François Casabianca

Bovine Tuberculosis in Livestock and Wild Boar on the Mediterranean Island, Corsica

The zoonotic agent of bovine tuberculosis (bTB), Mycobacterium bovis, can be transmitted between domestic and wild animals, threatening wildlife populations and control programs for bTB in cattle. In Corsica, a French Mediterranean island where domestic and wild species have close interactions, bTB cases have been reported in cattle, pigs, and wild boar. Moreover, genotypes of M. bovis found in wild and domestic animals from the same area were identical. These data strongly suggest that wild and domestic animals are associated in an epidemiologic bTB-transmission cycle. More investigations are needed, not only to understand the role played by each species in order to implement appropriate control measures, but also to assess the risk of transmission to humans.

Assessment of Domestic Pigs, Wild Boars and Feral Hybrid Pigs as Reservoirs of Hepatitis E Virus in Corsica, France

In Corsica, extensive pig breeding systems allow frequent interactions between wild boars and domestic pigs, which are suspected to act as reservoirs of several zoonotic diseases including hepatitis E virus (HEV). In this context, 370 sera and 166 liver samples were collected from phenotypically characterized as pure or hybrid wild boars, between 2009 and 2012. In addition, serum and liver from 208 domestic pigs belonging to 30 farms were collected at the abattoir during the end of 2013. Anti-HEV antibodies were detected in 26% (21%–31.6%) of the pure wild boar, 43.5% (31%–56.7%) of hybrid wild boar and 88% (82.6%–91.9%) of the domestic pig sera. In addition, HEV RNA was detected in five wild boars, three hybrid wild boars and two domestic pig livers tested. Our findings provide evidence that both domestic pig and wild boar (pure and hybrid) act as reservoirs of HEV in Corsica, representing an important zoonotic risk for Corsican hunters and farmers but also for the large population of consumers of raw pig liver specialties produced in Corsica. In addition, hybrid wild boars seem to play an important ecological role in the dissemination of HEV between domestic pig and wild boar populations, unnoticed to date, that deserves further investigation.

Genetic Structure of Human A/H1N1 and A/H3N2 Influenza Virus on Corsica Island: Phylogenetic Analysis and Vaccine Strain Match, 2006–2010

Background The aim of this study was to analyse the genetic patterns of Hemagglutinin (HA) genes of influenza A strains circulating on Corsica Island during the 2006–2009 epidemic seasons and the 2009–2010 pandemic season. Methods Nasopharyngeal samples from 371 patients with influenza-like illness (ILI) were collected by General Practitioners (GPs) of the Sentinelles Network through a randomised selection routine. Results Phylogenetic analysis of HA revealed that A/H3N2 strains circulating on Corsica were closely related to the WHO recommended vaccine strains in each analyzed season (2006–2007 to 2008–2009). Seasonal Corsican influenza A/H1N1 isolated during the 2007–2008 season had drifted towards the A/Brisbane/59/2007 lineage, the A/H1N1 vaccine strain for the 2008–2009 season. The A/H1N1 2009 (A/H1N1pdm) strains isolated on Corsica Island were characterized by the S220T mutation specific to clade 7 isolates. It should be noted that Corsican isolates formed a separate sub-clade of clade 7 as a consequence of the presence of the fixed substitution D222E. The percentages of the perfect match vaccine efficacy, estimated by using the p epitope model, against influenza viruses circulating on Corsica Island varied substantially across the four seasons analyzed, and tend to be highest for A/H1N1 compared with A/H3N2 vaccines, suggesting that cross-immunity seems to be stronger for the H1 HA gene. Conclusion The molecular analysis of the HA gene of influenza viruses that circulated on Corsica Island between 2006–2010 showed for each season the presence of a dominant lineage characterized by at least one fixed mutation. The A/H3N2 and A/H1N1pdm isolates were characterized by multiples fixation at antigenic sites. The fixation of specific mutations at each outbreak could be explained by the combination of a neutral phenomenon and a founder effect, favoring the presence of a dominant lineage in a closed environment such as Corsica Island.

Possible Foodborne Transmission of Hepatitis E Virus from Domestic Pigs and Wild Boars from Corsica.

Author affiliations: ANSES (French Agency for Food, Environmental and Occupational Health and Safety), Maisons-Alfort, France (N. Pavio); INRA (National Institute for Agricultural Research), Maisons-Alfort (N. Pavio); University Paris 12, National Veterinary School, Maisons-Alfort (N. Pavio); INRA, Corte, France (M. Laval, O. Maestrini, F. Casabianca, F. Charrier); CIRAD (Agricultural Research for Development), Montpellier, France (F. Jori); Botswana University of Agriculture and Natural Resources, Gaborone, Botswana (F. Jori)

A dig into the past mitochondrial diversity of Corsican goats reveals the influence of secular herding practices

