The French Epidemic Intelligence System: comparing disease surveillance at the national and international level using data from the Program for Monitoring Emerging Diseases.

In a context of globalisation and climate change, the risk of emerging infectious diseases spreading around the world has significantly increased in the past decades. In response to this growing threat, an epidemic intelligence team has been set up within the framework of the French animal health epidemiological surveillance platform (ESA platform). The French Epidemic Intelligence System (FEIS) monitors animal health risks in Europe and beyond that threaten animal populations in France (emerging and exotic diseases not yet present). The FEIS expert network covers all 53 category 1 health hazards identified as priority diseases by the French authorities. From January 2016 to December 2017, the FEIS published 126 reports on animal health events related to infectious diseases, of which 76.2% were related to events in Europe. When comparing FEIS reports to posts from the Program for Monitoring Emerging Diseases (ProMED), an FEIS report was produced for 52.6% of ProMED themes (combinations of disease and country) posted in 2016-2017 on events in Europe. The remaining European ProMED themes did not meet the criterion for the production of an FEIS report because either the disease was already present in France, the risk of introduction into France was considered low or negligible, or the introduction of the pathogen would have low or negligible economic and societal impacts. The FEIS efficiently detected and reported on all health hazards identified by ProMED to alert health authorities and stakeholders when needed (according to the criterion). Compared with international epidemic intelligence systems such as ProMED, which provide general information, the FEIS adds another layer of filtering and interpretation to available information on animal health threats tailored to France's specific needs, in order to communicate only essential information to health authorities.

Dans un contexte caractérisé par la mondialisation et le changement climatique, le risque de propagation mondiale des maladies infectieuses émergentes s'est significativement accru en quelques décennies. Pour répondre à cette menace croissante, une équipe de veille épidémique a été mise en place dans le cadre de la Plateforme française d'épidémiosurveillance en santé animale (Plateforme ESA). Le système de Veille sanitaire internationale (VSI) surveille les risques sanitaires en santé animale présents en Europe, voire au-delà, dès lors qu'ils représentent une menace pour les populations animales sur le territoire français (maladies émergentes et maladies exotiques jamais introduites en France). Le réseau d'experts de la VSI couvre les 53 risques sanitaires de catégorie 1 définis par les autorités françaises comme maladies prioritaires. De janvier 2016 à décembre 2017, 126 rapports de la VSI ont été publiés sur des événements de santé animale liés à des maladies infectieuses, dont 76,2 % concernaient des événements survenus en Europe. La comparaison entre les rapports émanant de la VSI et ceux du Programme de suivi des maladies émergentes (ProMED) fait apparaître que 52,6 % des thématiques publiées en 2016-2017 par ProMED (associant une maladie et un pays) relatives à des événements survenus en Europe avaient également fait l'objet d'un rapport par la VSI. Les thématiques restantes sur ProMED correspondant à des événements européens ne répondaient pas aux critères de la VSI, soit parce qu'il s'agissait d'une maladie déjà présente en France, soit parce que le risque d'introduction de l'agent pathogène en France était considéré comme faible ou négligeable, soit enfin parce que l'impact économique et sociétal d'une telle introduction, si elle survenait, aurait été faible ou négligeable. La VSI a détecté (en fonction de ses critères) l'ensemble des risques sanitaires identifiés par ProMED et les a notifiés avec efficacité aux autorités et acteurs en charge de la santé, chaque fois que nécessaire. Par rapport aux systèmes de veille sanitaire internationaux tels que ProMED qui fournissent des informations générales, la VSI, qui est spécifiquement adaptée aux besoins français, ajoute une strate supplémentaire de filtrage et d'interprétation des données disponibles sur les menaces de santé animale, afin de ne transmettre aux autorités sanitaires que les informations qui leur sont essentielles.

