Trap-effectiveness and response to tiletamine-zolazepam and medetomidine anaesthesia in Eurasian wild boar captured with cage and corral traps

Capture, handling and chemical restraint are basic techniques often needed for research or management purposes. The aim of this study was testing a combination of tiletamine-zolazepam (TZ) (3 mg/kg) and medetomidine (M) (0.05 mg/kg) on Eurasian wild boar (Sus scrofa). A total of 77 free-ranging wild boar were captured by means of portable cages and corral traps and then anaesthetized with intramuscular darts using a blowpipe. The individual response to chemical immobilization was characterized using anaesthetic, clinical, and serum biochemical variables. After the procedure, 14 of these wild boar were monitored for 20 days using GPS-GSM collars

Host Richness Increases Tuberculosis Disease Risk in Game-Managed Areas

Current scientific debate addresses whether species richness in animal communities may negatively moderate pathogen transmission and disease outcome (dilution effect), or to the contrary, if disease emergence benefits from more diverse community assemblages (amplification effect). The result may not depend exclusively on patterns of host species biodiversity but may depend on the specific composition of reservoir hosts and vectors, and their ecology. Host–pathogen interactions have shaped variations in parasite virulence, transmissibility and specificity. In the same way the importance of factors related to host exposure or to life history trade-offs are expected to vary. In this study, we demonstrate that ungulate host species richness correlates with increased community competence to maintain and transmit pathogens of the Mycobacterium tuberculosis complex (MTC) in game-managed areas in Mediterranean Spain. Therefore, we should consider natural and artificial variations in life histories of pathogens and host communities to characterize the impact of biodiversity on the health of diverse assemblages of human and animal communities. Since most approaches assessing epidemiology and transmission of shared pathogens only involve single- or pair-species, further research is needed to better understand the infection dynamics from complete community assemblages, at least in chronic diseases such as tuberculosis and in non-natural animal communities

A Bayesian approach to study the risk variables for tuberculosis occurrence in domestic and wild ungulates in South Central Spain

Background: Bovine tuberculosis (bTB) 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. Results: We used a Bayesian mixed effects multivariable logistic regression model to predict TB occurrence in either domestic or wild mammals per municipality in 2007 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: (1) incident cattle farms, (2) number of years of veterinary inspection of big game hunting events, (3) prevalence in wild boar, (4) number of sampled cattle, (5) persistent bTB-infected cattle farms, (6) prevalence in red deer, (7) proportion of beef farms, and (8) farms devoted to bullfighting cattle. Conclusions: 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

Evaluation of the clinical evolution and transmission of SARS-CoV-2 infection in cats by simulating natural routes of infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the current pandemic disease denominated as Coronavirus Disease 2019 (COVID-19). Several studies suggest that the original source of this virus was a spillover from an animal reservoir and its subsequent adaptation to humans. Of all the different animals affected, cats are one of the most susceptible species. Moreover, several cases of natural infection in domestic and stray cats have been reported in the last few months. Although experimental infection assays have demonstrated that cats are successfully infected and can transmit the virus to other cats by aerosol, the conditions used for these experiments have not been specified in terms of ventilation. We have, therefore, evaluated the susceptibility of cats using routes of infection similar to those expected under natural conditions (exposure to a sneeze, cough, or contaminated environment) by aerosol and oral infection. We have also evaluated the transmission capacity among infected and naïve cats using different air exchange levels. Despite being infected using natural routes and shed virus for a long period, the cats did not transmit the virus to contact cats when air renovation features were employed. The infected animals also developed gross and histological lesions in several organs. These outcomes confirm that cats are at risk of infection when exposed to infected people, but do not transmit the virus to other cats with high rates of air renovation

Adenovirus-vectored African Swine Fever Virus Antigens Cocktail Is Not Protective against Virulent Arm07 Isolate in Eurasian Wild Boar

