needed to elucidate whether barriers imposed to prevent the transmission of m. bovis into btb-free farms are not as efficient as expected, or diagnostics were not reliable enough in presumed free farms. both of these risk factors have not been explored in this study. most of the extensive farms and cattle census in ciudad real province are located in municipalities where some of the risk factors identified in this model may operate, such as wildlife tb reservoir abundance. although the tb inspection in spain is compulsory in all cattle farms, these aspects also show that the efforts in controlling m. bovis infection in the whole cattle stock should not be relaxed, especially in extensive farms where enclosing and handling the whole stock is more difficult. our final model suggests that the higher the number of cattle submitted to the sanitary campaigns, the higher the likelihood of the municipality to be tb positive the following year. as brooks-pollock and keeling reported, many elements associated with herd size could contribute to disease persistence within a herd, such as an increased number of movements or larger land coverage with increased risk of environmental contamination, or more densely stocked cattle. nonetheless, this should be evaluated at the herd level. although the information regarding tb prevalence in wildlife is usually not available and more difficult to obtain than in cattle, we believe that it is also crucial to monitor the tb status of wild reservoirs in a region. in fact, one of the significant covariates in the final model is the mean number of hunting seasons in which the hunting estates of the municipality have been inspected, which is related to the intensity and sustainability of the hunting activity performed in each estate over time, and therefore the abundance of big game. in addition, the analysis revealed two additional major risk factors related to wild hosts: the apparent prevalence of tb in wild boar and the number of tb-positive red deer both in the previous year. the implication of wild boar and red deer in the tb presence and maintenance in south central spain has been previously suggested; the wild boar showing higher tb prevalence than red deer. in addition, wild boar has been proposed as the most relevant wild host of m. bovis in spain becoming a true tb reservoir in the iberian peninsula. this importance is enhanced by its abundance in europe, the high levels of infection observed in this species, its ability to disseminatethe pathogen, its scavenging behaviour and, mostly, its potential ability for crossing fences and contacting with livestock. given this situation, physical biosafety practices may serve as a means to cost-effectively prevent contact between wild and domestic mammals and thus tb inter-species transmission. this is particularly useful in those areas where the hunting industry plays an important role in the local economy, such as ciudad real. also, any action conducted to reduce tb prevalence and mycobacteria spreading in wild ungulates should contribute to reduce the m. bovis transmission risk at the wildlife-livestock interface. options include the management of host density, spatial aggregations at supplementary feeding sites or waterholes, the safe disposal of carrion and viscera by hunters, and oral vaccination. there is evidence supporting the inter-species circulation of m. bovis and several studies have recently confirmed the presence of the same m. bovis spoligotypes in cattle and wild fauna sharing the same area. m. bovis transmission between wild and domestic animals may occur directly via close contact, or indirectly via contamination of food or the environment with m. bovis. most of the btb control programmes in developed countries are mainly directed towards livestock not including wildlife, even where it is obviously involved in disease maintenance. the lack of integral control strategies is more evident in extensive cattle, which is the sector mostly exposed to wildlife contacts. this was supported previously and in our results, since the proportion of cattle farms classified as extensive beef breeding farms and the number of farms devoted to bullfighting cattle were revealed as risk factors in the final model. both types of farms are integrated in natural pasture agrosystems in close proximity with wildlife. however, the inclusion of these two covariates related to extensive cattle farming reinforces the idea that sanitary programs should incorporate the wildlife interface, especially in those cattle farms most exposed to m. bovis infection, as has been done in spain since. the bayesian mixed effects multivariable logistic regression model was chosen as the best statistical approach to be used in this study. the reason is because the bayesian methodology solves most of the problems faced by traditional statistical methods, e.g. the spatial autocorrelation, the potential dependence between the covariates or the incorporation of variables with few observations. the unit of analysis was also considered adequate given the information that was available and the spatial level at which policies are taken. however, as any ecological study, some of the results may be biased as a consequence of the artificial grouping of observations and variables at the municipality level. in addition, differences in the municipality size may confound the interpretation of the maps, since the largest municipalities could appear at the highest risk only because they entail the majority of the observations. although variations in size among municipalities are not particularly large in the study area, we have used proportions in the majority of the covariates to minimize this problem. despite these limitations, the approach used here is very useful for the exploration of spatially aggregated data and to highlight the most risky areas to perform more accurate analysis. the model proposed in this article is robust and consistent, as shown by the much lower dic of the final model and the small sd of si and ui. the robustness and consistence of this model allow to study the “tb hot spots” of the province in detail, since future epidemiological analyses at more local scale may be conducted.  