De unos decenios a esta parte, en un contexto marcado por la mundialización y el cambio climático, ha aumentado sustancialmente el riesgo de propagación por todo el mundo de enfermedades infecciosas emergentes. Para responder a esta creciente amenaza se ha establecido, dentro del dispositivo francés de vigilancia epidemiológica zoosanitaria (plataforma ESA), un equipo de inteligencia epidemiológica. El Sistema Francés de Información Epidemiológica (épidémiologique) está dedicado a seguir de cerca los riesgos zoosanitarios que, desde Europa u otras partes del mundo, amenacen a las poblaciones animales de Francia (enfermedades emergentes y exóticas que aún no estén presentes en el país). La red de especialistas de la VSI cubre la totalidad de los 53 peligros sanitarios de categoría 1 que las autoridades francesas tienen definidos como enfermedades prioritarias. Entre enero de 2016 y diciembre de 2017, la VSI publicó 126 informes sobre episodios zoosanitarios relacionados con enfermedades infecciosas, de los que un 76,2% tenían que ver con episodios ocurridos en Europa. Al comparar los informes de la VSI con las notas publicadas por el Programa de Vigilancia de Enfermedades Emergentes (ProMED) se constató que ela VSI había elaborado un informe en relación con el 52,6% de los temas (combinación de enfermedades y países) tratados por el ProMED en sus notas de 2016 y 2017 sobre episodios ocurridos en suelo europeo. Los restantes temas europeos tratados por el ProMED no cumplían el criterio de que hubiera un informe de la VSI al respecto, ya fuera porque la enfermedad ya estaba presente en Francia, porque se consideró bajo o insignificante el riesgo de penetración en Francia o porque la llegada del patógeno tendría una repercusión escasa o insignificante en la economía o la sociedad. La VSI detectó y comunicó con eficacia todos los peligros sanitarios identificados por el ProMED para alertar a las autoridades sanitarias y demás interlocutores cada vez que fue necesario (con arreglo al criterio). En comparación con los sistemas internacionales de información epidemiológica, como el ProMED, que proporcionan información general, la VSI agrega un filtro y un nivel de interpretación suplementarios a la información disponible sobre amenazas zoosanitarias, adaptándola así a las necesidades específicas de Francia, con el fin de comunicar únicamente información esencial a las autoridades sanitarias.

Estimation of French cattle herd immunity against bluetongue serotype 8 at the time of its re-emergence in 2015.

BACKGROUND: From 2006 to 2010, France experienced two bluetongue epidemics caused by serotype 1 (BTV-1) and 8 (BTV-8) which were controlled by mass vaccination campaigns. After five years without any detected cases, a sick ram was confirmed in August 2015 to be infected by a BTV-8 strain almost identical to that circulating during the previous outbreak. By then, part of the French cattle population was expected to be still protected, since bluetongue antibodies are known to last for many years after natural infection or vaccination. The objective of this study was to estimate the proportion of cattle in France still immune to BTV-8 at the time of its re-emergence in 2015. RESULTS: We used BTV group-specific cELISA results from 8525 cattle born before the vaccination ban in 2013 and 15,799 cattle born after the ban. Samples were collected from January to April 2016 to estimate seroprevalence per birth cohort. The overall seroprevalence in cattle at national and local levels was extrapolated from seroprevalence results per birth cohort and their respective proportion at each level. To indirectly assess pre-immune status of birth cohorts, we computed prevalence per birth cohort on infected farms in autumn 2015 using 1377 RT-PCR results. These revealed limited BTV circulation in 2015. Seroprevalence per birth cohort was likely to be connected to past exposure to natural infection and/or vaccination with higher seroprevalence levels in older animals. A seroprevalence of 95% was observed for animals born before 2008, of which > 90% were exposed to two compulsory vaccination campaigns in 2008-2010. None of the animals born before 2008 were found to be infected, unlike 19% of the young cattle which had never been vaccinated. This suggests that most ELISA-positive animals were pre-immune to BTV-8. We estimated that 18% (from 12% to 32% per département) of the French cattle population was probably pre-immune in 2015. CONCLUSIONS: These results strongly suggest a persistence of antibodies for at least 5-6 years after natural infection or vaccination. The herd immunity of the French cattle population probably limited BTV circulation up to 2015, by which time more than 80% of cattle were naive.