The goat (Capra hircus) is one of the earliest domesticated species ca. 10,500 years ago in the Middle-East where its wild ancestor, the bezoar (Capra aegagrus), still occurs. During the Neolithic dispersal, the domestic goat was then introduced in Europe, including the main Mediterranean islands. Islands are interesting models as they maintain traces of ancient colonization, historical exchanges or of peculiar systems of husbandry. Here, we compare the mitochondrial genetic diversity of both medieval and extant goats in the Island of Corsica that presents an original and ancient model of breeding with free-ranging animals. We amplified a fragment of the Control Region for 21 medieval and 28 current goats. Most of them belonged to the A haplogroup, the most worldwide spread and frequent today, but the C haplogroup is also detected at low frequency in the current population. Present Corsican goats appeared more similar to medieval goats than to other European goat populations. Moreover, 16 out of the 26 haplotypes observed were endemic to Corsica and the inferred demographic history suggests that the population has remained constant since the Middle Ages. Implications of these results on management and conservation of endangered Corsican goats currently decimated by a disease are addressed.

Questionnaire-Based Assessment of Wild Boar/Domestic Pig Interactions and Implications for Disease Risk Management in Corsica

Wild boars and domestic pigs belong to the same species (Sus scrofa). When sympatric populations of wild boars, feral pigs, and domestic pigs share the same environment, interactions between domestic and wild suids (IDWS) are suspected to facilitate the spread and maintenance of several pig pathogens which can impact on public health and pig production. However, information on the nature and factors facilitating those IDWS are rarely described in the literature. In order to understand the occurrence, nature, and the factors facilitating IDWS, a total of 85 semi-structured interviews were implemented face to face among 25 strict farmers, 20 strict hunters, and 40 hunting farmers in the main traditional pig-farming regions of Corsica, where IDWS are suspected to be common and widespread. Different forms of IDWS were described: those linked with sexual attraction of wild boars by domestic sows (including sexual interactions and fights between wild and domestic boars) were most frequently reported (by 61 and 44% of the respondents, respectively) in the autumn months and early winter. Foraging around common food or water was equally frequent (reported by 60% of the respondents) but spread all along the year except in winter. Spatially, IDWS were more frequent in higher altitude pastures were pig herds remain unattended during summer and autumn months with limited human presence. Abandonment of carcasses and carcass offal in the forest were equally frequent and efficient form of IDWS reported by 70% of the respondents. Certain traditional practices already implemented by hunters and farmers had the potential to mitigate IDWS in the local context. This study provided quantitative evidence of the nature of different IDWS in the context of extensive commercial outdoor pig farming in Corsica and identified their spatial and temporal trends. The identification of those trends is useful to target suitable times and locations to develop further ecological investigations of IDWS at a finer scale in order to better understand diseases transmission patterns between populations and promote adapted management strategies.

Adding value to local breeds: challenges, strategies and key factors

This paper analyzes the articles published in this special issue and also some material presented at the Session “Strategies to add value to local breeds” of the 61st Annual Meeting of the European Federation of Animal Science (EAAP) (August, 2010, Crete, Greece) 1 or at other workshops dealing with the issue of adding value to local breeds. The analysis refers to the challenges facing local breeds and the different strategies that can be used to increase their value and thereby enhance their sustainability. These strategies can be categorized, inter alia , according to the species, the specific characteristics of the targeted breeds or production systems, the existence or absence of markets and the characteristics and dynamics of the breeders and other stakeholders. The paper is structured as follows: presentation of an overview of the challenges involved; this is followed by a discussion of strategies for adding value to breeds, which is illustrated with examples; an analysis of the key factors affecting such strategies and ends with some conclusions. Questions remain regarding the societys responsibility for providing support to farmers that keep local breeds that are at risk of extinction and regarding what actions are appropriate when such a breed that was once at risk becomes self-sustainable or, in contrast, when a breed ceases to be self-sustained.

Aujeszky's disease and hepatitis E viruses transmission between domestic pigs and wild boars in Corsica: Evaluating the importance of wild/domestic interactions and the efficacy of management measures