in this study we used a bayesian mixed effects spatial model that controlled for unobserved spatial and non-spatial heterogeneity over-and-above a set of risk factor variables considering environment, wildlife and cattle epidemiological factors. overall, the major risk factor for tb incidence at any given year is whether or not it was present, and at what level, in the previous year. our results support that cattle and big game are both involved in the m. bovis circulation in this region, evidencing a clustered distribution in the western part and an endemicity of the disease in many municipalities. in addition, some characteristics of management and surveillance in this region seem to be linked to tb occurrence. all these findings may guide sanitary authorities to conduct efforts towards specific areas and epidemiological situations where the wildlife-livestock interface seems to critically hamper the definitive success of the btb eradication program. we believe that the inclusion of wild animals in control and eradication programmes, and the development of efficient biosafety practices in extensive farms should be a priority to eradicate the disease in livestock. further studies are needed in order to understand the complex multi-host interaction at the farm level to more precisely evidence directionality of transmission and risks factors associated to tb. 
bovine tuberculosis is a chronic infectious disease mainly caused by mycobacterium bovis. the municipal tb distribution and endemicity was clustered in the western part of the region and clearly overlapped with the explanatory variables identified in the final model: incident cattle farms, number of years of veterinary inspection of big game hunting events, prevalence in wild boar, number of sampled cattle, persistent btb-infected cattle farms, prevalence in red deer, proportion of beef farms, and farms devoted to bullfighting cattle. the spatial distribution of these variables, together with particular mediterranean features that favour the wildlife-livestock interface may explain the m. bovis persistence in this region. sanitary authorities should allocate efforts towards specific areas and epidemiological situations where the wildlife-livestock interface seems to critically hamper the definitive btb eradication success. we used a bayesian mixed effects multivariable logistic regression model to predict tb occurrence in either domestic or wild mammals per municipality in by using information from the previous year. the combination of these eight variables in the final model highlights the importance of the persistence of the infection in the hosts, surveillance efforts and some cattle management choices in the circulation of m. bovis in the region. the aim of this study was to identify the nature and extent of the association between tb distribution and a list of potential risk factors regarding cattle, wild ungulates and environmental aspects in ciudad real, a spanish province with one of the highest tb herd prevalences.
 bovine tuberculosis is a chronic infectious disease mainly caused by mycobacterium bovis. although eradication is a priority for the european authorities, btb remains active or even increasing in many countries, causing significant economic losses. the integral consideration of epidemiological factors is crucial to more cost-effectively allocate control measures. the aim of this study was to identify the nature and extent of the association between tb distribution and a list of potential risk factors regarding cattle, wild ungulates and environmental aspects in ciudad real, a spanish province with one of the highest tb herd prevalences.  we used a bayesian mixed effects multivariable logistic regression model to predict tb occurrence in either domestic or wild mammals per municipality in by using information from the previous year. the municipal tb distribution and endemicity was clustered in the western part of the region and clearly overlapped with the explanatory variables identified in the final model: incident cattle farms, number of years of veterinary inspection of big game hunting events, prevalence in wild boar, number of sampled cattle, persistent btb-infected cattle farms, prevalence in red deer, proportion of beef farms, and farms devoted to bullfighting cattle.  the combination of these eight variables in the final model highlights the importance of the persistence of the infection in the hosts, surveillance efforts and some cattle management choices in the circulation of m. bovis in the region. the spatial distribution of these variables, together with particular mediterranean features that favour the wildlife-livestock interface may explain the m. bovis persistence in this region. sanitary authorities should allocate efforts towards specific areas and epidemiological situations where the wildlife-livestock interface seems to critically hamper the definitive btb eradication success. 