Review of bovine brucellosis surveillance in Europe in 2015.

Bovine brucellosis is a major zoonosis and is responsible for significant reproductive disorders and production losses in cattle. Surveillance and control are regulated at the European level with specific conditions to obtain and maintain the officially free status, which facilitates access to export markets. These European standards allow for harmonisation in brucellosis surveillance and diagnosis while leaving some flexibility to countries in the choice of measures to meet the desired objectives. This study reviews the bovine brucellosis surveillancesystems currently in place across the European continent, according to countries' brucellosis status, based on a survey addressed to brucellosis diagnosis expertsin the National Reference Laboratory of each country. Experts were asked toprovide synthesised surveillance data and to describe technical conditions andscreening tests carried out for the surveillance of abortions, serological testing inherds, movement controls and any other surveillance components in 2015. Results were obtained for 34 out of 37 countries (92%). Surveillance systems included abortion surveillance (34 countries), routine herd screening (28 countries), movement testing (14 countries), routine testing at bull stations (9 countries),and screening tests at slaughterhouses (4 countries). The review highlighted variability in technical conditions and screening tests among countries. These results are discussed with regard to the European Union regulations, disease risks and epidemiological situations, with the aim of improving surveillance efficacy and efficiency.

La brucellose bovine est une zoonose majeure qui entraîne chez les bovins de graves troubles de la reproduction ainsi qu'une baisse importante de la production. La surveillance et le contrôle de cette maladie font l'objet d'une réglementation spécifique au niveau européen, à travers des dispositions conditionnant l'obtention et le maintien du statut officiel indemne, lequel facilite l'accès aux marchés d'exportation. Les normes européennes permettent d'harmoniser la surveillance et le diagnostic de la brucellose tout en laissant aux pays une certaine marge de manoeuvre quant au choix des mesures appliquées pour atteindre les objectifs souhaités. En se basant sur les résultats d'une enquête conduite auprès des experts des Laboratoires de référence nationaux pour le diagnostic de la brucellose dans chaque pays, les auteurs font le point sur les systèmes de surveillance de la brucellose bovine appliqués actuellement en Europe en fonction du statut des pays au regard de la brucellose. Il a été demandé aux experts de présenter une synthèse des données de surveillance et de décrire le dispositif technique de suivi et les tests de dépistage effectués en cas d'avortement, ainsi que la surveillance sérologique conduite à l'échelle des troupeaux, les contrôles exercés sur les mouvements d'animaux et toute autre composante de la surveillance en 2015. Au total, 34 des 37 pays interrogés (92 %)ont répondu à l'enquête. Les systèmes de surveillance en place portaient sur les points suivants : surveillance des avortements (34 pays), dépistage systématique à l'échelle des troupeaux (28 pays), tests sur les animaux déplacés (14 pays), dépistage systématique dans les stations de monte et les taurelleries (neuf pays) et dépistage à l'abattoir (quatre pays). Les résultats de l'enquête mettent en relief la diversité du contexte technique et des tests de dépistage d'un pays à l'autre. Les auteurs analysent ces résultats au regard de la réglementation de l'Union européenne, des risques sanitaires spécifiques et des diverses situations épidémiologiques, dans le but d'améliorer l'efficacité et l'efficience de la surveillance.

