Céline Dupuy

Defining syndromes using cattle meat inspection data for syndromic surveillance purposes: a statistical approach with the 2005-2010 data from ten French slaughterhouses.

BackgroundThe slaughterhouse is a central processing point for food animals and thus a source of both demographic data (age, breed, sex) and health-related data (reason for condemnation and condemned portions) that are not available through other sources. Using these data for syndromic surveillance is therefore tempting. However many possible reasons for condemnation and condemned portions exist, making the definition of relevant syndromes challenging.The objective of this study was to determine a typology of cattle with at least one portion of the carcass condemned in order to define syndromes. Multiple factor analysis (MFA) in combination with clustering methods was performed using both health-related data and demographic data.ResultsAnalyses were performed on 381,186 cattle with at least one portion of the carcass condemned among the 1,937,917 cattle slaughtered in ten French abattoirs. Results of the MFA and clustering methods led to 12 clusters considered as stable according to year of slaughter and slaughterhouse. One cluster was specific to a disease of public health importance (cysticercosis). Two clusters were linked to the slaughtering process (fecal contamination of heart or lungs and deterioration lesions). Two clusters respectively characterized by chronic liver lesions and chronic peritonitis could be linked to diseases of economic importance to farmers. Three clusters could be linked respectively to reticulo-pericarditis, fatty liver syndrome and farmer’s lung syndrome, which are related to both diseases of economic importance to farmers and herd management issues. Three clusters respectively characterized by arthritis, myopathy and Dark Firm Dry (DFD) meat could notably be linked to animal welfare issues. Finally, one cluster, characterized by bronchopneumonia, could be linked to both animal health and herd management issues.ConclusionThe statistical approach of combining multiple factor analysis with cluster analysis showed its relevance for the detection of syndromes using available large and complex slaughterhouse data. The advantages of this statistical approach are to i) define groups of reasons for condemnation based on meat inspection data, ii) help grouping reasons for condemnation among a list of various possible reasons for condemnation for which a consensus among experts could be difficult to reach, iii) assign each animal to a single syndrome which allows the detection of changes in trends of syndromes to detect unusual patterns in known diseases and emergence of new diseases.

Inventory of veterinary syndromic surveillance initiatives in Europe (Triple-S project): current situation and perspectives.

Within the current context that favours the emergence of new diseases, syndromic surveillance (SyS) appears increasingly more relevant tool for the early detection of unexpected health events. The Triple-S project (Syndromic Surveillance Systems in Europe), co-financed by the European Commission, was launched in September 2010 for a three year period to promote both human and animal health SyS in European countries. Objectives of the project included performing an inventory of current and planned European animal health SyS systems and promoting knowledge transfer between SyS experts. This study presents and discusses the results of the Triple-S inventory of European veterinary SyS initiatives. European SyS systems were identified through an active process based on a questionnaire sent to animal health experts involved in SyS in Europe. Results were analyzed through a descriptive analysis and a multiple factor analysis (MFA) in order to establish a typology of the European SyS initiatives. Twenty seven European SyS systems were identified from twelve countries, at different levels of development, from project phase to active systems. Results of this inventory showed a real interest of European countries for SyS but also highlighted the novelty of this field. This survey highlighted the diversity of SyS systems in Europe in terms of objectives, population targeted, data providers, indicators monitored. For most SyS initiatives, statistical analysis of surveillance results was identified as a limitation in using the data. MFA results distinguished two types of systems. The first one belonged to the private sector, focused on companion animals and had reached a higher degree of achievement. The second one was based on mandatory collected data, targeted livestock species and is still in an early project phase. The exchange of knowledge between human and animal health sectors was considered useful to enhance SyS. In the same way that SyS is complementary to traditional surveillance, synergies between human and animal health SyS could be an added value, most notably to enhance timeliness, sensitivity and help interpreting non-specific signals.

Prevalence of Taenia saginata cysticercosis in French cattle in 2010.

