Spatial-temporal Variations of Bovine Tuberculosis Incidence in France between 1965 and 2000.

We analysed the spatiotemporal variations of bovine tuberculosis (bTB) incidence between 1965 and 2000 in France at the department level (95 areas). Using a Bayesian space-time model, we studied the association between the evolution of bTB incidence and changes of cattle population structure and of herd management practices. Several spatiotemporal hierarchical Bayesian models were compared, and the deviance information criterion was used to select the best of them. Southern France remained a high-risk area over the analysed period, whereas central and western regions were low-risk areas. Besides the frequency of tuberculin skin testing (fixed according to bTB incidence in the preceding years), four factors were associated with an increased risk of bTB: the average herd density and size, the percentage of dairy cows in the cattle population, and the percentage of permanent grassland in cultivated surfaces area. These four factors are linked to the progressive professionalization and specialization of cattle farming, with the disappearance of family farms and of the intensification of breeding systems (especially in dairy farms after the application of the milk quota system in the 1980s). Both trends probably played a significant role in reducing the risk of bTB in France between 1965 and 2000, besides mandatory detection and control procedures.

The organisation and functioning of Veterinary Services: results of a 2005 survey of Member Countries of the World Organisation for Animal Health.

A questionnaire was sent to the 167 Member Countries of the World Organisation for Animal Health (OIE) in 2004 and 2005. The organisation and functioning of national Veterinary Services were analysed based on the responses from 85 of these countries. Leaving aside variations between countries, Veterinary Services are very involved in animal health and food safety controls at farm level (including animal feed), and during primary and secondary processing, whether alone or in conjunction with other services. At the lower end of the chain, namely distribution and the food service industry, responsibilities tend to be more widely shared. Veterinary Services have a central responsibility in international trade in animals and animal products. The main weaknesses in the chain of controls concern the logistical and financial resources of Veterinary Services, and insufficient involvement of livestock producers and even of field veterinarians. The many recent reforms are tending to provide a more consistent, integrated approach to animal health and food safety controls 'from the stable to the table'.

Quantitative risk assessment of human salmonellosis from the consumption of a turkey product in collective catering establishments.

The quantitative risk assessment (QRA) approach recommended by the Codex Alimentarius Commission was used to assess the risk of human salmonellosis from the consumption of 'cordon bleu', a specific turkey product, in collective catering establishments (CCEs) of a French department. The complete process was modeled and simulated, from the initial storage in the CCE freezer to the consumption, using a Monte Carlo simulation software. Data concerning the prevalence of contaminated 'cordon bleu', the level of contamination of Salmonella, the cooking and storage process were collected from 21 CCEs and 8 retailers of 'cordon bleu' in the selected department. Thermal inactivation kinetics for Salmonella were established to estimate the effect of heat treatment on the concentration in the product and to calculate the dose that could be ingested by the consumer. The Beta-Poisson dose-response model of Rose and Gerba [Water Science and Technology 24 (1991) 29] with the specific parameters for Salmonella was used to estimate the probability of infection related to the ingestion of a particular dose and a factor was applied to estimate the probability of illness from ingestion. The individual risk of salmonellosis, the risk of outbreak and the number of cases were calculated using Monte Carlo simulation method. The risk of salmonellosis was close to zero when the 'cordons bleus' were cooked in the oven. Therefore, the risk was calculated for the fryer cooking since the insufficient cooking time observed was, sometimes, at the origin of low temperatures (37-89 degrees C). The influence of both the initial concentration of Salmonella in the product and the heat storage before consumption on the final risk was studied. For a high initial concentration of Salmonella in the product, when the 'cordons bleus' are fryer cooked, the average risk of salmonellosis was equal to 3.95 x 10(-3) without storage before consumption and 2.8 x 10(-4) if the product is consumed after storage. This paper presents the results of the QRA and discusses risk management options to minimize the risk of salmonellosis.

Risk factors for false-positive serological reactions for bovine brucellosis in Saône-et-Loire (France).

Since 1990, unusually high rates of false-positive serological reactions (FPSR) in bovine brucellosis screening have been observed in some countries of the European Union. The aim of this survey was to describe this phenomenon in a highly affected French Department, and to evaluate the links between some individual or herd factors and the occurrence of these FPSR. Before 1990, low backgrounds of FPSR were recorded (individual prevalence rate: less than 0.5 per 10,000). The phenomenon burst during the 1990-91 screening campaign, reached a peak in 1992-93 (50.5 per 10,000), and then decreased until the last studied campaign, 1995-96 (9.1 per 10,000). The phenomenon was transient and sporadic within a herd. At the herd-screening level, four assumed risk factors were isolated: (i) the probability of a herd-screening to be positive was closely and positively linked with the herd screening size; (ii) during a given screening campaign, the prevalence of FPSR decreased from December to November; (iii) the presence of at least one goat on the premises increased the risk for the 1992-93 and 1993-94 screening campaigns; and (iv) a previous FPSR in a given herd appeared to be a weak but significant risk factor. At the individual-animal level, herd size, sex and breed did not seem to be linked with FPSR appearance, while young animals were significantly more affected than older ones. However, global variations in herd or individual prevalences remained unexplained. The lack of link between FPSR and brucellosis is strengthened. The hypothesis of a widely spread causal agent with a low individual host susceptibility and/or a low probability of detecting FPSR animals can be supported by these results.

[Methodology of surveys in animal epidemiology]. / Méthodologie des enquêtes en épidémiologie animale.

In the present paper, the authors review the methodological bases of surveys, both descriptive and analytical, used in animal epidemiology. They give a comprehensive definition of the main terms applied to epidemiology as well as of the method used to evaluate the quality of these surveys.

Comparison of performances of four ELISA kits in the detection of BLV antibodies in bulk tank milk or concentrated lactoserum from herds with low prevalence of infection.

Performances of four ELISA kits in the detection of BLV antibodies in bulk tank milk was studied in 76 non-infected herds and 44 herds with low prevalence of BLV infection. None of the kits gave false positive results. On the other hand, there was an important variation in sensitivity. The kits with the highest sensitivity identified 43% of infected herds, which included 65% of infected cows. When concentrated lactoserum was tested, 59% of infected herds, which included 73% of infected cows, could be identified.

Detection of bovine leukemia virus antibodies in bulk tank milk using an ELISA test: improvement of the predictive value of results by repeated testing.

In 9457 dairy farms located in an area with low prevalence of bovine leukemia virus (BLV) infection, bulk tank milk was examined to detect for the presence of antibodies using an ELISA test. If the result was positive or doubtful, serum of all animals in the farm was tested and bulk tank milk was tested again five times every 8-12 days. The results were used to establish decision rules in the event of a positive or doubtful result during mass screening.