La brucelosis bovina es una importante zoonosis, causante de graves trastornos reproductivos y de cuantiosas pérdidas en el sector de la producción pecuaria. En los reglamentos europeos, que rigen las actividades de vigilancia y control, se establecen también requisitos específicos para obtener y mantener el estatutode «oficialmente libre de la enfermedad¼, que facilita el acceso a los mercados de exportación. Estas normas europeas permiten armonizar las actividades devigilancia y diagnóstico de la brucelosis y ofrecer a la vez cierta flexibilidad alos países en la elección de las medidas necesarias para cumplir los objetivos fijados. Los autores pasan revista a los sistemas de vigilancia de la brucellosis bovina actualmente implantados en todo el continente europeo, en funcióndel estatuto del país con respecto a la enfermedad, utilizando para ello los datosde un cuestionario dirigido a los especialistas en diagnóstico de la brucelosis decada laboratorio nacional de referencia. A cada uno se le pedía una síntesis delos datos de vigilancia y una descripción (incluidas las condiciones técnicas) delas pruebas de detección realizadas con fines de vigilancia de abortos, análisis serológico de rebaños, controles en caso de movimiento de animales y demás componentes de la vigilancia que se hubieran aplicado en 2015. Se obtuvieron así datos de 34 países sobre un total de 37 (un 92%). Los sistemas de vigilancia descritos incluían la vigilancia de abortos (34 países), la realización sistemática de pruebas de detección en rebaños (28 países), en corrales de toros (nueve países) y en mataderos (cuatro países) y la realización de pruebas antes y/o después del movimiento de animales (14 países). El estudio puso de manifiesto la heterogeneidad reinante entre los países en cuanto a las pruebas de detección practicadas y a sus condiciones técnicas. Los autores examinan esos resultados en relación con las normas de la Unión Europea, los riesgos de enfermedad y las situaciones epidemiológicas, con el objetivo de conferir más eficacia y eficiencia a las labores de vigilancia.

Estimation of the frequency of Q fever in sheep, goat and cattle herds in France: results of a 3-year study of the seroprevalence of Q fever and excretion level of Coxiella burnetii in abortive episodes.

A study was carried out, from 2012 to 2015, in 10 French départements to estimate the serological prevalence of Q fever and the frequency of abortive episodes potentially related to Coxiella burnetii in a large sample of cattle, sheep and goat herds. The serological survey covered 731 cattle, 522 sheep and 349 goat herds, randomly sampled. The frequency of abortive episodes potentially related to C. burnetii was estimated by investigating series of abortions in 2695 cattle, 658 sheep and 105 goat herds using quantitative polymerase chain reaction analyses and complementary serological results when needed. The average between-herd seroprevalence was significantly lower for cattle (36·0%) than for sheep (55·7%) and goats (61·0%) and significantly higher for dairy herds (64·9% for cattle and 75·6% for sheep) than for meat herds (18·9% for cattle and 39·8% for sheep). Within-herd seroprevalence was also significantly higher for goats (41·5%) than for cattle (22·2%) and sheep (25·7%). During the study period, we estimated that 2·7% (n = 90), 6·2% (n = 48) and 16·7% (n = 19) of the abortive episodes investigated could be 'potentially related to C. burnetii'in cattle, sheep and goat herds, respectively. Overall, strong variability was observed between départements and species, suggesting that risk factors such as herd density and farming practices play a role in disease transmission and maintenance.

Pilot simulation study using meat inspection data for syndromic surveillance: use of whole carcass condemnation of adult cattle to assess the performance of several algorithms for outbreak detection.

The objective of this study was to assess the performance of several algorithms for outbreak detection based on weekly proportions of whole carcass condemnations. Data from one French slaughterhouse over the 2005-2009 period were used (177 098 slaughtered cattle, 0.97% of whole carcass condemnations). The method involved three steps: (i) preparation of an outbreak-free historical baseline over 5 years, (ii) simulation of over 100 years of baseline time series with injection of artificial outbreak signals with several shapes, durations and magnitudes, and (iii) assessment of the performance (sensitivity, specificity, outbreak detection precocity) of several algorithms to detect these artificial outbreak signals. The algorithms tested included the Shewart p chart, confidence interval of the negative binomial model, the exponentially weighted moving average (EWMA); and cumulative sum (CUSUM). The highest sensitivity was obtained using a negative binomial algorithm and the highest specificity with CUSUM or EWMA. EWMA sensitivity was too low to select this algorithm for efficient outbreak detection. CUSUM's performance was complementary to the negative binomial algorithm. The use of both algorithms on real data for a prospective investigation of the whole carcass condemnation rate as a syndromic surveillance indicator could be relevant. Shewart could also be a good option considering its high sensitivity and simplicity of implementation.

Veterinarians as practitioners and as key players in epidemiological surveillance: two tasks, two paradigms to be reconciled.

