Sylvain Falala

Identification of terms for detecting early signals of emerging infectious disease outbreaks on the web

Integrated approach to identify terms for monitoring disease emergence on the web.Terms are extracted automatically from disease outbreak web pages.Domain experts identify the terms relevant to characterise a disease emergence.Relevant terms are used as queries to mine the web. Timeliness and precision for detection of infectious animal disease outbreaks from the information published on the web is crucial for prevention against their spread. The work in this paper is part of the methodology for monitoring the web that we currently develop for the French epidemic intelligence team in animal health. We focus on the new and exotic infectious animal diseases that occur worldwide and that are of potential threat to the animal health in France.In order to detect relevant information on the web, we present an innovative approach that retrieves documents using queries based on terms automatically extracted from a corpus of relevant documents and validated with a consensus of domain experts (Delphi method). As a decision support tool to domain experts we introduce a new measure for ranking of extracted terms in order to highlight the more relevant terms. To categorise documents retrieved from the web we use Naive Bayes (NB) and Support Vector Machine (SVM) classifiers.We evaluated our approach on documents on African swine fever (ASF) outbreaks for the period from 2011 to 2014, retrieved from the Google search engine and the PubMed database. From 2400 terms extracted from two corpora of relevant ASF documents, 135 terms were relevant to characterise ASF emergence. The domain experts identified as highly specific to characterise ASF emergence the terms which describe mortality, fever and haemorrhagic clinical signs in Suidae.The new ranking measure correctly ranked the ASF relevant terms until position 161 and fairly until position 227, with areas under ROC curves (AUCs) of 0.802 and 0.709 respectively.Both classifiers were accurate to classify a set of 545 ASF documents (NB of 0.747 and SVM of 0.725) into appropriate categories of relevant (disease outbreak) and irrelevant (economic and general) documents.Our results show that relevant documents can serve as a source of terms to detect infectious animal disease emergence on the web.Our method is generic and can be used both in animal and public health domain.

Discrimination of two equine racing surfaces based on forelimb dynamic and hoof kinematic variables at the canter

The type and condition of sport surfaces affect performance and can also be a risk factor for injury. Combining the use a 3-dimensional dynamometric horseshoe (DHS), an accelerometer and high-speed cameras, variables reflecting hoof-ground interaction and maximal limb loading can be measured. The aim of the present study was to compare the effects of two racing surfaces, turf and all-weather waxed (AWW), on the forelimbs of five horses at the canter. Vertical hoof velocity before impact was higher on AWW. Maximal deceleration at impact (vertical impact shock) was not significantly different between the two surfaces, whereas the corresponding vertical force peak at impact measured by the DHS was higher on turf. Low frequency (0-200 Hz) vibration energy was also higher on turf; however high frequency (>400 Hz) vibration energy tended to be higher on AWW. The maximal longitudinal force during braking and the maximal vertical force at mid-stance were lower on AWW and their times of occurrence were delayed. AWW was also characterised by larger slip distances and sink distances, both during braking and at maximal sink. On a given surface, no systematic association was found between maximal vertical force at mid-stance and either sink distance or vertical impact shock. This study confirms the damping properties of AWW, which appear to be more efficient for low frequency events. Given the biomechanical changes induced by equestrian surfaces, combining dynamic and kinematic approaches is strongly recommended for a reliable assessment of hoof-ground interaction and maximal limb loading.

Comparison of superficial digital flexor tendon loading on asphalt and sand in horses at the walk and trot

The incidence of superficial digital flexor tendon (SDFT) injuries is one of the highest of all equine musculoskeletal conditions. Horses with SDFT injuries commonly show no improvement of lameness on soft ground, unlike those suffering from distal bone or joint lesions. The aim of this study was to compare the SDFT loading in five horses at the walk and trot on asphalt and sand using a non-invasive ultrasonic tendon force measurement device. Three horses were equipped with the ultrasonic device, whereas the other two horses were equipped with the ultrasonic device and a dynamometric horseshoe (DHS); the DHS was used to calibrate the measured values of tendon speed of sound (SOS) converted to tendon force, while a previously established ground reaction force pattern was used to calibrate SOS measurements for the other three horses. Although the horses tended to be slower on S, maximal tendon force was higher on sand than on asphalt at the trot (+6%); there was no significant difference between the two surfaces at the walk. The duration of tendon loading was longer on S (+5%) and the area under the tendon force-time curve was larger on S (+10%) at both walk and trot. SDFT loading is significantly affected by the ground surface and the observed increase in SDFT loading on sand compared with asphalt is consistent with clinical observations in horses with SDFT injuries.

