Results of the surveillance of regulated contagious diseases in the french wildlife

The FrenchMinistry of Agriculture, the National Hunting andWildlife Agency (ONCFS) and the hunters’ associations are increasingly concerned with the impact of wildlife diseases on livestock and human health. The demographic growth of some wild species is further increasing this risk. In France, wildlife diseases aremonitored passively through the SAGIR network, whose objective is to diagnose the causes of wildlife mortality, and actively by targeting certain species and diseases with a major economic or public health impact. This surveillance programhas shown for instance that wild boars act as a reservoir for Brucella suis biovar 2 and the Aujeszky’s disease virus, and that they are responsible for the contamination of open-air pig farms, as well as for the persistence for over fifteen years of the virus of classical swine fever in the North-East of France and in other parts of Europe. Oral vaccination of wild boars had been thus implemented since 2004 in order to control the enzooty. Since 2001, cases of bovine tuberculosis due to Mycobacterium bovis have been identified in red deer and wild boar in several areas of France, which threaten disease-free livestock. Likewise, the question of a possible role of wild ruminants in the epidemiology of Bluetongue disease is being raised. Finally, wild birds constitute uncontrollable reservoirs for influenza andWest Nile viruses, among others, and may threaten domestic poultry, humans or horses. The sanitary status of wild species is thus increasingly taken into account in the management and control of livestock diseases.Les ministères chargés de l'Agriculture et le monde cynégétique sont de plus en plus préoccupés par le risque sanitaire que peut représenter la faune sauvage pour les animaux d'élevage et l'homme. Ce risque est aggravé par la croissance démographique de certaines espèces sauvages. En France, l'épidémiosurveillance des maladies de la faune sauvage est assurée par le réseau SAGIR dont l'objectif est de diagnostiquer les causes de mortalité des animaux sauvages (surveillance passive), ainsi que par la mise en oeuvre de plans de surveillance ciblés sur certaines espèces et sur des maladies à impact économique ou zoonotique majeur (surveillance active). Les résultats de cette surveillance montrent, par exemple, que le sanglier est un réservoir de Brucella suis biovar 2 et du virus de la maladie d'Aujeszky, responsable de la contamination d'élevages de porcs en plein air, et qu'il entretient depuis plus de quinze ans le virus de la peste porcine classique dans le nord-est de la France, comme dans d'autres régions d'Europe. Depuis 2001, des cas de tuberculose bovine à Mycobacterium bovis ont été découverts chez les cerfs et les sangliers dans plusieurs départements, laissant peser un risque de recontamination de cheptels bovins indemnes. De même, la question du rôle joué par les ruminants sauvages dans l'épidémiologie de la fièvre catarrhale ovine est posée. Enfin, les oiseaux sauvages, réservoirs incontrôlables des virus influenza et du virus West Nile pour ne citer qu'eux, peuvent représenter un risque pour les volailles, l'homme ou le cheval. De ce fait, la faune sauvage est maintenant prise en compte dans les mesures de gestion sanitaire des maladies animales

Lesional aspects of Brucella melitensis in Capra ibex

Suite à la découverte d’une forte séroprévalence de brucellose dans les populations de bouquetins du massif du Bargy, il est apparu indispensable d’étudier la pathogénie de la maladie afin de mieux comprendre cette relation hôte-pathogène. Des autopsies ont été réalisées entre 2012 et 2014 sur 64 bouquetins atteints, complétées par des analyses bactériologiques. Près d’un bouquetin sur trois était porteur d’au moins une lésion évoquant la brucellose et l’infection pouvait avoir plusieurs localisations chez un même animal. Les arthrites et les orchites étaient les lésions les plus fréquemment observées. La période de capture et le sexe des individus ont été identifiés comme facteurs de risque faisant varier l’atteinte lésionnelle parmi la population. La nature des lésions observées et l’isolement de la bactérie prouvent l’existence d’animaux excréteurs sans aucun signe clinique et laissent entrevoir plusieurs voies d’excrétion. Le bouquetin des Alpes semble donc, d’après la pathogénie de la brucellose, pouvoir constituer un réservoir pour B. melitensis.After the evidence of a high seroprevalence of brucellosis in Alpine ibex populations in the French Alps (Bargy massif), it became essential to study the pathogeny of the disease in this wild ungulate. Necropsies were achieved between 2012 and 2014 on 64 affected ibex, supplemented by bacteriologic analysis. About one ibex out of three showed at least one typical lesion of brucellosis and infection could have several locations on the same animal. Arthritis and orchitis were lesions the most frequently observed. Year of capture and sex of animals were identified as risk factors for ibex to develop clinical signs of the disease. These types of lesions and isolation of the bacteria demonstrate the possibility for individuals to excrete B. melitensis without clinical signs and suggest various excretion routes. According to the brucellosis pathogeny, the Alpine ibex seems to be able to constitute a wildflife reservoir for B. melitensis

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

Emerging diseases of wildlife in Europe : Lessons to draw to prevent a resurgence of avian influenza