Veterinary practitioners are often involved in epidemiological surveillance systems, where their task is to detect animals suspected of suffering from diseases subject to surveillance and to include them in surveillance. However, these two tasks--practising veterinary medicine and taking part in surveillance--are based on different paradigms. Faced with a sick animal, a practitioner tries to maximise the probability of a correct diagnosis, whereas, when implementing surveillance, a veterinarian is required to maximise the inclusion of suspected cases in surveillance systems. Based on an analysis of the difficulties and problems posed by these coexisting tasks, the authors propose potential solutions through veterinary education and training. The implementers and coordinators of epidemiological surveillance systems must take these factors into account.

First insights into Puumala orthohantavirus circulation in a rodent population in Alsace, France.

In-depth knowledge on the mechanisms that maintain infection by a zoonotic pathogen in an animal reservoir is the key to predicting and preventing transmission to humans. The Puumala orthohantavirus (PUUV), the most prevalent orthohantavirus in Western Europe, causes a mild form of haemorrhagic fever with renal syndrome (HFRS) in humans. In France, this endemic illness affects the north-eastern part of the country. We conducted a 4-year capture-mark-recapture study in a bank vole population, combined with molecular analyses, to explore the epidemiological situation of PUUV in Alsace, a French region where human cases have occurred, but for which no studies have been conducted on this reservoir host. PUUV-infected bank voles were detected in the 2 years that showed high bank vole density with a prevalence of 4%. The individual PUUV sequences identified in this study were similar from year to year and similar to other French sequences. On a very small spatial scale, the distribution of seropositive bank voles was very heterogeneous in time and space. The short distances travelled on average by bank voles resulted in spatial clusters of seropositive rodents, which spread only very gradually throughout the year.

Spread rate of lumpy skin disease in the Balkans, 2015-2016.

After its introduction in Turkey in November 2013 and subsequent spread in this country, lumpy skin disease (LSD) was first reported in the western Turkey in May 2015. It was observed in cattle in Greece and reported to the World Organization for Animal Health (OIE) in August 2015. From May 2015 to August 2016, 1,092 outbreaks of lumpy skin disease were reported in cattle from western Turkey and eight Balkan countries: Greece, Bulgaria, The Former Yugoslav Republic of Macedonia, Serbia, Kosovo, and Albania. During this period, the median LSD spread rate was 7.3 km/week. The frequency of outbreaks was highly seasonal, with little or no transmission reported during the winter. Also, the skewed distribution of spread rates suggested two distinct underlying epidemiological processes, associating local and distant spread possibly related to vectors and cattle trade movements, respectively.

Milk yield, age at first calving, and the risk of BSE: an analysis at the farm level in France.

The epidemic of bovine spongiform encephalopathy (BSE) in France, as in the UK, has affected dairy cattle much more than beef cattle. However, the intensification of dairy herd management as a risk factor for BSE has not to date been analyzed. For this purpose, two databases were merged: the French Milk Records database, and the French BSE database, which can be considered as being devoid of notification bias since July 2001, when systematic tests were implemented. Only pure Holstein herds were considered, which represent the vast majority of total and BSE-affected dairy herds in France. A case-control study was designed so that 20 control herds were matched to each case herd according to the location of the farm and the year of birth of the index case. Three thousand and forty five farms were included, among which 145 with a BSE case notified between July 2001 and July 2003, and 2900 controls. With respect to the risk of BSE, odds ratios for each class of milk yield and age at first calving were estimated by using conditional logistic regression models with appropriate adjustments to herd size. The two main results were the following: firstly, whereas most Holstein herds, with average production between 7000 and 10,000kg, had nearly the same BSE risk, a small category of very intensive herds, with annual milk yields above 10,000kg, were significantly more at risk than the other herds. Secondly, a very early first calving (under 26 months of age) was found to be at risk for BSE as compared to other categories, independently of the milk yield. These results are discussed in the light of the known age-dependent susceptibility to BSE.

A study of the knowledge, attitudes, and behaviors of French dairy farmers toward the farm register.

