RESUMEN
The members of the Mycobacterium tuberculosis complex (MTC) cause tuberculosis (TB). Infection is transmitted within and between livestock and wildlife populations, thus hampering TB control. Indirect transmission might be facilitated if MTC bacteria persist in the environment long enough to represent a risk of exposure to different species sharing the same habitat. We have, for the first time, addressed the relationship between environmental MTC persistence and the use of water resources in two TB endemic areas in southern Spain with the objective of identifying the presence of environmental MTC and its driving factors at ungulates' water aggregation points. Camera-trap monitoring and MTC diagnosis (using a new MTC complex-specific PCR technique) were carried out at watering sites. Overall, 55.8% of the water points tested positive for MTC in mud samples on the shore, while 8.9% of them were positive in the case of water samples. A higher percentage of MTC-positive samples was found at those waterholes where cachectic animals were identified using camera-trap monitoring, and at the smallest waterholes. Our results help to understand the role of indirect routes of cross-species TB transmission and highlight the importance of certain environmental features in maintaining infection in multihost systems. This will help to better target actions and implement control strategies for TB at the wildlife/livestock interface.
Asunto(s)
Mycobacterium tuberculosis/aislamiento & purificación , Recursos Hídricos , Animales , Técnicas Bacteriológicas/métodos , Bovinos/fisiología , Ciervos/fisiología , Reacción en Cadena de la Polimerasa , España , Sus scrofa/fisiologíaRESUMEN
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).
Asunto(s)
Derrame de Bacterias , ADN Bacteriano/genética , Mycobacterium tuberculosis/genética , Sus scrofa/microbiología , Enfermedades de los Porcinos/microbiología , Animales , Reservorios de Enfermedades , Reacción en Cadena de la Polimerasa , Porcinos , Tuberculosis/microbiología , VacunaciónRESUMEN
We assessed the suitability of targeted removal as a means for tuberculosis (TB) control on an intensely managed Eurasian wild boar (Sus scrofa) hunting estate. The 60km2 large study area included one capture (treatment) site, one control site, and one release site. Each site was fenced. In the summers of 2012, 2013 and 2014, 929 wild boar were live-captured on the treatment site. All wild boar were micro-chipped and tested using an animal side lateral flow test immediately after capture in order to detect antibodies to the Mycobacterium tuberculosis complex (MTC). The wild boar were released according to their TB status: Seropositive individuals onto the release site (hunted after summer), and seronegative individuals back onto the treatment site. The annual summer seroprevalence of antibodies to the MTC declined significantly in live-captured wild boar piglets from the treatment site, from 44% in 2012 to 27% in 2013 (a reduction of 39%). However, no significant further reduction was recorded in 2014, during the third capture season. Fall-winter MTC infection prevalence was calculated on the basis of the culture results obtained for hunter-harvested wild boar. No significant changes between hunting seasons were recorded on either the treatment site or the control site, and prevalence trends over time were similar on both sites. The fall-winter MTC infection prevalence on the release site increased significantly from 40% in 2011-2012 to 64% in 2012-2013 and 2013-2014 (60% increase). Recaptures indicated a persistently high infection pressure. This experiment, the first attempt to control TB in wild boar through targeted removal, failed to reduce TB prevalence when compared to the control site. However, it generated valuable knowledge on infection pressure and on the consequences of translocating TB-infected wild boar.