The incursion of Highly Pathogenic Avian Influenza among wildfowl in Europe in 2006 was a new illustration of the health risk presented by wildlife to humans and domestic animals. To help anticipate similar incursions and avoid the pitfalls of poor communication, this paper describes how this risk was analysed and managed in the past for other wildlife diseases in Europe. The author also proposes a general methodology to anticipate such events.La contamination de l'avifaune sauvage en Europe, en 2006, par des foyers d'Influenza Aviaire Hautement Pathogène (IAHP) a été une nouvelle illustration du risque sanitaire que représente la faune sauvage pour l'homme ou les animaux domestiques. Afin de mieux anticiper des incursions similaires et éviter les dérives liées à une communication mal conduite, cet article décrit la façon dont le risque a été étudié et géré dans le passé pour d'autres maladies de la faune sauvage en Europe. L'auteur propose aussi une méthodologie générale pour anticiper de tels événements

Sociospatial structure explains marked variation in brucellosis seroprevalence in an Alpine ibex population

International audienceIn a context of (re)emerging infectious diseases with wildlife reservoirs, understanding how animal ecology shapes epidemiology is a key issue, particularly in wild ungulates that share pathogens with domestic herbivores and have similar food requirements. For the first time in Europe, brucellosis (Brucella melitensis), a virulent zoonosis, persisted in an Alpine ibex (Capra ibex) population and was transmitted to cattle and humans. To better understand disease dynamics, we investigated the relationships between the spatial ecology of ibex and the epidemiology of brucellosis. Combining home range overlap between 37 GPS-collared individuals and visual observations of 148 visuallymarked individuals monitored during the 2013-2016 period, we showed that females were spatially segregated in at least 4 units all year round, whereas males were more prone to move between female units, in particular during the rutting period. In addition to ibex age, the spatial structure in females largely contributed to variation in seroprevalence in the whole population. These results suggest that non-sexual routes are the most likely pathways of intraspecific transmission, crucial information for management. Accounting for wildlife spatial ecology was hence decisive in improving our ability to better understand this health challenge involving a wildlife reservoir

Management of a wild reservoir : Swine fever in European wild boars (sus scrofa)

Classical swine fever (CSF) is a disease affecting wild and domestic Suidae. Wild boars (Sus scrofa) are considered as a reservoir for the disease, as CSF may persist for years in certain wild populations. The presence of this infection is a threat for the pig industry in the European Union where most of the member States are free of CSF.We describe the possible outcomes of an outbreak of CSF in wild animals, as well as the factors likely to influence the virus transmission and persistence. We also detail the management measures that were tested to date to prevent geographical spreading from the infected zones, and to eradicate CSF within the infected areas. The complexity of health measures dealing with an outbreak within natural populations is explained, with further details on the vaccination approach implemented in France since 2004.La peste porcine classique (PPC) est une maladie virale des Suidés domestiques et sauvages. Le sanglier (Sus scrofa) est considéré comme un réservoir de PPC car la maladie peut persister plusieurs années dans certaines populations sauvages. Or la présence de cette infection représente une menace pour la filière porcine de l'union européenne dont la plupart des États membres sont indemnes. Nous présentons ici les évolutions possibles d'un foyer sauvage de PPC en déclinant les facteurs probables de la transmission et de la persistance du virus. Nous abordons ensuite les différents moyens de gestion qui ont été mis en place jusqu'à aujourd'hui pour empêcher l'extension des zones infectées, et permettre l'éradication des foyers au sein des zones infectées. L'accent est mis sur la complexité de la gestion sanitaire d'un foyer en population naturelle. Un développement plus particulier est consacré à la gestion vaccinale qui est mise en oeuvre en France depuis 2004

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

New Insights on the Management of Wildlife Diseases Using Multi-State Recapture Models: The Case of Classical Swine Fever in Wild Boar

The understanding of host-parasite systems in wildlife is of increasing interest in relation to the risk of emerging diseases in livestock and humans. In this respect, many efforts have been dedicated to controlling classical swine fever (CSF) in the European Wild Boar. But CSF eradication has not always been achieved even though vaccination has been implemented at a large-scale. Piglets have been assumed to be the main cause of CSF persistence in the wild since they appeared to be more often infected and less often immune than older animals. However, this assumption emerged from laboratory trials or cross-sectional surveys based on the hunting bags.In the present paper we conducted a capture-mark-recapture study in free-ranging wild boar piglets that experienced both CSF infection and vaccination under natural conditions. We used multi-state capture recapture models to estimate the immunization and infection rates, and their variations according to the periods with or without vaccination. According to the model prediction, 80% of the infected piglets did not survive more than two weeks, while the other 20% quickly recovered. The probability of becoming immune did not increase significantly during the summer vaccination sessions, and the proportion of immune piglets was not higher after the autumn vaccination.Given the high lethality of CSF in piglets highlighted in our study, we consider unlikely that piglets could maintain the chain of CSF virus transmission. Our study also revealed the low efficacy of vaccination in piglets in summer and autumn, possibly due to the low palatability of baits to that age class, but also to the competition between baits and alternative food sources. Based on this new information, we discuss the prospects for the improvement of CSF control and the interest of the capture-recapture approach for improving the understanding of wildlife diseases