Health organizations worldwide have advocated that treatment records be required to show that antibiotics are used prudently by veterinarians and farmers alike. In 2000, the French government passed legislation making a farm register mandatory for all farms that raise animals for food production. The farm register is a comprehensive record designed to track all animal movements, treatments, and veterinary interventions on the farm. We conducted a survey to assess the knowledge, attitudes, and behaviors of dairy farmers toward the farm register, with particular emphasis on recording of antibiotic treatments. The 43 farmers interviewed belonged to veterinary health cooperatives. All farmers correctly named an antibiotic or antibiotic preparation, yet only 2 recognized the 5 components of the farm register. Farmer attitudes toward the register were globally positive, even though they named a wide variety of constraints. Nevertheless, 72% of farmers interviewed had a permanent health record, and approximately half had recorded either the last treatment (irrespective of drug class) or the last intramammary tube administered. Results were discussed in the light of health behavior change models that are applied in human medicine. We suggest that programs that seek compliance with the farm register should focus on educational interventions and bonus incentives.

Fallen stock data: An essential source of information for quantitative knowledge of equine mortality in France.

BACKGROUND: Quantitative information about equine mortality is relatively scarce, yet it could be of great value for epidemiological purposes. In France, data from rendering plants are centralised in the Fallen Stock Data Interchange database (FSDI), managed by the French Ministry of Agriculture, while individual equine data are centralised in the French equine census database, SIRE, managed by the French horse and riding institute (IFCE). OBJECTIVES: To evaluate whether the combined use of the FSDI and SIRE databases can provide representative and accurate quantitative information on mortality for the French equine population and to propose enhancements of these databases to improve the quality of the resulting demographic information. STUDY DESIGN: Descriptive study. METHODS: Mortality ratios for the French equine population were calculated per year between 2011 and 2014 and temporal variations in equine mortality modelled during the same period. Survival analyses were performed on a sample of equines traceable in both the FSDI and SIRE databases. RESULTS: Estimates of the annual mortality ratios varied from 3.02 to 3.40% depending on the years. Survival rates of equines 2-years-old and over differed according to breed categories with the highest median age at death for the ponies. The weekly description of mortality highlighted marked seasonality of deaths whatever the category of equines. Modelling temporal variations in equine mortality also brought to light excess mortality. MAIN LIMITATIONS: Insufficient traceability of equines between the two databases. CONCLUSION: The FSDI database provided an initial approach to equine death ratios on a national scale and an original description of temporal variations in mortality. Improvement in the traceability of equines between the FSDI and SIRE databases is needed to enable their combined use, providing a representative description of equine longevity and a more detailed description of temporal variations in mortality.

Spatial and Temporal Epidemiology of Nephropathia Epidemica Incidence and Hantavirus Seroprevalence in Rodent Hosts: Identification of the Main Environmental Factors in Europe.

In Europe, the increasing number of nephropathia epidemica (NE) infections in humans, caused by Puumala virus carried by bank voles (Myodes glareolus), has triggered studies of environmental factors driving these infections. NE infections have been shown to occur in specific geographical areas characterized by environmental factors that influence the distribution and dynamics of host populations and virus persistence in the soil. Here, we review the influence of environmental conditions (including climate factors, food availability and habitat conditions) with respect to incidence in humans and seroprevalence in rodents, considering both direct and indirect transmission pathways. For each type of environmental factor, results and discrepancies between studies are presented and examined in the light of biological hypotheses. Overall, food availability and temperature appear to be the main drivers of host seroprevalence and NE incidence, but data quality and statistical approaches varied greatly among studies. We highlight the issues that now need to be addressed and suggest improvements for study design in regard to the current knowledge on hantavirus epidemiology.

Estimates of the prevalence of transmissible spongiform encephalopathies in sheep and goats in France in 2002.

