Pascal Hendrikx

Epidemiology, molecular virology and diagnostics of Schmallenberg virus, an emerging orthobunyavirus in Europe

After the unexpected emergence of Bluetongue virus serotype 8 (BTV-8) in northern Europe in 2006, another arbovirus, Schmallenberg virus (SBV), emerged in Europe in 2011 causing a new economically important disease in ruminants. The virus, belonging to the Orthobunyavirus genus in the Bunyaviridae family, was first detected in Germany, in The Netherlands and in Belgium in 2011 and soon after in the United Kingdom, France, Italy, Luxembourg, Spain, Denmark and Switzerland. This review describes the current knowledge on the emergence, epidemiology, clinical signs, molecular virology and diagnosis of SBV infection.

Preliminary estimate of Schmallenberg virus infection impact in sheep flocks – France

Schmallenberg virus (SBV) infection is an emerging livestock disease caused by a novel Orthobunyavirus which was first identified in Germany in November 2011. Non-specific clinical signs such as fever, decreased milk production and diarrhoea are associated with the acute infection in cattle, while late abortions and birth defects in newborns can be associated with the infection of pregnant cows, ewes and goats (Hoffmann and others 2012, Van den Brom and others 2012). As of March 30, 2012, since the first identification of congenital forms of SBV virus infection in The Netherlands in December 2011, about 3000 confirmed outbreaks have been reported in eight European countries (Belgium, France, Germany, Italy, Luxembourg, The Netherlands, Spain, UK) (French National Surveillance Platform for Animal Health 2012). However, little is known about SBV virus infection, especially with regard to its clinical impact in the affected herds. SBV emergence is closely monitored in France. Farmers are urged to contact their veterinarian when encountering cases of ruminant neonates or fetuses stillborn, malformed or showing nervous disorders. A brain sample is collected on any newborn suspected of congenital SBV until a first confirmation of the infection is obtained for the herd. An SBV diagnostic test is performed in state diagnostic laboratories, using real-time quantitative reverse transcription PCR (RT-qPCR). The first cases of SBV virus infection were …

Demographics of the European Apicultural Industry

Over the last few years, many European and North American countries have reported a high rate of disorders (mortality, dwindling and disappearance) affecting honeybee colonies (Apis mellifera). Although beekeeping has become an increasingly professional activity in recent years, the beekeeping industry remains poorly documented in Europe. The European Union Reference Laboratory for Honeybee Health sent a detailed questionnaire to each Member State, in addition to Kosovo and Norway, to determine the demographics and state of their beekeeping industries. Based on data supplied by the National Reference Laboratory for honeybee diseases in each European country, a European database was created to describe the beekeeping industry including the number and types of beekeepers, operation size, industry production, and health (notifiable diseases, mortalities). The total number of beekeepers in Europe was estimated at 620 000. European honey production was evaluated at around 220 000 tons in 2010. The price of honey varied from 1.5 to 40 €/kg depending on the country and on the distribution network. The estimated colony winter mortality varied from 7 to 28% depending on the country and the origin of the data (institutional survey or beekeeping associations). This survey documents the high heterogeneity of the apicultural industry within the European Union. The high proportion of non-professional beekeepers and the small mean number of colonies per beekeeper were the only common characteristics at European level. The tremendous variation in European apicultural industries has implication for any comprehensive epidemiological or economic analysis of the industry. This variability needs to be taken into account for such analysis as well as for future policy development. The industry would be served if beekeeping registration was uniformly implemented across member states. Better information on the package bee and queen production would help in understanding the ability of the industry to replace lost honey bee stocks.

Why do farmers and veterinarians not report all bovine abortions, as requested by the clinical brucellosis surveillance system in France?

BackgroundSince 2005, France has been officially free of brucellosis, an infectious disease that causes abortion in cattle and can be transmitted from cattle to humans. Recent animal and human cases have drawn attention to the need to prevent infection of humans and animals from any primary outbreaks. In order to detect any new outbreaks as soon as possible, a clinical surveillance system requires farmers and veterinarians to report each abortion and to test the aborting cow for brucellosis. However, under-reporting limits the sensitivity of this system. Our objective was to identify the barriers and motivations influencing field actors in their decision to report or not to report bovine abortions. We used a qualitative approach with semi-structured interviews of 12 cattle farmers and their eight veterinarians.ResultsOur analysis showed that four main themes influence the decision-making process of farmers and veterinarians: 1) the perceived risk of brucellosis and other abortive diseases; 2) the definition of a suspected case of brucellosis and other abortive diseases adopted by field actors, which is less sensitive than the mandatory definition; 3) the cost-benefit analysis conducted by actors, taking into account regulatory and health aspects, economic and financial losses, technical and practical factors; 4) the level of cooperation within the socio-technical network. We discussed how early detection may be improved by revising the definition of abortion, extending the time frame for notification and generalising the differential diagnosis of the causes of abortion.ConclusionsIn contrast to quantitative approaches, qualitative studies can identify the factors (including unknown factors) influencing the decision-making process of field actors and reveal why they take those factors into consideration. Our qualitative study sheds light on the factors underlying the poor sensitivity of clinical brucellosis surveillance system for cattle in France, and suggests that early detection may be improved by considering actors’ perceptions. We believe our findings may provide further insight into ways of improving other clinical surveillance systems and thus reduce the risk of disease.

