The Life Cycle of Toxoplasma gondii in the Natural Environment

Chapitre 1International audienc

Bovine tuberculosis in wildlife in France. Risk for cattle

Tuberculosis (TB) due to M. bovis has been described in wildlife species of many countries, albeit, depending on the situation, being considered as a sentinel or a reservoir of the infection for livestock and/or human. In France, TB has been discovered for the first time, in 2001, in wild ungulates of the Brotonne Forest (Normandy). Since then, passive and active surveillance for the disease has been implemented in several regions, and later expanded to the whole country through the Sylvatub surveillance program since 2011. Firstly described in wild boar and red deer, it has also been detected in 2009 in badgers of Côte d’Or, then in 2010 in Dordogne and Charente. The presence of high density populations of wild animals and some practices as artificial feeding, which lead to non-natural high concentrations of animals, are major factors of emergence and persistence of TB in wildlife. In several French regions, M. bovis would be circulating in a multi-host system including bovines (and pigs, in Corsica only), several wildlife species and their environment which thus complicates the epidemiology and sanitary management of the diseaseLa tuberculose à Mycobacterium bovis (TB) est décrite dans la faune sauvage de plusieurs pays, celle-ci pouvant être, selon les cas, sentinelle ou réservoir de l’infection pour les bovins et/ou l’homme. En France, la TB a été découverte en 2001 chez des ongulés sauvages en forêt de Brotonne (Normandie). Depuis cette date, une surveillance événementielle et programmée de la maladie a été mise en place dans plusieurs départements, puis étendue de façon harmonisée à tout le territoire français métropolitain grâce à la mise en place du dispositif Sylvatub depuis 2011. D’abord décrite chez les cerfs et les sangliers, la TB a été détectée chez le blaireau en 2009 en Côte d’Or, puis en 2010 en Dordogne et en Charente. La présence de fortes densités d’animaux sauvages et entre autres la pratique de l’agrainage, qui provoque des concentrations artificielles d’animaux, sont des facteurs majeurs d’émergence et de persistance de la TB dans les populations sauvages. Dans plusieurs régions de France, M. bovis semble circuler dans un système multi-hôtes comprenant les bovins (et les porcs en Corse uniquement), plusieurs espèces sauvages et leur environnement ce qui complique l’épidémiologie et la gestion sanitaire de la maladi

Quantification of the animal tuberculosis multi-host community offers insights for control

Animal tuberculosis (TB) is a multi-host zoonotic disease whose prevalence in cattle herds in Europe has been increasing, despite a huge investment in eradication. The composition of the host community is a fundamental driver of pathogen transmission, and yet this has not been formally quantified for animal TB in Europe. We quantified multi-host communities of animal TB, using stochastic models to estimate the number of infected domestic and wild hosts in three regions: officially TB-free Central–Western Europe, and two largely TB-endemic regions, the Iberian Peninsula and Britain and Ireland. We show that the estimated number of infected animals in the three regions was 290,059–1,605,612 and the numbers of infected non-bovine domestic and wild hosts always exceeded those of infected cattle, with ratios ranging from 3.3 (1.3–19.6):1 in Britain and Ireland to 84.3 (20.5–864):1 in the Iberian Peninsula. Our results illustrate for the first time the extent to which animal TB systems in some regions of Europe are dominated by non-bovine domestic and wild species. These findings highlight the need to adapt current strategies for effective future control of the disease.This research was funded by MINECO and EU-FEDER WildDriver grant CGL2017-89866; NS was funded by FCT—Fundação para a Ciência e a Tecnologia grant SFRH/BPD/116596/2016

Experimental Infection of Captive Red Foxes (Vulpes vulpes) with Mycobacterium bovis