African swine fever (ASF) is a viral disease of domestic and wild suids for which there is currently no vaccine or treatment available. The recent spread of ASF virus (ASFV) through Europe and Asia is causing enormous economic and animal losses. Unfortunately, the measures taken so far are insufficient and an effective vaccine against ASFV needs to be urgently developed. We hypothesized that immunization with a cocktail of thirty-five rationally selected antigens would improve the protective efficacy of subunit vaccine prototypes given that the combination of fewer immunogenic antigens (between 2 and 22) has failed to elicit protective efficacy. To this end, immunogenicity and efficacy of thirty-five adenovirus-vectored ASFV antigens were evaluated in wild boar. The treated animals were divided into different groups to test the use of BioMize adjuvant and different inoculation strategies. Forty-eight days after priming, the nine treated and two control wild boar were challenged with the virulent ASFV Arm07 isolate. All animals showed clinical signs and pathological findings consistent with ASF. This lack of protection is in line with other studies with subunit vaccine prototypes, demonstrating that there is still much room for improvement to obtain an effective subunit ASFV vaccine

Host and environmental factors modulate the exposure of free-ranging and farmed red deer (Cervus elaphus) to coxiella burnetii

The control of multihost pathogens, such as Coxiella burnetii, should rely on accurate information about the roles played by the main hosts. We aimed to determine the involvement of the red deer (Cervus elaphus) in the ecology of C. burnetii. We predicted that red deer populations from broad geographic areas within a European context would be exposed to C. burnetii, and therefore, we hypothesized that a series of factors would modulate the exposure of red deer to C. burnetii. To test this hypothesis, we designed a retrospective survey of 47 Iberian red deer populations from which 1,751 serum samples and 489 spleen samples were collected. Sera were analyzed by enzyme-linked immunosorbent assays (ELISA) in order to estimate exposure to C. burnetii, and spleen samples were analyzed by PCR in order to estimate the prevalence of systemic infections. Thereafter, we gathered 23 variables— within environmental, host, and management factors—potentially modulating the risk of exposure of deer to C. burnetii, and we performed multivariate statistical analyses to identify the main risk factors. Twenty-three populations were seropositive (48.9%), and C. burnetii DNA in the spleen was detected in 50% of the populations analyzed. The statistical analyses reflect the complexity of C. burnetii ecology and suggest that although red deer may maintain the circulation of C. burnetii without third species, the most frequent scenario probably includes other wild and domestic host species. These findings, taken together with previous evidence of C. burnetii shedding by naturally infected red deer, point at this wild ungulate as a true reservoir for C. burnetii and an important node in the life cycle of C. burnetii, at least in the Iberian Peninsula

Epidemiología y prevención en la interacción sanitaria entre ungulados domésticos y silvestres.

