Bayesian estimation of flock-level sensitivity of detection of Salmonella spp., Enteritidis and Typhimurium according to the sampling procedure in French laying-hen houses.

A study was carried out to estimate the prevalence of flocks infected by Salmonella spp., S. Enteritidis and S. Typhimurium in 521 French laying-hen farms from October 1st 2004 to September 30th 2005 as part of a European Union-wide baseline study to define targets for Salmonella reduction in member states. The sampling scheme prescribed and financed by the European Commission to detect Salmonella in laying-hen flocks was based on 2 dust-samples and 5 faeces-samples per farm. A latent-class Bayesian approach for correlated tests was used to estimate the sensitivity of detection of reduced sampling schemes corresponding to the 16 combinations of 2 dust- and 5 faeces-samples. For each model the full sampling scheme (7 samples) and the reduced protocol were considered as two correlated tests, the biological principle being identical and the reduced protocol being a subset of the full sampling scheme. As the observed apparent prevalence in cage flocks was higher than in other systems (barns, outdoor, or organic) these two sub-populations were considered separately. Bayesian estimation of posterior medians with 95% probability intervals for true prevalence in cage flocks were 0.34 (0.29; 0.39) and 0.13 (0.10; 0.18) for Salmonella spp. and Salmonella Enteritidis+Typhimurium respectively. In alternative flocks posterior medians with 95% probability intervals for true prevalence were 0.09 (0.06; 0.13) and 0.05 (0.03; 0.08) for Salmonella spp. and Salmonella Enteritidis+Typhimurium, respectively. In cage flocks Bayesian estimation of posterior distributions for sensitivity indicated that at least 5 samples, including 2 dust samples were necessary to attain comparable sensitivity levels to the full sampling scheme. In alternative flocks and for Salmonella spp. 6 samples were required to ensure a comparable sensitivity level to the full sampling scheme. Detection sensitivity was improved by increasing the number of dust samples in cage farms and by increasing the total number of samples whatever their type in alternative farms.

Evaluation of a French ELISA for the detection of Salmonella Enteritidis and Salmonella Typhimurium in flocks of laying and breeding hens.

In France, the regular and compulsory detection of Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) in flocks of breeding and laying hens is based on bacteriological examination of environmental swabs and faeces samples. The aim of this study was to compare this bacteriological examination with a serological method (ELISA) developed in our laboratory. This ELISA was first evaluated by use of artificially infected hens. During these experimental infection studies, several groups of hens were inoculated with SE, ST, different vaccines and different Salmonella serovars to calculate the experimental parameters of our ELISA. Then, in a field study, 43 flocks were followed monthly using two bacteriological samples (environmental swab and pool of faeces) and 20 serological samples (sera or yolks). Twenty-seven flocks without SE or ST gave a negative serological response throughout their surveillance. Among the 10 various serovars different from SE and ST isolated in this study, S. Heidelberg, S. Agona and S. Hadar gave seropositive results in seven flocks. Consequently, this ELISA was not specific of SE and ST as it detected serovars sharing or not common antigens with SE and ST. Seropositive results were also obtained each month for two flocks where no Salmonella could be isolated. Finally, in seven flocks found infected with SE or ST, the positive ELISA results appeared later than the bacteriological detection. Therefore, for the detection of chicken flocks recently infected with SE or ST, bacteriological examination currently used in France seems to be more appropriate than this ELISA.

Some safety aspects of salmonella vaccines for poultry: distribution and persistence of three Salmonella typhimurium live vaccines.

The purpose of this study was to analyze the safety characteristics of three commercially available live Salmonella vaccine strains (vacT, Zoosaloral, and X3985) in relation to their persistence in individual animals but also within a flock and in the environment. In a first experiment, the digestive and systemic distributions in chickens were followed for 10 days in individually reared chickens that were orally inoculated at 1 day of age. Strain X3985 quickly disappeared from the digestive tract but remained in the liver until the end of this experiment, whereas strains vacT and Zoosaloral colonized the liver as well as the gut for 10 days. In the second trial, behavior of the vaccine strains was studied in groups of 20 chickens during 10 wk after a single oral administration to individual birds. Strain vacT remained in the environment of inoculated animals for 4-5 wk. Six weeks after the inoculation, vacT was not recovered from internal organs such as liver and spleen, and vacT disappeared from the digestive tract between the sixth and the 10th weeks. Comparatively, both Zoosaloral and X3985 vaccine strains persisted longer in the environment (8 wk at least). Of the vaccine strains, X3985 showed the greatest colonization of both systemic and digestive organs.

Bacteriological monitoring of Salmonella enteritidis carrier birds after decontamination using enrofloxacin, competitive exclusion and movement of birds.

Two hundred and forty, four-week-old laying birds naturally infected with Salmonella enteritidis PT33 (Pasteur Institute phage typing system) were randomly divided twice (before and during the treatments) to obtain four separately housed groups of 60 birds and to study the efficacy of three decontamination treatments: enrofloxacin either with or without the movement of birds to a clean area, and enrofloxacin combined with movement of birds and a competitive exclusion treatment. The control group remained untreated. In each group contamination with S enteritidis was checked bacteriologically, every week from two months before until two months after the treatments began. All the samples taken from all the birds before the treatments began were S enteritidis-positive. After the treatments it was not possible to isolate salmonella either from the environment or from the faeces of the three treated groups. All the birds were humanely sacrificed at 22 weeks of age and samples of liver, spleen, ovaries and caeca were analysed for the presence of salmonella. The results demonstrated that although antibiotic therapy, the movement of birds into a clean house and competitive exclusion, either combined or not, had some efficacy in reducing infection levels, it was not possible to decontaminate all the birds completely.