An active surveillance programme for transmissible spongiform encephalopathies (TSES) in sheep and goats was implemented in France in 2002 at abattoirs and rendering plants. The analysis of the results of this programme highlighted three biases: a potentially non-random sampling scheme in both rendering plants and abattoirs, a heterogeneous geographical sampling ratio, and the use of two diagnostic tests of unequal sensitivity. Simulations were run to estimate the prevalence of TSES by taking these biases into account. A comparison of the prevalence of TSES calculated from the raw data with the simulation results showed that the effects of non-random sampling were minor in comparison with the effects of the heterogeneous geographical sampling ratio and the use of two diagnostic tests.

Identifying Areas Suitable for the Occurrence of Rift Valley Fever in North Africa: Implications for Surveillance.

Rift Valley fever (RVF) is a vector-borne zoonotic disease that has caused widespread outbreaks throughout Africa and the Arabian Peninsula, with serious consequences for livestock-based economies and public health. Although there have never been any reports of RVF in Morocco, Algeria, Tunisia and Libya, it is a priority disease in the Maghreb, due to the threat of introduction of the virus through transboundary livestock movements or infected mosquito vectors. However, the implementation of surveillance activities and early warning contingency plans requires better knowledge of the epidemiological situation. We conducted a multicriteria decision analysis, integrating host distribution with a combination of important ecological factors that drive mosquito abundance, to identify hotspots and suitable time periods for RVF enzootic circulation (i.e. stable transmission at a low to moderate level for an extended period of time) and an RVF epizootic event (i.e. a sudden occurrence of a large number of infected animals over a large geographic area) in the Maghreb. We also modelled vector species distribution using available information on vector presence and habitat preference. We found that the northern regions of the Maghreb were moderately suitable for RVF enzootics, but highly suitable for RVF epizootics. The vector species distribution model identified these regions as the most favourable mosquito habitats. Due to the low density of animal hosts and arid conditions, the desert region showed low RVF suitability, except in oases. However, the presence of competent vectors in putative unsuitable areas underlines the need for further assessments of mosquito habitat preference. This study produced monthly RVF suitability maps useful for animal health managers and veterinary services involved in designing risk-based surveillance programmes. The suitability maps can be further enhanced using existing country-specific sources of information and by incorporating knowledge - as it becomes available - on the epidemiology of the disease and distribution of vectors in the Maghreb.

Past, present and future of bovine spongiform encephalopathy in France.

The bovine spongiform encephalopathy (BSE) epidemic has been monitored in France since the end of 1990. The surveillance has been considerably enhanced since 2000, and today every cow aged 2 years or more is tested at the time of slaughter, culling or death. As of 1 May 2002, 613 native cases have been identified, 287 of them by the mandatory reporting system of suspect clinical cases or complementary programs, 213 by active surveillance of fallen stock and 113 by testing at the abattoir. The analysis of reported BSE cases shows a higher number of cases born between 1993 and 1995, which can be linked to a greater exposure at that time and to an increase in surveillance efficiency. When the clinical onset related to overexposure ends, the future trend of the BSE epidemic in France will depend on the efficiency of the control measures implemented since 1996. An indicator of this will be the number of BSE cases born among recent cohorts. Bovine spongiform encephalopathy (BSE) was described first in 1987 in Great Britain (Wells et al. 1987), where a huge epidemic started, and more than 180,000 cases have been detected since then in this country. A risk analysis undertaken in France in 1990, in part because of the amount of meat and bone meal (MBM) imported from Great Britain during the 1980s, led to the conclusion that BSE might have spread to France, and that sporadic cases might be observed (Savey et al. 1991). Epidemiological surveillance was therefore set up at the end of 1990, and control measures were taken to prevent the development of the disease. The trends in the number of BSE cases detected in France must be analyzed in the light of both the detection system and the control measures, as well as their changes over time.

Syndromic surveillance of abortions in beef cattle based on the prospective analysis of spatio-temporal variations of calvings.