Asunto(s)
Control de Enfermedades Transmisibles/métodos , Mycobacterium bovis/fisiología , Enfermedades de los Porcinos/prevención & control , Tuberculosis/veterinaria , Animales , Prevalencia , Estudios Seroepidemiológicos , España/epidemiología , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/microbiología , Tuberculosis/epidemiología , Tuberculosis/microbiología , Tuberculosis/prevención & controlRESUMEN
Animal tuberculosis (TB) caused by infection with Mycobacterium bovis and closely related members of the M. tuberculosis complex (MTC), is often reported in the Eurasian wild boar (Sus scrofa). Tests detecting antibodies against MTC antigens are valuable tools for TB monitoring and control in suids. However, only limited knowledge exists on serology test performance in 2-6 month-old piglets. In this age-class, recent infections might cause lower antibody levels and lower test sensitivity. We examined 126 wild boar piglets from a TB-endemic site using 6 antibody detection tests in order to assess test performance. Bacterial culture (n=53) yielded a M. bovis infection prevalence of 33.9%, while serum antibody prevalence estimated by different tests ranged from 19% to 38%, reaching sensitivities between 15.4% and 46.2% for plate ELISAs and between 61.5% and 69.2% for rapid immunochromatographic tests based on dual path platform (DPP) technology. The Cohen kappa coefficient of agreement between DPP WTB (Wildlife TB) assay and culture results was moderate (0.45) and all other serological tests used had poor to fair agreements. This survey revealed the ability of several tests for detecting serum antibodies against the MTC antigens in 2-6 month-old naturally infected wild boar piglets. The best performance was demonstrated for DPP tests. The results confirmed our initial hypothesis of a lower sensitivity of serology for detecting M. bovis-infected piglets, as compared to older wild boar. Certain tests, notably the rapid animal-side tests, can contribute to TB control strategies by enabling the setup of test and cull schemes or improving pre-movement testing. However, sub-optimal test performance in piglets as compared to that in older wild boar should be taken into account.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Mycobacterium bovis/aislamiento & purificación , Enfermedades de los Porcinos/diagnóstico , Prueba de Tuberculina/veterinaria , Tuberculosis/veterinaria , Factores de Edad , Animales , Animales Salvajes , Antígenos Bacterianos/sangre , Femenino , Masculino , Sus scrofa , Porcinos , Enfermedades de los Porcinos/microbiología , Tuberculosis/diagnóstico , Tuberculosis/microbiologíaRESUMEN
Eradication of tuberculosis (TB) in cattle is a priority in the EU. However, and despite the resources invested, TB eradication is still a goal yet to be accomplished. As a consequence, the identification of risk factors contributing to TB transmission and persistence is key to a better understand and, ultimately, more cost-effectively control and eradicate this complex zoonotic disease worldwide. This study aimed to identify the factors contributing to the TB occurrence, new infection, and persistence in one of the most TB-prevalent regions in the South-Central part of Spain (SCS), Ciudad Real (CR), and for which high quality and detailed information on cattle and wild ungulate demographics, management, and sanitary status was available for up to 5 years (2007-2011). Multilevel logistic modeling was used for this purpose. Results of this study revealed that the risk for TB (occurrence, new infection, and/or persistence) in cattle herds from CR is related to TB-persistence on farm in previous years, extensive production systems (beef and bullfighting being more risky that dairy) and large farm in terms of cattle number. Also, the presence and proximity of fenced hunting estates (which are usually intensively managed) significantly contributed to the risk of TB occurrence and persistence in CR. This association suggests that wild ungulates may play a role as TB-reservoirs and transmit TB to cattle in the CR, a region where TB is endemic and is associated with extensive farming of beef cattle. To the best of author's knowledge this is the first study to (i) evaluate the wild ungulate-domestic interface at a farm level using detailed information over an extensive region and period of time (2007-2011) and (ii) to identify a direct association between TB in cattle and the proximity and management practices of wild ungulates. Methods and results presented here may support policies to better prevent and control TB in the SCS and in other regions/countries with similar epidemiological conditions.
Asunto(s)
Tuberculosis Bovina/epidemiología , Tuberculosis Bovina/transmisión , Crianza de Animales Domésticos , Animales , Bovinos , Incidencia , Modelos Logísticos , Modelos Biológicos , Prevalencia , Factores de Riesgo , España/epidemiología , Tuberculosis Bovina/microbiologíaRESUMEN
Tuberculosis (TB), a chronic disease caused by infection with the Mycobacterium tuberculosis complex, is endemic in wild boar (Sus scrofa) and red deer (Cervus elaphus) in south-central Spain. Understanding the temporal dynamics of this chronic infection requires long time series data collection over large areas. The aim of this paper was to identify the determinants of TB prevalence and severity in both species in Ciudad Real province, Spain, from 2000 to 2012. Study variables included management, population dynamics, and a range of geographical and climatological factors. The prevalence of TB in wild boar increased from 50% to 63% since the study commenced. This may be due to an increased hunting bag (a proxy for population abundance), which was correlated with TB infection rates. Low rainfall (a stochastic factor) was associated with higher individual risk of TB presence and progression, resulting in an increased proportion of severe cases of wild boar TB in dry years. This was probably a result of increased food restriction leading to a higher susceptibility to TB. In contrast, red deer TB showed an apparent stable trend, which may be a consequence of the species' higher and stable population size. Hunting management, characterized by fencing, was associated with a higher risk of TB in both wild boar and red deer, suggesting that intensive hunting management may have contributed to exacerbated TB figures. This difference was more marked in red deer than in wild boar, probably because fencing imposes less restriction on movement, population mixing and TB spread to wild boar than to deer. Our findings on TB dynamics are fundamental for assessing the impact of future disease-control actions (e.g. field vaccination). Moreover, such control plans must operate in the long term and cover large areas.