[EN] In Europe, animal tuberculosis (TB) due to Mycobacterium bovis involves multi-host communities that include cattle and wildlife species, such as wild boar (Sus scrofa), badgers (Meles meles) and red deer (Cervus elaphus). Red fox (Vulpes vulpes) infections have also been recently reported in some TB endemic regions in the Iberian Peninsula and France, with some of the infected animals shedding M. bovis in urine and feces. In order to understand the pathogenesis of M. bovis infection in foxes and the associated risk of transmission, 12 captive foxes (6 females and 6 males) were inoc-ulated orally with 2 × 107 colony-forming units of a French field isolate of M. bovis. Clinical samples (urine, feces and oropharyngeal swabs) were collected every four weeks and tested for molecular diagnosis and bacteriology. Serological responses were measured by IDEXX M. bovis Ab Test and Multi Antigen Print Immunoassay (MAPIA). At a post-mortem examination performed 12 weeks post infection (wpi), tissues were tested for the presence of M. bovis and associated gross and microscopic TB-like lesions. M. bovis was detected by PCR in bladder swabs of 3 animals at 12 wpi. It was also detected pre-mortem at different time points of the experiment in the oropharyngeal mu-cus of three individuals and in the feces of nine foxes, with two of them confirmed by bacteriology. All 12 foxes had at least 4 PCR positive samples (out of the 23 tested), and all but 1 fox had at least 1 culture positive sample. The culture negative fox was PCR positive in both retropharyngeal and mesenteric lymph nodes, in line with the results of the other animals. Seroconversion was observed in all foxes except one during the experiment, and in nine at the final time point. No gross visible lesions were found in any animal at the post-mortem examination. The histology showed small granulomas within the lymph nodes, tonsils, liver and lungs from eight animals, with the presence of few acid-fast bacilli. These results confirmed that all orally-infected foxes developed mild TB lesions but they were able to shed mycobacteria in about 75% of cases, 1 month post-infection (9 out 12 foxes). These results show that it is possible to induce typical TB infection experimentally in captive foxes, with measurable M. bovis excretion; such an experimental system could be useful for future evaluations of diagnostics and vaccines in this speciesSIThe French Ministry of Agriculture mainly financed the sampling and the analyses in the framework of the RFSA call on TB projects (Anses-DGAl credit agreement RFSA 2017-326). The animals and the running cost of the BSL3 facilities and technical resources were financed by the European Commission in the context of Horizon 2020?Vetbionet Transnational Access Activities (TNA) call. This work is also partially the result of the I+D+i research project RTI2018-096010-B-C21, funded by the Spanish MCIN/AEI/10.13039/501100011033/ Ministry of Science, Innovation and the European Regional Development Funds (FEDER Una manera de hacer Europa), and of PCTI 2021? 2023 (GRUPIN: IDI2021-000102) funded by Principado de Asturias and FEDE

Infection of Wildlife by Mycobacterium bovis in France Assessment Through a National Surveillance System, Sylvatub

Mycobacterium bovis infection was first described in free-ranging wildlife in France in 2001, with subsequent detection in hunter-harvested ungulates and badgers in areas where outbreaks of bovine tuberculosis (TB) were also detected in cattle. Increasing concerns regarding TB in wildlife led the French General Directorate for Food (DGAL) and the main institutions involved in animal health and wildlife management, to establish a national surveillance system for TB in free-ranging wildlife. This surveillance system is known as “Sylvatub.” The system coordinates the activities of various national and local partners. The main goal of Sylvatub is to detect and monitor M. bovis infection in wildlife through a combination of passive and active surveillance protocols adapted to the estimated risk level in each area of the country. Event-base surveillance relies on M. bovis identification (molecular detection) (i) in gross lesions detected in hunter-harvested ungulates, (ii) in ungulates that are found dead or dying, and (iii) in road-killed badgers. Additional targeted surveillance in badgers, wild boars and red deer is implemented on samples from trapped or hunted animals in at-risk areas. With the exception of one unexplained case in a wild boar, M. bovis infection in free-living wildlife has always been detected in the vicinity of cattle TB outbreaks with the same genotype of the infectious M. bovis strains. Since 2012, M. bovis was actively monitored in these infected areas and detected mainly in badgers and wild boars with apparent infection rates of 4.57–5.14% and 2.37–3.04%, respectively depending of the diagnostic test used (culture or PCR), the period and according to areas. Sporadic infection has also been detected in red deer and roe deer. This surveillance has demonstrated that M. bovis infection, in different areas of France, involves a multi-host system including cattle and wildlife. However, infection rates are lower than those observed in badgers in the United Kingdom or in wild boars in Spain

Utilisation d'un outil sérologique pour estimer l'exposition des Sangliers à M. Bovis