Wildlife species as reservoirs of infectious pathogens represent a serious constraint in the implementation of disease management strategies. In the Mediterranean island of Corsica, the dynamics of hepatitis E virus (HEV) and Aujeszky’s disease virus (ADV) are suspected to be influenced by interactions between wild and domestic pigs. To improve our understanding of these influences, we first compared the seroprevalences of both viruses in domestic pig populations from different locations with contrasted levels of wild–domestic interactions, ADV vaccination, biosafety, and farm husbandry. Second, we performed an analysis at a more restricted geographical scale, to assess the matching of ADV or HEV prevalence between sympatric wild boar and outdoor pig farms most exposed to interactions with wildlife. Logistic models were adjusted to the observed data. A high seroprevalence of HEV (>80%) and ADV (40%) in pigs, with no significant difference according to the region, confirms that both pathogens are enzootic in Corsica. Vaccination against ADV had a strong protective effect, even when performed voluntarily by farmers. Farm biosafety had an additional effect on pigs’ exposure, suggesting that contact between wild boars and pigs were involved in disease transmission. A strong correlation in HEV seroprevalence was observed between pigs and wild boars that were in close contact, and significantly lower seroprevalence was observed in pigs when they had little contact with wild boars due to spatial segregation. These results suggest a regular HEV circulation between sympatric wild boar and domestic pigs. The high HEV seroprevalence observed in domestic pigs (>80%) suggests a spillover of the virus from domestic to wild populations through environmental contamination, but this hypothesis has to be confirmed. Conversely, even though avoiding sows’ release on pasture during estrus showed some protecting effect in the free ranging pig farms regarding ADV, ADV seroprevalence was not dependent on the swine populations (wild or domestic) or on the wild–domestic spatial overlap, suggesting two quasi-separate enzootic cycles. This information will prove useful for designing more efficient disease management strategies in Corsica and similar contexts.

Serological survey of influenza A viruses in domestic and wild Suidae in Corsica (France), a Mediterranean island environment

Corsica is a mountainous French island in the north-western Mediterranean Sea. It is a rural area, where pig farming is a major economic activity. Although no acute respiratory outbreaks due to swine influenza A viruses (swIAVs) have ever been reported in this free-ranging pig breeding system, influenza A viruses (IAVs) could be circulating within this pig population. A serological study was conducted as a first approach to domestic pigs and wild boars. Serum samples from 543 pigs raised on 91 different farms were collected during the 2013-2014 slaughtering season, and 279 sera from wild boars were obtained over four hunting seasons (between 2009 and 2014). They were first analysed by ELISA and then IAV positive and doubtful sera were subjected to haemagglutination inhibition tests using antigens representative of the four major enzootic swIAV lineages in Europe, i.e. avian-like swine H1N1 (H1avN1), pandemic-like swine H1N1 (H1N1pdm), H1N2 and H3N2. According to the ELISA results, 26.4% (CI95%: 17.7-36.7%) of herds had at least one positive animal (positive or doubtful by ELISA) and 12.4% (CI95%: 7.8-19.8%) of the pigs tested positive. Using the test characteristics (sensitivity and specificity), the true seroprevalence among Corsican pigs was estimated to be 16.4% (95% CI: 9.9-26.3). Antibodies directed against two different viral lineages were identified: H1N1pdm (in 66.2% and 45.8% of the IAV positive pigs and farms respectively) and H1avN1 (15.0% and 20.8% respectively). Evidence of exposure to viruses from two distinct lineages were detected on a single farm but in two different animals. Among the wild boars, 1.4% (CI95%: 0.4-3.6%) tested positive by ELISA and antibodies against the same two viruses were detected. Altogether, these results suggest that swIAVs from at least two different lineages are circulating among Corsican pigs, i.e. the H1N1pdm virus, probably introduced during the 2009 pandemic, and the H1avN1 virus, which is the most frequent swIAV in Europe. The low frequency of positive results observed in the Corsican wild boars hunted suggests that they would not play a major role in IAV dispersion dynamics on the island.

Multilocus genotype analysis outlines distinct histories for Trichinella britovi in the neighboring Mediterranean islands of Corsica and Sardinia

BackgroundThe zoonotic nematode Trichinella britovi was discovered in two neighboring Mediterranean islands of Corsica and Sardinia, almost simultaneously at the beginning of the 21st century. An epidemiological link between the two parasite populations was generally assumed. In 2015, an outbreak of trichinellosis in Nice, the South of France, was reportedly caused by the consumption of raw pork delicatessen imported from Corsica. The aims of the present study were to investigate, by multilocus genotype (MLG) analyses, the hypothesis of the common origin of the Corsican and Sardinian T. britovi foci and to trace “from fork to farm” the origin of the pork product, which caused a trichinellosis outbreak in mainland France in 2015.MethodsSixty-three T. britovi isolates were collected from animals and pork products of Sardinia and Corsica islands and from mainland of Italy, France and Spain. We analyzed genetic variability at four polymorphic microsatellite loci by two independent algorithms, the Bayesian and multivariate analyses, to evaluate the genetic relationships of 1367 single larvae.ResultsTrichinella britovi isolates of the two islands showed different genetic structures and the Bayesian analysis revealed a different membership of the two insular populations. Furthermore, two geographically separate genetic groups were identified among Corsican isolates. Lastly, the origin of the pork delicatessen marketed in Nice was linked to a breeder-butcher in Corsica.ConclusionsThe low level of genetic admixture of the insular T. britovi isolates suggests that this pathogen colonized the two islands by separate events. On the other hand in Corsica, although the isolates share the same genetic structure, geographically separate isolates showed different membership. We suggest the MLG analysis as a suitable method in supporting epidemiological investigations to trace “from fork to farm” insular populations of T. britovi.