Asunto(s)
Animales Salvajes/microbiología , Reservorios de Enfermedades/microbiología , Reservorios de Enfermedades/veterinaria , Tuberculosis/epidemiología , Tuberculosis/veterinaria , Animales , Control de Enfermedades Transmisibles/métodos , Ciervos/microbiología , Femenino , Masculino , Región Mediterránea/epidemiología , Mycobacterium/aislamiento & purificación , Densidad de Población , Prevalencia , Factores de Riesgo , España/epidemiología , Sus scrofa/microbiologíaRESUMEN
The diversification of livestock farms into hunting estates in South Central Spain (SCS) may impede the success of Mycobacterium bovis eradication programmes by facilitating transmission between wildlife and livestock. In this observational study we aimed to provide information of relevance about the nature and frequency of interactions (observed visits to study points) between livestock (cattle and domestic pigs) and wildlife (wild boar and red deer). The study was conducted in an extensive cattle farm in SCS where the land is also used for game hunting. During a period of one year, camera traps (n=16) were placed at a priori risk points for interspecies interactions: water (natural and artificial troughs), food placed on the ground for baiting wildlife, and pasture. To define indirect interspecies interactions, a critical time window for M. bovis to survive in the environment was selected based on the literature. Results suggest that wildlife frequented food and pasture points more often than water points, and that the number of visits increased through the dry season, peaking during the acorn season (October-January) and the deer breeding season (June-July). Direct interactions were rare (n=10), as opposed to indirect interactions (n=8992). Wildlife-followed-by-livestock interactions (n=7714) occurred much more often than livestock-followed-by-wildlife (n=1278) and were frequent at water points (66% water points, 17% food, 17% pasture). Results also suggest that water points are a hotspot for indirect interactions and might therefore be a source of infection at the wildlife-livestock interface in the territory covered, particularly for M. bovis, as it is around water where the bacteria seem to survive the longest. Preventing aggregation and therefore reducing contact rates between domestic and wild animals especially at water points may be valuable for disease control in South Central Spain.
Asunto(s)
Animales Salvajes/fisiología , Conservación de los Recursos Naturales , Ganado/fisiología , Actividad Motora , Animales , Bovinos/fisiología , Ciervos/fisiología , Ambiente , Mycobacterium bovis/fisiología , Fotograbar/veterinaria , España , Porcinos/fisiología , Tuberculosis/transmisión , Tuberculosis/veterinariaRESUMEN
Tuberculosis (TB) is endemic in Eurasian wild boar (Sus scrofa) and red deer (Cervus elaphus) in south central Spain, where evidence suggests transmission to domestic cattle. Known risk factors for TB at the interface between livestock and wild ungulate species include density and spatial overlap, particularly around waterholes during summer. We evaluated the effectiveness of selective exclusion measures for reducing direct and indirect interaction between extensive beef cattle and wild ungulates at waterholes as an alternative for the integrated control of TB. We first monitored 6 water points (WP) with infrared-triggered cameras at a TB positive cattle farm to quantify interactions. We then assigned 3 WP to be "cattle-only" and 3 to be "wildlife-only". Cattle-only WP were surrounded with a wildlife-proof fence (2.5 m high) and an original design of cattle-specific gate. Wildlife-only WP were surrounded by a fence that wild ungulates could breach but cattle could not (1.2 m high). Red deer, roe deer (Capreolus capreolus) and wild boar easily jumped or undercrossed this fence. Wildlife-only fences were 100% effective in preventing cattle access to WP and did not impede wildlife use. Many cows learned to operate the cattle-specific gate quickly and others followed and learned from them. Within 2 weeks, around 70% of cows actively entered and exited through the cattle-specific gate. We demonstrate how simple, low-cost fencing strategies can serve as biosecurity measures to substantially reduce direct and indirect contact between cattle and wild ungulates, serving to reduce the potential for TB transmission. Our designs can be used in the context of integral plans to mitigate disease transmission between cattle and wildlife, and have potential for protecting or segregating the use of a variety of resources in different contexts.