et al.[FR]: Le sanglier (Sus scrofa) est de plus en plus considéré comme un acteur important à prendre en compte dans l'épidémiologie de la tuberculose bovine (TB); le suivi de la TB chez cette espèce revêt alors un enjeu important pour établir des programmes globaux de lutte contre cette maladie. Afin d’estimer en France l'exposition des sangliers sauvages au complexe Mycobacterium tuberculosis (MTC), un ELISA fondé sur un dérivé de protéine bovine purifiée (PPD) a été utilisé pour tester une sérothèque de 2 080 échantillons provenant d’animaux prélevés à la chasse dans 58 départements entre 2000 et 2010. Deux valeurs seuils ont été utilisées pour l'interprétation diagnostique : le seuil de 0,2, recommandé par le fabricant (spécificité: 96,4 %; sensibilité: 72,6%) et le seuil de 0,5 (spécificité: 100%; sensibilité: 65%). Une bonne cohérence spatio‐temporelle entre les sangliers séropositifs et les foyers de TB chez les bovins est mise en évidence, en particulier à la valeur seuil de 0,5 (la distance moyenne entre un foyer bovin et les sangliers séropositifs les plus proches étant de 13 km). Au delà de permettre une première description de la séroprévalence globale et de la répartition géographique de l’exposition au MTC des sangliers en France, nos résultats suggèrent que le test ELISA peut être utilisé à une échelle populationnelle comme un premier outil de surveillance de la TB chez les sangliers, suivi d’éventuelles investigations complémentaires combinant examens lésionnels et culture.[EN]: The Eurasian wild boar (Sus scrofa) is increasingly considered as a significant actor in the epidemiology of animal tuberculosis (TB). Therefore, monitoring TB in wild boar becomes a key tool in the development of comprehensive control schemes for this disease. To estimate the exposure of free living wild boars to the Mycobacterium tuberculosis complex (MTC) in France, a bovine‐purified protein derivative (PPD) based ELISA was used to test 2,080 archived serum samples from hunter‐harvested animals in 58 French “départements”. Two cut‐off values were used for diagnostic interpretation: 0.2, recommended by the manufacturer (specificity: 96.4%; sensitivity: 72.6%), and 0.5 (specificity: 100%; sensitivity: 64%). A good consistence between seropositive wild boar and TB outbreaks in cattle was found, especially at the 0.5 cut‐off value (the mean distance to the nearest cattle TB outbreak was 13km for seropositive wild boars). Our results provide a first description of the global seroprevalence and geographic distribution of MTC contact in wild boars in France but they also suggest that the ELISA could be used as a first screening tool to conduct TB surveillance in wild boars at a population level, to be completed, in case of seroposivity, by investigations combining pathology and culture.  L’IREC remercie enfin le projet européen Aphaea (EMIDA ERA‐NET).Peer Reviewe

Epidémiologie de zoonoses du sanglier (Sus scrofa) dans un milieu méditerranéen insulaire, la Corse

This thesis aimed to study the epidemiology of zoonosis in wild boar in Corsica and to provide new elements to analyse and manage the zoonotic risk. The first bibliographical part describes how to analyse a zoonotic risk and which data are needed to estimate it, highlights that wild boar is potentially carrier of numerous pathogens and is a good biological model to survey diseases transmitted to Humans by ingestion or carcass handling, and finally presents the hunting and breeding context in Corsica. The second part presents the active surveillance device built on the whole island to collect epidemiological data, and then the study of three zoonotic pathogens (respectively diseases): Trichinella britovi (trichinellosis), Toxoplasma gondii (toxoplasmosis) and Mycobacterium bovis (bovin tuberculosis). We firstly showed that, although an outbreak of trichinellosis was detected in 2004 in pigs and one fox, the risk is difficult to estimate nowadays due to difficulties in interpreting diagnostic tests in wildlife. However, the risk is still potential and preventive practices need to be maintained (cooking meat, systematic test of commercialised carcasses). Secondly, we show evidence of a strong risk of toxoplasmosis on the whole island, which is stronger in areas with high farm densities. Thirdly, the risk of tuberculosis appears a major one to consider, M. bovis of identical genotypes being found in wild boars, cattle, and pigs of the same areas. Finally, our work leads to suggest a better management of wild and domestic carcasses, and the need of a long-term coordination of the surveillance device built to study zoonosis and detect emerging diseases in Corsica.Cette thèse a pour objectif l'étude épidémiologique de zoonoses chez le sanglier en Corse afin d'éclairer l'analyse et la gestion du risque zoonotique. La première partie décrit la démarche d'analyse du risque et les données nécessaires à son estimation, met en évidence que le sanglier, porteur potentiel de nombreux agents pathogènes, est un modèle biologique intéressant pour le suivi de maladies transmissibles à l'Homme par ingestion ou manipulation de carcasses, et décrit le contexte d'étude, la Corse, notamment sur le plan cynégétique et de l'élevage. La seconde partie présente le dispositif mis en place pour la collecte des données, un réseau d'épidémiosurveillance active à l'échelle de la région insulaire, puis l'étude épidémiologique de trois agents zoonotiques (respectivement maladies) : Trichinella britovi (trichinellose), Toxoplasma gondii (toxoplasmose) et Mycobacterium bovis (tuberculose bovine). A l'issue de nos travaux, le risque de trichinellose, avéré en 2004, demeure difficile à évaluer mais plausible, nécessitant le maintien des consignes de prévention (cuisson de la viande, test des carcasses commercialisées). Le risque de toxoplasmose est fort sur l'ensemble de l'île et davantage encore dans les zones à forte densité d'exploitations agricoles. Le risque de tuberculose apparaît majeur à considérer, le bacille étant présent à la fois chez les sangliers et chez des porcs ou bovins de quatre régions corses. Nos travaux concluent en l'importance d'une meilleure gestion des carcasses et viscères d'animaux sanvages et domestiques, et la nécessité d'une coordination pérenne du dispositif mis en place pour le suivi des zoonoses en Corse