Our objective was to study the ability of a syndromic surveillance system to identify spatio-temporal clusters of drops in the number of calvings among beef cows during the Bluetongue epizootic of 2007 and 2008, based on calving seasons. France was partitioned into 300 iso-populated units, i.e. units with quite the same number of beef cattle. Only 1% of clusters were unlikely to be related to Bluetongue. Clusters were detected during the calving season of primary infection by Bluetongue in 28% (n = 23) of the units first infected in 2007, and in 87% (n = 184) of the units first infected in 2008. In units in which a first cluster was detected over their calving season of primary infection, Bluetongue was detected more rapidly after the start of the calving season and its prevalence was higher than in other units. We believe that this type of syndromic surveillance system could improve the surveillance of abortive events in French cattle. Besides, our approach should be used to develop syndromic surveillance systems for other diseases and purposes, and in other settings, to avoid "false" alarms due to isolated events and homogenize the ability to detect abnormal variations of indicator amongst iso-populated units.

Sensitivity of the Western blot detection of prion protein PrPres in natural sheep scrapie.

The sensitivity of Western blot detection of PrPres using two different extraction procedures on brain material of 30 scrapie-affected sheep was compared. Whereas PrPres could be detected in all sheep after extraction with the first method, 30% did not give any signal after extraction with the second method. However, the second method, when positive, permitted the detection of PrPres from smaller amounts of infected brain tissue. When used with the ruminant specific monoclonal antibody p4, the second method gave positive signals corresponding to less than 12.5 microg of scrapie-infected brain, that, up to now, is the highest sensitivity described for PrPres detection from naturally infected ruminant brains. The overall results showed highly variable levels of PrPres between sheep and are presented in relation to breed, survival time and animal genotype data. Further progress can thus be expected for PrPres detection in prion diseases, if more efficient extraction procedures and more sensitive immunological reagents are used. Such technical improvements could contribute to more accurate diagnosis in animals affected naturally.

Comparison of French natural scrapie isolates with bovine spongiform encephalopathy and experimental scrapie infected sheep.

We compared the glycoform pattern of the abnormal prion protein (PrP(Sc)) detected by immunoblotting in 21 sheep with natural scrapie, from 21 different outbreaks identified in France since 1996, with a bovine spongiform encephalopathy (BSE)-infected sheep. All the natural scrapie isolates had a higher molecular mass of the unglycosylated PrP(Sc) than in BSE-infected sheep. In the latter case, this molecular mass appeared identical to that found in the CH 1641 experimental scrapie strain (type C pattern), whereas in natural scrapie cases it was similar to that found in the SSBP/1 experimental scrapie strains. These results suggest that all French natural scrapie isolates studied so far would belong, as SSBP/1, to the group of scrapie cases with type A electrophoretic pattern.

Efficacy of spectinomycin against Mycoplasma bovis induced pneumonia in conventionally reared calves.

Sixteen 3-week-old calves were intratracheally inoculated with Mycoplasma bovis. Follow-up consisted of regular bronchoalveolar lavages (BALs) and clinical examinations. Animals were slaughtered from 4 to 21 days after inoculation. Counts were made of the mycoplasmas and other bacteria systematically isolated from the BAL liquids and lung lobes after slaughter. On the 6th day, spectinomycin 20mg/kg was given intramuscularly in three repeated doses at 24h intervals to six randomly chosen calves. All animals had developed a persistent M. bovis infection with a maximum BAL count on the 6th day (start of treatment). Co-occuring Pasteurella multocida infection was found in most animals with a maximum rate on the 14th day. The extent of lung surface lesions varied widely (0-64%) but was greater in the later slaughtered calves. Average counts of M. bovis and P. multocida in the BAL liquids were lower in treated calves than in untreated ones but the difference was not statistically significant. However, M. bovis and P. multocida counts in the lungs of the treated group were significantly lower than in the untreated group (p=0.003 and 0.009, respectively).

Qualitative interaction between the observer and the observed in veterinary epidemiology.

The phenomenon of qualitative interaction between the research activity and the studied object exists in veterinary epidemiology, as in all observation-based disciplines. Observational studies carried out under farm conditions strongly involve the farmers and the farm's usual advisors in the data collection. This leads to various biological and sociological interactions between the observer and the observed that can modify the results of the study. Some methodological considerations are proposed in order to consider such qualitative interaction, from the designing of the study through to the interpretation of the results. Examples are presented to illustrate these ideas.