Esta Tesis Doctoral aborda el estudio de la interacción entre los ungulados silvestres y el ganado en el suroeste de la Península Ibérica, tomando la tuberculosis (TB) como modelo de enfermedad. Los aspectos sanitarios relacionados con la interacción se han investigado desde una perspectiva multidisciplinar, donde se han combinado aportaciones del campo de la ecología hospedador-patógeno-ambiente, epidemiologia, patología y genética, usando las tecnologías más innovadoras. Esta Tesis Doctoral pretende mejorar el conocimiento de los factores de riesgo que determinan el mantenimiento o re-emergencia de la infección asociados a la interacción doméstico- silvestre, así como identificar posibles medidas de prevención en ambientes mediterráneos. A lo largo de la introducción se revisa la información actual sobre la interfaz sanitaria entre la fauna silvestre y el ganado, así como la situación epidemiológica, riesgo de re-emergencia y opciones de control de la TB en ambientes mediterráneos. Contenido de la investigación El primer capítulo de esta Tesis Doctoral caracteriza la situación epidemiológica de la TB y su tendencia temporal en las poblaciones de ungulados silvestres y domésticos mediante dos estudios: Capítulo 1.1. Efecto de la diversidad de hospedadores sobre el riesgo de detectar tuberculosis. Capítulo 1.2. Tendencia temporal de la tuberculosis en ungulados silvestres de la España mediterránea. El segundo capítulo describe los patrones espacio-temporales de uso del hábitat de los hospedadores silvestres y domésticos que determinan la interacción entre ambos grupos, que ha sido abordado mediante dos estudios: Capítulo 2.1. Uso de aviones no tripulados para estudiar la abundancia de ungulados: importancia en la epidemiología espacial. Capítulo 2.2. Interacciones espacio-temporales entre jabalí y ganado: implicaciones en la transmisión de la infección. El tercer capítulo identifica los factores determinantes de la excreción por el jabalí y presencia ambiental del complejo Mycobacterium tuberculosis en puntos de interacción con el ganado: Capítulo 3.1. Vías de excreción del complejo Mycobacterium tuberculosis por el principal reservorio de la Península Ibérica, el jabalí. Capítulo 3.2. Presencia del complejo Mycobacterium tuberculosis en puntos de agregación de ungulados silvestres y ganado. El cuarto y último capítulo aborda la prevención sanitaria de la interacción con el fin de encontrar medidas para disminuir las tasas de contacto directas e indirectas en puntos de agregación. Capítulo 4.1. Efectividad de las barreras selectivas de exclusión en la prevención sanitaria de la interacción multi-hospedador. Conclusiones 1. Los sistemas ecológicos y epidemiológicos complejos, en términos de diversidad de hospedadores propios de la gestión ganadera extensiva y cinegética del centro y sur de la Península Ibérica, favorecen la capacidad de dichos sistemas para mantener la tuberculosis (TB). En este contexto, se rechaza la hipótesis del ¿efecto de dilución¿ en la transmisión del complejo Mycobacterium tuberculosis (CMT) entre múltiples hospedadores. 2. En la provincia de Ciudad Real se evidencia una tendencia temporal creciente en la prevalencia de TB en el jabalí: aumenta un 30% en 12 años alcanzando una prevalencia del 63% al final del periodo estudiado. Dicha prevalencia es posiblemente modulada por factores de gestión, demográficos y climáticos. En cambio, la prevalencia de TB en el ciervo es aparentemente estable, propia de situaciones endémicas estabilizadas. ¿ 3. El uso de imágenes de alta resolución obtenidas por aviones no tripulados y el seguimiento posicional simultáneo por collares GPS, en combinación con herramientas de análisis espaciales, permiten determinar los patrones de distribución, abundancia e interacción de la comunidad de hospedadores. Esta información es de gran utilidad para el estudio de los factores de riesgo que modulan la trasmisión y persistencia de infecciones compartidas, como la TB, a detalladas escalas espaciales. 4. El solapamiento espacial inter-específico es estacionalmente mayor en determinados hábitats del Parque Nacional de Doñana. Particularmente, el uso compartido de los recursos hídricos permanentes provoca marcadas interacciones espacio-temporales entre bovino y ungulados silvestres, especialmente durante la estación seca. Estos puntos de agua actúan como potenciales focos de transmisión de CMT en ambientes mediterráneos. 5. Se describen tres vías potenciales de excreción (nasal, oral y fecal) de CMT en jabalíes naturalmente infectados del centro y sur de la Península Ibérica. Se han hallado frecuencias de detección de ADN de CMT (30%) mayores que en cualquier otro reservorio silvestre de TB estudiado. 6. La detección frecuente de ADN específico de CMT en recursos hídricos permanentes, escasos en la estación seca, sugiere que la interacción entre ungulados silvestres y domésticos en estos puntos de riesgo es un factor clave para el mantenimiento de la TB. Nuestros resultados sugieren que la transmisión inter- específica de CMT por vía indirecta es más frecuente que la vía de transmisión directa. 7. Determinadas medidas de bioseguridad, como los vallados selectivos y la gestión de los puntos del agua, son capaces de reducir la interacción entre hospedadores silvestres y domésticos, y son potencialmente adecuadas como herramienta dentro del control integrado de las infecciones compartidas

A proposal to consider animal health aspects in the regulation of game management