Mycobacterium bovis Infection in Red Foxes in Four Animal Tuberculosis Endemic Areas in France

In France, animal tuberculosis (TB) due to Mycobacterium bovis (M. bovis) affects a multi-host community that include cattle and wildlife species such as wild boars (Sus scrofa), badgers (Meles meles), or wild deer (Cervus elaphus, Capreolus capreolus). The involvement of foxes in the epidemiology of TB is fairly described in countries facing multispecies concerns. After the discovery of grouped cases of TB in foxes in a French TB endemic region, a study was implemented in the core of four TB endemic areas in Dordogne, Charente, Landes (departments of Nouvelle-Aquitaine region), and Côte-d’Or (Burgundy-Franche-Comté region). No infected fox was found in Côte-d’Or (n = 146), where in parallel TB in cattle and other wild species became sparse in the last years. In contrast, in Dordogne, Charente, and Landes, 13 (n = 184), 9 (n = 98) and 7 (n = 140) foxes were found infected by M. bovis, respectively, corresponding to 7.1% (CI95% 3.8–11.8%), 9.2% (4.3–16.7%) and 5.0% (CI95% 2.0–10.0%) prevalence rates, respectively. These infection rates are comparable with those observed in badgers and wild boar in these same three areas (ranging from 9 to 13.2% and 4.3 to 17.9%, respectively), where the number of cattle outbreaks has increased in the last 10-15 years. In each area, the genotypes of foxes’ M. bovis isolates were the same as those in local cattle and other wildlife species. None of the infected foxes presented TB-like gross lesions. M. bovis was found in the mesenteric lymph nodes of 28 foxes (68%). For the 12 foxes where retropharyngeal and respiratory lymph nodes were analyzed separately, M. bovis was present in the respiratory lymph nodes of eight individuals. With regard to excretion, appropriate samples were available for 12 infected foxes from Dordogne. M. bovis DNA was detected in the feces of five of these animals, four of which were infected in the mesenteric lymph nodes. Combined with the knowledge on the biology and ecology of foxes, the results of this study suggest that in areas where infection in cattle is still active in France, foxes might play a role of spillover host in the epidemiology of M. bovis

Exposure of wild boar to Mycobacterium tuberculosis complex in France since 2000 Is consistent with the distribution of bovine tuberculosis outbreaks in cattle

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.The Eurasian wild boar (Sus scrofa) is increasingly considered as a relevant actor in the epidemiology of animal tuberculosis (TB). Therefore, monitoring TB in wild boar becomes a key tool for establishing comprehensive control schemes for this disease. To estimate the exposure of free living wild boar to Mycobacterium tuberculosis complex (MTC) in France, a bovine-purified protein derivative based ELISA was used to test 2,080 archived serum samples of hunter-harvested animals in 58 French “départements”. Two cut-off values were used for diagnostic interpretation: 0.2, recommended by the manufacturer (specificity: 96.43%; sensitivity: 72.6%), and 0.5 (specificity: 100%; sensitivity: 64%). During the same period, at the 0.2 cut-off, global true seroprevalence was 5.9% (IC95%: 4.3%-7.7%) and 76% of the sampled “départements” had seropositive wild boar, including seven cattle TB-free “départements. At the 0.5 cut-off, global true seroprevalence was 2.2% (IC95%: 1.5-3.2) and positive wild boar belonged to 21% of the “départements”. All but one of these positive “départements” had reported at least one cattle TB outbreak since 2000. A good consistence between seropositive wild boar and TB outbreaks in cattle was found, especially at the 0.5 cut-off value (the mean distance to the nearest cattle TB outbreak was 13km and 27km for seropositive and seronegative wild boar, respectively; P<0.05). The use of an ELISA to detect MTC antibodies in wild boar has permitted the description of the geographic distribution of MTC contact in wild boar in France. Our results suggest that the ELISA could be used as a first screening tool to conduct TB surveillance in wild boar at a population level. High-risk wild boar populations (e.g. overabundant) could be tested and if identified positive by ELISA they should be surveyed in detail by combining pathology and culture.This study was funded by our own institutional resources (Anses).Peer reviewe