Bovine cysticercosis is a foodborne disease caused by the cestode Taenia saginata with cattle as the intermediate host and humans as the final host. This disease is responsible for direct financial losses for farmers. It is also economically important because human infestation through raw or undercooked meat consumption can have a negative impact on the confidence the consumer has in the food industry. This study aimed to determine the apparent and true prevalence of bovine cysticercosis in France and describe the locations of identified cysticercosis lesions. The study sample included 4,564,065 cattle slaughtered in 2010 in France, among which 6491 were detected as harbouring cysticercosis lesions using the current EU meat inspection process. The overall apparent prevalence (including both viable and degenerated cysticerci) was estimated at 0.142% [0.142-0.143]. The true overall prevalence defined as the estimation of the prevalence after taking into account the sensitivity of meat inspection (detection fraction) was 1.23% [0.83-1.93]. The true prevalence of cattle with at least one viable cysticercus was 0.113% [0.076-0.189]. Taking into account both our results and those of a previous study on the prevalence of human cysticercosis in France, we estimated that one carcass could infest an average of 8-20 individuals. The spatial distribution of viable cysticerci showed that the highest apparent prevalence was found in eastern France. This study, the largest survey ever conducted on bovine cysticercosis in France, indicated a low but spatially heterogeneous prevalence of the parasite among the cattle population. Considering French eating habits, according to which it is not uncommon to consume undercooked meat, the possibility of humans being infested even though viable cysticerci are not detected during meat inspection is high. Increasing the detection sensitivity of meat inspection through the use of a risk-based meat inspection procedure should improve prevention of human infestation.

Factors associated with offal, partial and whole carcass condemnation in ten French cattle slaughterhouses.

The proportion of cattle with offal, partial or whole carcass condemnation could be a useful indicator for animal health syndromic surveillance purposes. It requires first highlighting the factors associated with condemnation in order to include them in a modeling process. This study aims to identify and quantify these factors. It was based on data from ten French cattle slaughterhouses from 2006 to 2010 (n=1,439,868 cattle). Multivariable multinomial logistic regression analyses were performed. Sex, age and slaughterhouse were the main effects for offal, partial and whole carcass condemnation and have to be taken into account when implementing syndromic surveillance systems based on meat inspection data. The presence of an error in cattle identification was identified as a potential indicator for a higher risk of condemnation and should be explored as a potential factor for risk-based meat inspection.

A preliminary investigation of farm-level risk factors for cattle condemnation at the slaughterhouse: a case-control study on French farms.

The financial impact of condemnation for farmers and the importance of efficiency in the meat inspection process to guarantee food safety are well known. Identifying farm-level risk factors for condemnation are useful in order to find a way for farmers to potentially reduce their condemnation rates and to build a risk-based farm classification for veterinary services to target both meat inspection and farms inspections. To our knowledge, this has not yet been done, probably due to a lack of available meat inspection data. A preliminary investigation was performed through a case-control study on 36 French farms, from a dairy production region to identify farm-level risk factors for high condemnation rates (i.e. more than 45% of cattle with at least one portion of the carcass condemned). Multivariable exact logistic regression was performed to take into account the small sample size. The final model identified two significant risk factors. The odds of having a high condemnation rate was at least twice as greater for farmers who did not adhere to the quality charter of an international retailer and was significantly higher when the most qualified worker on the farm had a degree in agriculture. This latter effect was unexpected and is reviewed in the discussion section. The protective effect of the quality charter could be explained by the annual control of farms performed to guarantee compliance with good farming practices in the adhering farms. It led us to believe that compliance with well known good farming practices could be a way for farmers to reduce their condemnation rates. This study is a preliminary investigation performed on a small sample size of farms that were mainly dairy farms. It is a first step for further investigations that need to be done on this topic at a larger scale to fill the current lack of knowledge.

Construction of standardized surveillance indicators for bovine cysticercosis

Bovine cysticercosis is a zoonotic parasitic disease due to Cysticercus bovis. This study aimed to identify factors that could have an impact on the prevalence of cysticercosis and to use them to build standardized indicators of prevalence. Multivariate logistic regression analyses were performed on data from 4,564,065 cattle (91.3% of the cattle population slaughtered in France in 2010) among which 6491 cattle (0.14%) were found to harbor at least one lesion of cysticercosis (including 611 cattle harboring viable cysts, 0.01%). Two multivariate logistic models were fit to the data using as outcome variables either the presence or absence of viable cysts and the presence or absence of cysts whatever their level of development. Age and sex were identified as the main factors influencing bovine cysticercosis prevalence and were used for the construction of standardized prevalence and standardized cysticercosis rate. To illustrate the use of such indicators, they were calculated for the first and second semester of 2010 and for two different areas in France. The differences between raw prevalence and standardized prevalence highlight the use of standardized indicators for comparisons of prevalence between different areas and time periods as the structure of the slaughtered populations differ considerably from one to another.