Comparative kinematic analysis of the leading and trailing forelimbs of horses cantering on a turf and a synthetic surface

REASONS FOR PERFORMING STUDY The relationship between track surface properties and limb kinematics is poorly understood. Hoof orientation within the track surface has never been quantified under training conditions. Previously described kinematic and dynamic differences between leading and trailing forelimbs at the canter poorly correlate with epidemiological data regarding injuries. OBJECTIVES To compare joint kinematics and hoof orientation in the leading and trailing forelimbs of horses cantering on turf and on a synthetic surface. STUDY DESIGN Noninvasive experimental study. METHODS The right forelimb of 5 horses was equipped with markers facing the main joints while markers and a dynamometric horseshoe were placed on the hoof. The horses were filmed with 2 high-speed cameras (1000 Hz) while cantering (30 km/h). Recordings were repeated at each lead and alternated on turf and on a synthetic surface. Joint angles and angles of the hoof and limb to the track were measured from the 2-dimensional coordinates of the markers. RESULTS Elbow, carpus and fetlock were more maximally flexed during swing and had a larger range of motion throughout the stride in the leading forelimb. Maximal carpal extension during stance was also larger on this limb, which had a more toe-up orientation. Comparing surfaces, the limb was more oblique at landing, the range of motion of the hoof into the surface was larger, most kinematic events were delayed and fetlock and carpus extension velocities were smaller on the synthetic surface. CONCLUSIONS The differences between limbs were more prominent than those between surfaces and the more toe-up orientation on the hoof of the leading forelimb suggests a different loading of that limbs joints and tendons. Differences between limbs may be important in the interpretation of lead changes in lame horses. While the synthetic surface appears to be less strenuous for the joints in the forelimbs, it was associated with changes in timing of the kinematic events of the stride.

Identification of Associations between Clinical Signs and Hosts to Monitor the Web for Detection of Animal Disease Outbreaks

In a context of intensification of international trade and travels, the transboundary spread of emerging human or animal pathogens represents a growing concern. One of the missions of the national veterinary services is to implement international epidemiological intelligence for a timely and accurate detection of emerging animal infectious diseases (EAID) worldwide, and take early actions to prevent their introduction on the national territory. For this purpose, an efficient use of the information published on the web is essential. The authors present a comprehensive method for identification of relevant associations between terms describing clinical signs and hosts to build queries to monitor the web for early detection of EAID. Using text and web mining approaches, they present statistical measures for automatic selection of relevant associations between terms. In addition, expert elicitation is used to highlight the most relevant terms and associations among those automatically selected. The authors assessed the performance of the combination of the automatic approach and expert elicitation to monitor the web for a list of selected animal pathogens.

Web monitoring of emerging animal infectious diseases integrated in the French Animal Health Epidemic Intelligence System

Since 2013, the French Animal Health Epidemic Intelligence System (in French: Veille Sanitaire Internationale, VSI) has been monitoring signals of the emergence of new and exotic animal infectious diseases worldwide. Once detected, the VSI team verifies the signals and issues early warning reports to French animal health authorities when potential threats to France are detected. To improve detection of signals from online news sources, we designed the Platform for Automated extraction of Disease Information from the web (PADI-web). PADI-web automatically collects, processes and extracts English-language epidemiological information from Google News. The core component of PADI-web is a combined information extraction (IE) method founded on rule-based systems and data mining techniques. The IE approach allows extraction of key information on diseases, locations, dates, hosts and the number of cases mentioned in the news. We evaluated the combined method for IE on a dataset of 352 disease-related news reports mentioning the diseases involved, locations, dates, hosts and the number of cases. The combined method for IE accurately identified (F-score) 95% of the diseases and hosts, respectively, 85% of the number of cases, 83% of dates and 80% of locations from the disease-related news. We assessed the sensitivity of PADI-web to detect primary outbreaks of four emerging animal infectious diseases notifiable to the World Organisation for Animal Health (OIE). From January to June 2016, PADI-web detected signals for 64% of all primary outbreaks of African swine fever, 53% of avian influenza, 25% of bluetongue and 19% of foot-and-mouth disease. PADI-web timely detected primary outbreaks of avian influenza and foot-and-mouth disease in Asia, i.e. they were detected 8 and 3 days before immediate notification to OIE, respectively.

LE PROJET SEQUISOL: ÉVALUATION BIOMÉCANIQUE DE L'EFFET DES SOLS ÉQUESTRES SUR L'APPAREIL LOCOMOTEUR DU CHEVAL

The quality of ground surfaces conditions equine locomotion and can be a risk factor for osteoarticular and tendinous lesions. A novel protocol of biomechanical measurements has been developed to characterize the effects of ground surfaces on the locomotor system and locomotion of harnessed trotter horses under training conditions. This protocol is based on the simultaneous use of a 3D dynamometric horseshoe, a 3D accelerometer, a superficial digital flexor (SDF) tendon force ultrasonic sensor, inertial measurement units, and a high-speed camera. Three French trotters were used to compare two tracks at the Grosbois training centre (crushed sand and all-weather waxed track) ; biomechanical measurements were performed at a standardized speed (9.7 m/s, i.e. 35 km/h). The all-weather waxed track appeared as the most damping (shock absorbing), i.e. lesser impact deceleration and braking force and lesser maximal loading rate of the SDF tendon. However, the horse’s locomotor comfort (determined by the stride length) did not seem to be greater. The preliminary results of the tests performed since October 2006 as part of the Sequisol project (10 tracks tested on 5 different sites) confirm superior shock-absorbing properties as well as a “slower” characteristic during the braking phase for the all-weather waxed tracks, and generally speaking, the strong influence of maintenance conditions of the surfaces on the biomechanical results.