Asunto(s)
Crianza de Animales Domésticos/métodos , Bovinos/fisiología , Ciervos/fisiología , Reservorios de Enfermedades/veterinaria , Sus scrofa/fisiología , Tuberculosis Bovina/prevención & control , Tuberculosis Bovina/transmisión , Animales , Reservorios de Enfermedades/microbiología , Actividad Motora , Mycobacterium bovis/fisiología , España/epidemiología , Tuberculosis Bovina/epidemiología , Tuberculosis Bovina/microbiologíaRESUMEN
In south-central Spain, the harvest of Eurasian wild boar (Sus scrofa) has increased significantly during recent decades in association with more intensive management actions to increase hunting yields and with consequent effects on the health status of the wild boar populations. We investigated the spatio-temporal trends and the risk factors related to the prevalence of Trichinella spp. in wild boar in order to obtain the annual probability of occurrence for these parasites in the Ciudad Real province of south-central Spain. Based on muscle samples collected during the hunting seasons from 1998/1999 to 2009/2010, the mean prevalence for Trichinella spp. in 95,070 wild boar was 0.2% (95% confidence interval 0.17-0.23). A subsample of 1,432 wild boar was also tested by ELISA. No correlation was observed between the prevalence of infection detected by serology and by the artificial digestion of muscle. The presence of Trichinella infections in wild boar showed a decreasing trend during the study period and was negatively related with fenced wild boar populations. The predicted 'favourability' for Trichinella infections disappeared almost completely after the 2006/2007 hunting season. Risk maps based on biogeographical tools showed, however, that most hunting estates presented favourable risk factors for these parasites during at least one of the hunting seasons studied.
Asunto(s)
Enfermedades de los Porcinos/parasitología , Trichinella/aislamiento & purificación , Triquinelosis/veterinaria , Animales , Animales Salvajes/inmunología , Animales Salvajes/parasitología , Anticuerpos Antihelmínticos/inmunología , Ensayo de Inmunoadsorción Enzimática , Prevalencia , Factores de Riesgo , España/epidemiología , Sus scrofa , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/inmunología , Trichinella/clasificación , Trichinella/inmunología , Triquinelosis/epidemiología , Triquinelosis/inmunología , Triquinelosis/parasitologíaRESUMEN
Fallow deer (Dama dama) are widely distributed as natural or naturalised populations, as well as in game parks and deer farms. We used 157 fallow deer sampled in populations considered to be Mycobacterium tuberculosis complex (MTC) free and 73 Mycobacterium bovis-infected fallow deer confirmed postmortem by culture to evaluate the diagnostic performance of two tests for the detection of anti-mycobacterial antibodies: the dual path platform (DPP) VetTB assay and the bovine purified protein derivative (bPPD) ELISA. We also compared their sensitivity with that of the skin test, analyzed the effect of haemolysis degree on the antibody detection and described the relationship between the test readings and presence/absence of gross tuberculosis (TB) compatible lesions. Sensitivity of bPPD ELISA was 51% at a specificity of 96%. Depending on the cut-off value selected, the sensitivity of DPP VetTB ranged from 62 to 71%, while its specificity was 88-95%. In the subgroup of M. bovis-infected deer for which the skin test data were available (33 of 73); this method detected 76% of culture-positive animals, although the specificity of the intradermal test was not determined in this study. When the DPP VetTB and skin test data were combined, the resulting sensitivity obtained in this sub-group of M. bovis-infected deer increased to 97%. Gross pathology identified TB compatible lesions (TBL) in 89% culture-confirmed fallow deer. The infected animals with visible lesions had significantly higher readings in the DPP VetTB, but not in the bPPD ELISA. Only high levels of haemolysis decreased antibody test sensitivity and this effect was more evident for the bPPD ELISA. The results allowed inferring a number of management recommendations for rapid detection of MTC infection in live fallow deer and in surveys on hunter-harvested cervids.