Jean-Jacques Bénet

Determination of decisional cut-off values for the optimal diagnosis of bovine tuberculosis with a modified IFNγ assay (Bovigam®) in a low prevalence area in France

The Bovigam(®) gamma interferon (IFNγ) assay was used to complement official skin-test screening in a low bovine tuberculosis (bTB) prevalence region in France. The aim of our work was to determine decisional cut-off values for protein purified derivatives (PPD) and ESAT6-CFP10 antigens (R) in order to optimize the efficacy of the modified Bovigam(®) test, in this low-prevalence area, for optimal classification of infected or non-infected herds following positive skin tests. The sensitivity of the IFNγ assay relative to post-mortem bTB-positive animals (Se(r)) was studied in 60 cattle from 20 bTB-infected herds. Its absolute specificity (Sp) was studied in 492 cattle from 25 bTB-free herds from a bTB-free zone. Its operational specificity (relative to the positive skin test) (Sp(r)) was also studied in 547 skin-test positive cattle from 172 bTB-free herds from an infected zone. Using normalized interpretations for individual (PPD or R) results, the cut-off values at 0.02 for PPD and 0.01 for R were obtained with a view to employ them in low prevalence areas with no previously observed non-specific reactions to SITT. Concerning its use after positive skin tests, cut-off values were set at 0.05 for PPD and at 0.03 for R. The choice of an interpretation method considering positive results with PPD and/or R (PPDUR), justified in a high risk context, provided a test Se(r) of 93% [84-98] and Sp(r) of 71.8% [67.9-75.6]. Analysis of positive results with PPD and R (PPDUR), ideal for low-risk contexts, provided a test Sp(r) of 94.3% [92.0-96.1] and Se(r) of 77% [64-87]. Thus, adapting the criteria to the regions infection status and to the conditions for its application is essential for the appropriate use of the IFNγ assay.

L’infection à Mycobacterium bovis en France en 2014 : recrudescence et inquiétudes

Resume Pratiquement quarante ans apres le lancement a l’echelle nationale (1963) du plan d’eradication de la tuberculose bovine (infection a Mycobacterium bovis) dans les elevages, la France a obtenu (decembre 2000) le statut europeen de pays « officiellement indemne de tuberculose bovine ». L’infection n’a toutefois pas totalement disparu des elevages francais et une certaine tendance a la recrudescence de l’infection dans les elevages inquiete les autorites sanitaires. Parallelement, l’infection a ete identifiee dans la faune sauvage en 2001 en Normandie sur des cervides, puis dans d’autres regions sur des sangliers et des blaireaux. Les causes possibles d’une telle recrudescence sont analysees dans cet article. En supplement des facteurs de risque traditionnels (resurgence de l’infection dans des foyers, introduction d’animaux infectes et risques lies au voisinage avec des exploitations infectees), de nouveaux facteurs de risque sont apparus ; ils sont lies : – a la limite des outils de depistage qui en situation de tres faible prevalence presentent des valeurs predictives positives tres basses ; – a la taille des troupeaux et aux modalites d’elevage augmentant les risques d’infection notamment des elevages producteurs de viande ; – a l’infection dans la faune sauvage qui au depart est une consequence de l’infection bovine mais qui peut egalement, par des contacts indirects (frequentation des memes points ou de pâturages communs), contaminer des elevages sains. Malgre cette recrudescence, les risques de transmission a l’homme de cette infection zoonotique demeurent en France en 2015 tres faibles.

Characterisation of the French ferret population, husbandry, reported medical care and feeding habits

Ferrets have become a common companion animal. But no data are available on the French population of ferrets. The goal of the survey was to characterise this population, including demographic characteristics, husbandry, reported medical care and feeding habits. Complete data were available for 1205 pet ferrets in 709 households. Most ferrets (86·1 %) lived indoors, 1 % received only artificial lighting, and 47 % chewed their cage. For 60 % of the ferrets, body weight was higher in winter and lower in summer. Neutered ferrets (58·5 % of males and 62·9 % of females) appeared lighter than intact ferrets of comparable age. A majority (52·4 %) of ferrets received a mix of commercial foods and fresh foods, but 28·6 % were offered no commercial foods. Data were analysed using several multivariable logistic regression models including age, sex, castration, food type and artificial lighting developed for four clinical outcome (lethargy and/or insulinoma, dental problems, diarrhoea and/or bird-seed stools and alopecia). Predictors of four clinical outcomes (lethargy, dental disease, diarrhoea and alopecia) were examined using multivariable logistic regression, with age, sex, neuter status, food type and artificial lighting as the exposure variables. Aged ferrets were more likely to have lethargy, insulinoma, dental problems and alopecia. Ferrets with artificial lighting were more likely to show alopecia. Additionally, ferrets fed commercial food only or a mixed diet (both commercial food and fresh food) were more likely to have lethargy, insulinoma, dental problems, diarrhoea and/or bird-seed stools compared with ferrets fed fresh food only. We also found a significant association between neutering and alopecia. It is to our knowledge the first description of the French population of the ferret as a companion animal.