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.

Assessment of the utility of routinely collected cattle census and disposal data for syndromic surveillance

Census and disposal data provide a multipurpose source of information on cattle mortality. The retrospective analyses we conducted on the data gathered in the National Cattle Register produced relevant information for describing and modelling the cattle mortality baseline and evaluating the impact of the 2007-2008 Blue Tongue epidemic on the French cattle population. This work was conducted retrospectively but showed that monitoring cattle mortality near real time could help detecting unexpected events. We are thus currently working on a timely and automated system to monitor cadaver disposal requests received by rendering plants, thanks to a data interchange system recently implemented between the Ministry of Agriculture and the fallen stock companies. Besides technical and methodological challenges, using these data for surveillance purposes raises epidemiological questions that still need to be answered. The question remains notably as to whether an abnormal increased mortality is a sensitive and timely signal for detecting unexpected health events. It appears also very challenging to identify the most adequate surveillance scale (time, space and population) and the most adequate anomaly detection algorithms to apply when the characteristics of the signals to be detected (shape, amplitude, etc.) are not known a priori. In Human health, similar systems have not yet proven their ability to detect unexpected events earlier than classical surveillance systems currently in place, but they have already demonstrated their value for real time assessment of identified and potentially dangerous events. Combined with traditional surveillance systems, we think that monitoring routinely collected data could improve the surveillance of the animal population health. Even if not used for detection purposes, cattle mortality monitoring could be used to rapidly produce information on the impact and evolution of identified events, what would facilitate decision-making regarding management measures and improve the communication.

Using the National Cattle Register to estimate the excess mortality during an epidemic: application to an outbreak of Bluetongue serotype 8.

National Cattle Registers have been widely used to examine animal movements and their role in disease transmission, but less frequently for other epidemiological applications. Our study shows how routinely collected identification data can be used to evaluate the population impact of an epidemic in cattle and to derive an indirect estimate of the associated mortality. We adapted a method developed by Human health agencies, based on the modelling of historical mortality fluctuations, to analyze the evolution of mortality in a cattle population subjected to a Bluetongue serotype 8 (BT8) outbreak. Between 01/07/2007 and 01/07/2008, 21,017 cattle died in the considered population whereas 16,691 deaths were expected according to the model. 43% of the 4326 extra deaths were found in calves less than 7 days of age, but excess mortality was found in each age group. The temporal distribution of extra-deaths, described at a weekly scale, suggests that they were related to the BT8 epidemic. The presented method could be an appreciable tool for estimating the global burden of epidemics since it is based on data already routinely collected in each European Member State. This study was conducted retrospectively but considering the promptness of the notification system, the method could be used to monitor the evolution of epidemics in near-real time.

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.

Spread and impact of the Schmallenberg virus epidemic in France in 2012-2013

BackgroundThe Schmallenberg virus (SBV) emerged in Europe in 2011 and caused a widespread epidemic in ruminants.In France, SBV emergence was monitored through a national multi-stakeholder surveillance and investigation system. Based on the monitoring data collected from January 2012 to August 2013, we describe the spread of SBV in France during two seasons of dissemination (vector seasons 2011 and 2012) and we provide a large-scale assessment of the impact of this new disease in ruminants.ResultsSBV impact in infected herds was primarily due to the birth of stillborns or deformed foetuses and neonates. Congenital SBV morbidity level was on average moderate, although higher in sheep than in other ruminant species. On average, 8% of lambs, 3% of calves and 2% of kids born in SBV-infected herds showed typical congenital SBV deformities. In addition, in infected herds, farmers reported retrospectively a lower prolificacy during the vector season, suggesting a potential impact of acute SBV infection during mating and early stages of gestation.ConclusionsDue to the lack of available control and prevention measures, SBV spread quickly in the naive ruminant population. France continues to monitor for SBV, and updated information is made available online on a regular basis [http://www.plateforme-esa.fr/]. Outbreaks of congenital SBV are expected to occur sporadically from now on, but further epidemics may also occur if immunity at population level declines.

Surveillance systems evaluation: a systematic review of the existing approaches

BackgroundRegular and relevant evaluations of surveillance systems are essential to improve their performance and cost-effectiveness. With this in mind several organizations have developed evaluation approaches to facilitate the design and implementation of these evaluations.MethodsIn order to identify and to compare the advantages and limitations of these approaches, we implemented a systematic review using the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses).ResultsAfter applying exclusion criteria and identifying other additional documents via citations, 15 documents were retained. These were analysed to assess the field (public or animal health) and the type of surveillance systems targeted; the development process; the objectives; the evaluation process and its outputs; and the attributes covered. Most of the approaches identified were general and provided broad recommendations for evaluation. Several common steps in the evaluation process were identified: (i) defining the surveillance system under evaluation, (ii) designing the evaluation process, (iii) implementing the evaluation, and (iv) drawing conclusions and recommendations.ConclusionsA lack of information regarding the identification and selection of methods and tools to assess the evaluation attributes was highlighted; as well as a lack of consideration of economic attributes and sociological aspects.