Las especies cinegéticas comparten infecciones con el hombre, los animales domésticos y el resto de la fauna silvestre que pueden afectar seriamente a la salud pública, la sanidad animal, la conservación y la producción cinegética; de ahí su relevancia. Pese a ello, la sanidad de las especies cinegéticas apenas es tenida en cuenta en los planes de gestión de estas especies. En este texto enumeramos las principales debilidades de la gestión cinegética desde el punto de vista sanitario: (1) la no aplicación de la legislación sobre control sanitario en traslados y repoblaciones; (2) la indefinición del estatus de las granjas cinegéticas; (3) la ausencia de un registro de “cercones” y la ilegalidad de los mismos; (4) la falta de clasificación correcta de los terrenos cinegéticos; (5) el seguimiento inadecuado del tamaño de las poblaciones y sus efectos sobre el medio; (6) la falta de regulación del aporte artificial de alimento; (7) la falta de consideración de los riesgos sanitarios derivados de la sobreabundancia; (8) los conflictos por la gestión de residuos de caza; (9) la deficiente inspección sanitaria de los animales cazados; (10) la no regulación de los tratamientos farmacológicos en especies cinegéticas y (11) la falta de intercambio de información dentro de la administración y la necesidad de valoración y aprobación del plan técnico de caza por la autoridad de sanidad animal. Para cada una de ellas, proponemos cambios en la regulación de la actividad cinegética, basándonos en ejemplos españoles y en la literatura científica internacional.Game species share diseases with humans, livestock and wildlife, hence their relevance. However, game species health is not considered in current Spanish hunting management regulation. This paper lists the main weaknesses of game management from the sanitary point of view: (1) insufficient enforcement of current animal health and movement regulations, (2) lack of a clear definition and classification of game farms, (3) uncertain status of interior wild boar fences or “cercones”, (4) lack of a proper classification of the hunting estates, (5) inadequate wildlife population monitoring, (6) lack of regulation on artificial feeding, (7) health risks associated to overabundance; (8) big game waste conflicts (9) poor veterinary inspection of hunted animals (10), lack of regulation of pharmaceutical treatments on game species, and (11) poor information flow within the administration departments. For each point, we propose changes to the hunting regulation, based on Spanish and international scientific literature

Computer Vision Applied to Detect Lethargy through Animal Motion Monitoring: A Trial on African Swine Fever in Wild Boar

Early detection of infectious diseases is the most cost-effective strategy in disease surveillance for reducing the risk of outbreaks. Latest deep learning and computer vision improvements are powerful tools that potentially open up a new field of research in epidemiology and disease control. These techniques were used here to develop an algorithm aimed to track and compute animal motion in real time. This algorithm was used in experimental trials in order to assess African swine fever (ASF) infection course in Eurasian wild boar. Overall, the outcomes showed negative correlation between motion reduction and fever caused by ASF infection. In addition, infected animals computed significant lower movements compared to uninfected animals. The obtained results suggest that a motion monitoring system based on artificial vision may be used in indoors to trigger suspicions of fever. It would help farmers and animal health services to detect early clinical signs compatible with infectious diseases. This technology shows a promising non-intrusive, economic and real time solution in the livestock industry with especial interest in ASF, considering the current concern in the world pig industry

DNA Detection Reveals Mycobacterium tuberculosis Complex Shedding Routes in Its Wildlife Reservoir the Eurasian Wild Boar

Since the intensity and frequency of pathogen shedding by hosts determine the probability of infection through direct and indirect contact, the shedding characterization of Mycobacterium tuberculosis complex (MTC) in the key host reservoir in Iberia, the Eurasian wild boar (Sus scrofa), is crucial. We aimed (i) to describe the natural shedding routes of MTC in free-ranging wild boar by a new semi-automated PCR method and (ii) to determine the association of MTC shedding pattern with tuberculosis (TB) progression and individual factors. MTC shedding (by any of the possible routes) was detected in a total of 30.8% (±7.5) out of the sampled individuals with valid or interpretable test results (n = 39). The proportion of TB-positive shedders according to the route was 13.6% (±7.5) for oral swabs, 4.5% (±4.5) for nasal swabs, 4.5% (±4.4) for faecal swabs and 13.6% (±7.5) for individuals being positive to all swabs concomitantly. The probability of shedding mycobacteria (by any route) statistically associated with TB generalization, and the TB score was significantly higher in individuals testing positive to at least one route compared to negatives. Overall, a diversity of shedding routes in wild boar is possible, and it is remarkable that for the first time, the faecal shedding is confirmed for naturally infected wild boar. Our results are consistent with the role wild boar plays for TB maintenance in host communities and environments in Iberia and confirm that it is an important source of mycobacteria infection by different routes. Finally, we evidenced the use of a new PCR technique to detect MTC DNA in excretions can be practical and defined the target routes for sampling wild boar shedding in future studies, such as interventions to control TB in wild boar that can be measured in terms of impact on mycobacteria excretion and transmission (i.e. vaccination).Depto. de Sanidad AnimalFac. de VeterinariaTRUEpu