Observation of a maternal transmission of scrapie in sheep

A pregnant ewe with suspected scrapie was referred to the Regional Veterinary Laboratory in Limoges on 11 January 2002, in compliance with the French scrapie eradication program. Western Blot confirmed the diagnosis of scrapie. Ten days later, the ewe gave birth. As we had to help the ewe, we were able to isolate the ewe lamb before she had any contact with her mother, and especially no colostrum. The ewe lamb was fed with milk replacers and isolated to prevent all possibility of horizontal transmission of scrapie. In August 2002, the first symptoms of scrapie appeared in the ewe lamb. Euthanasia was decided on 18 December 2002, as the animal was no longer able to stand. Western Blot and immunohistochemistry tests confirmed natural scrapie in the ewe lamb. PrP genotyping of this lamb was ARQ/VRQ. This first confirmed case of maternal transmission of scrapie in sheep is associated with a particularly short incubation time (6 months) in natural conditions.Dans le cadre du programme d'éradication de la tremblante en France, nous avons reçu une brebis gestante suspecte de tremblante le 11 janvier 2002, au laboratoire vétérinaire départemental de Limoges (confirmée ultérieurement par un Western Blot). Dix jours plus tard, la brebis agnela avec difficulté et nous avons dû intervenir pour l'aider. Cette assistance à l'agnelage nous permit d'isoler immédiatement le nouveau-né, en évitant tout contact ultérieur avec sa mère, en particulier sans la possibilité d'absorber le colostrum. L'agnelle fut placée dans un endroit isolé sans qu'il n'y ait de possibilité de transmission horizontale de la tremblante et fut nourrie avec des lactoremplaceurs. En août 2002, les premiers symptômes de la tremblante sont apparus chez l'agnelle née de cette brebis. Du fait d'une évolution vers le décubitus, l'euthanasie de l'agnelle fut décidée le 18 décembre 2002. La confirmation d'une tremblante naturelle chez l'agnelle a été obtenue par le Western-Blot et les examens immunohistochimiques. Le génotype de l'agnelle était ARQ/VRQ. Cette première confirmation d'une transmission maternelle de la tremblante chez le mouton s'accompagne aussi d'un temps d'incubation particulièrement court (6 mois) dans les conditions naturelles

Chlamydiosis of ruminants: experimental studies. III Pathogenic and antigenic power of Chlamydia psittaci (var. ovis) through aerial way in the mice

L'inoculation par voie respiratoire (nébulisation) d'une suspension virulente de Chlamydia psittaci, variété ovis, d'isolement récent (quatrième passage en ovoculture) provoque, chez 100 p. 100 des souris S.P.F. utilisées, l'évolution d'une pneumonie spécifique mortelle. Cette inoculation d'épreuve est, par contre, sans effet chez 90 p. 100 des souris soumises, trois fois au cours des 5 semaines qui la précèdent, à une nébulisation du même antigène, purifié, inactivé par le fréon et adsorbé sur phosphate acide de calcium. La part qui revient, dans cette protection, au phosphate de calcium, est discutée.Inoculation by respiratory route ( nébulisation ) of a virulent, recently isolated, strain of Chlamydia psittaci (vor. ovis) results, in 100 p. 100 of mice S.P.F., in death by specific pneumonia. Differently the same inoculation results in only 10 p. 100 of death of mice if subjected, three times during the five previous weeks, to nébulisation with the same antigen, purified, inactivated by freon and adsorbed on calcium acid phosphate. The part of calcium acid phosphate, in this protection, is discussed

Retrospective Analysis of a Listeria monocytogenes Contamination Episode in Raw Milk Goat Cheese Using Quantitative Microbial Risk Assessment tools

In 2005, the Belgian authorities reported a Listeria monocytogenes contamination episode in cheese made from raw goat's milk. The presence of an asymptomatic shedder goat in the herd caused this contamination. On the basis of data collected at the time of the episode, a retrospective study was performed using an exposure assessment model covering the production chain from the milking of goats up to delivery of cheese to the market. Predictive microbiology models were used to simulate the growth of L. monocytogenes during the cheese process in relation with temperature, pH, and water activity. The model showed significant growth of L. monocytogenes during chilling and storage of the milk collected the day before the cheese production (median increase of 2.2 log CFU/ml) and during the addition of starter and rennet to milk (median increase of 1.2 log CFU/ml). The L. monocytogenes concentration in the fresh unripened cheese was estimated to be 3.8 log CFU/g (median). This result is consistent with the number of L. monocytogenes in the fresh cheese (3.6 log CFU/g) reported during the cheese contamination episode. A variance-based method sensitivity analysis identified the most important factors impacting the cheese contamination, and a scenario analysis then evaluated several options for risk mitigation. Thus, by using quantitative microbial risk assessment tools, this study provides reliable information to identify and control critical steps in a local production chain of cheese made from raw goat's milk