[Radiological aspects of hepatic tuberculoma. 3 cases]. / Aspects radiologiques du tuberculome hépatique. Trois cas.

Localized macronodular tuberculosis of the liver is rare. Tuberculous involvement of the liver is usually a diffuse process. We report 3 cases in which clinical and imaging features suggested the diagnosis of macronodular hepatic tuberculoma which was pathologically confirmed by percutaneous biopsy. In the first case, abdominal CT-scan showed a noncalcified hypodense nodular lesion in segment IV of the liver with an enhancing peripheral rim. In the second case, ultrasound showed 4 homogenous hypoechoic hepatic nodules. In the third case, a nodule was incidentally identified in segment VII of the liver. The lesion was hypoechoic with ultrasound, hypodense without enhancement on CT-scan, and hyperintense on both T1- and T2-weighted MR imaging. After percutaneous biopsy, pathologic examination showed peripheral granulomous lesions in all patients with central caseous necrosis consistent with tuberculosis in two patients despite a negative for Zielh stain. Specific M. tuberculosis culture was positive in the first patient, negative in the second patient, and was not performed in the third patient. Appropriate treatment resulted in disappearance of hepatic lesions on follow-up imaging examinations. These 3 cases show that clinical and imaging features of hepatic tuberculoma are not specific and that percutaneous biopsy of lesions provides a definite diagnosis.

[Serologic diagnosis of avian salmonelloses: adjustment of an ELISA test using antigens adsorbed with the aid of anti-colibacillary sera]. / Diagnostic sérologique des salmonelloses aviaires: mise au point d'un test ELISA utilisant des antigènes adsorbés à l'aide de sérums anticolibacillaires.

A serological ELISA test for diagnosis of avian salmonellosis infections with Salmonella typhimurium or enteritidis has been established. Plates were coated half with a negative antigen and half with a positive antigen. Both negative and positive antigens were adsorbed with a monovalent agglutinant anti Escherichia coli serum prior to being distributed into wells of the plates. Sera from SPF birds and from SPF birds vaccinated and/or inoculated with numerous viruses or bacteria, or sera from conventional birds bacteriologically free of any salmonellosis were tested and the percentage of false positive reactions was inferior than 1%. In groups of birds naturally infected or experimentally inoculated with Salmonella enteritidis or typhimurium the percentages of positive individuals were ranged from 15 to more than 90% according to the doses and routes of inoculation and the delay between contamination and sampling.

Use of a competitive exclusion product (Broilact) to prevent Salmonella colonization of newly hatched chicks.

The study described here was carried out at the request of a French company to utilize the authors' experience of 'competitive exclusion' treatment for poultry. The objective of the study was to determinate the safety and efficacy of a particular treatment product (Broilact) in protecting chicks against Salmonella infection.

Effect of four antibiotic additives on the Salmonella contamination of chicks protected by an adult caecal flora.

Avoparcin (10 mg/kg feed), bacitracin (50 mg/kg), flavomycin (5 mg/kg) and virginiamycin (20 mg/kg) were tested for their synergy or antagonism on the protective effect of an adult caecal flora administered to 1-day-old chicks. The chicks were challenged experimentally per os with 10(4) to 10(5)Salmonella typhimurium (a rifampicin-resistant strain) when aged 2 days. Chicks receiving avoparcin continuously in the feed had significantly more Salmonella in their caeca than control birds given feed containing no antibiotics; those receiving flavomycin had similar numbers to the controls whereas the groups fed on a diet supplemented with bacitracin or virginiamycin exhibited the lowest level of Salmonella carriage.

Colour vision impairment and alcohol consumption.

The relationship between alcohol intake and colour discrimination capacity was examined among 136 persons of whom 16 were undergoing treatment in a detoxification centre. Current weekly alcohol consumption (or prior to treatment for those in the centre) was obtained with a detailed questionnaire, which divided week and weekend drinking into types of alcohol (beer, wine, spirits). Alcohol consumption varied from 0-5824 g/week; median: 266 g/week. Qualitative and quantitative assessment of acquired dyschromatopsia was obtained with a colour arrangement test, the Lanthony D-15 desaturated panel. In all age categories, the prevalence of dyschromatopsia increased with alcohol intake. Moreover, all the heavy drinkers (greater than 751 g/week) presented a certain degree of dyschromatopsia, whether or not they were undergoing treatment for alcoholism in a detoxification centre. Colour loss was primarily in the blue-yellow range; however, 4 of the 16 persons from the detoxification centre presented complex dyschromatopsia patterns including red-green loss. This raises the question of possible progressive deterioration. Multiple regression analysis showed that colour vision loss was significantly related to both age (p less than 0.001) and alcohol intake (p less than 0.01). These results underline the importance of taking into account the contribution of alcohol consumption in studies on acquired dyschromatopsia.