Evaluation of a hierarchical ascendant clustering process implemented in a veterinary syndromic surveillance system.

Syndromic surveillance is considered as one of the surveillance components for early warning of health-related events, as it allows detection of aberrations in health indicators before laboratory confirmation. "MoSS-Emergences 2" (MoSS-E2), a tool for veterinary syndromic surveillance, aggregates groups of similar clinical observations by hierarchical ascendant classification (HAC). In the present study, this HAC clustering process was evaluated using a reference set of data that, for the purpose of this evaluation, was a priori divided and defined as Bluetongue (BTV) positive cases (PC) on the one hand and BTV negative cases (NC) on the other hand.

Reproducibility of local environmental factors for the abundance of questing Ixodes ricinus nymphs on pastures.

In ecology and epidemiology, exploratory field studies based on multivariate statistical models commonly are used to identify factors that are associated with a phenomenon. The challenge is to evaluate whether these factors are indeed correlated to the phenomenon or if the statistical significance results from fortuitous association or type 1 statistical error (probability of rejecting a null hypothesis when it is true). This is particularly the case when the phenomenon is linked to environmental factors that usually are more or less correlated to each other and when the phenomenon is itself highly variable.

Ecological factors characterizing the prevalence of bacterial tick-borne pathogens in Ixodes ricinus ticks in pastures and woodlands.

Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp.

A nation-wide epidemiological study of acute bovine respiratory disease in France.

Acute bovine respiratory disease (ABRD) is a respiratory syndrome caused by various infectious agents, and represents a major economic and health problem in cattle herds worldwide. The aim of the study was to present how we can describe the epidemiological characteristics of ABRD in France, including risk factor analysis and spatio-temporal pattern investigation. The data were collected by specialized surveyors during the 2001 animal survey conducted by the French Ministry for Agriculture and Fisheries, from a representative sample of cattle herds.

Mammal and bird species distribution at the woodland-pasture interface in relation to the circulation of ticks and pathogens.

The tick vector Ixodes ricinus can be found in pastures in landscapes where pasture and woodland intermix, such as in the bocage. To identify which mammal or bird species could potentially transport ticks between woodland and pasture, we did a species inventory on four French bocage sites in 2005. Fifty-eight species were observed, 21 of which were found in three different habitats: the middle of the pasture, the hedgerow ecotone, and the woodland.

The relationships between Ixodes ricinus and small mammal species at the woodland-pasture interface.

Ixodes ricinus, as vector, and small mammals, as reservoirs, are implicated in pathogen transmission between wild fauna, domestic animals and humans at the woodland-pasture interface. The ecological relationship between ticks and small mammals was monitored in 2005 on four bocage (enclosed pastureland) sites in central France, where questing ticks were collected by dragging and small mammals were trapped. Questing I.

A spatial hazard model for cluster detection on continuous indicators of disease: application to somatic cell score.

Methods for spatial cluster detection dealing with diseases quantified by continuous variables are few, whereas several diseases are better approached by continuous indicators. For example, subclinical mastitis of the dairy cow is evaluated using a continuous marker of udder inflammation, the somatic cell score (SCS). Consequently, this study proposed to analyze spatialized risk and cluster components of herd SCS through a new method based on a spatial hazard model.

Prevalence of Anaplasma phagocytophilum, Rickettsia sp. and Borrelia burgdorferi sensu lato DNA in questing Ixodes ricinus ticks from France.

A total of 4701 Ixodes ricinus, collected during the summer of 2003, were analyzed for three pathogens. DNA was detected from the three pathogens. Co-detection of more than one pathogen was observed.

Detecting emerging diseases in farm animals through clinical observations.

Predicting emerging diseases is among the most difficult challenges facing researchers and health managers. We present available approaches and tools to detect emerging diseases in animals based on clinical observations of farm animals by veterinarians. Three information systems are described and discussed: Veterinary Practitioner Aided Disease Surveillance in New Zealand, the Rapid Syndrome Validation Project-Animal in the United States, and "émergences" in France.

Broad-range PCR-TTGE for the first-line detection of bacterial pathogen DNA in ticks.

Ticks are known or suspected vectors for a wide range of bacterial pathogens. One of the first steps for tick-borne risk assessment is the detection of these pathogens in their vectors. In the present study, a broad-range PCR amplification of the eubacterial gene encoding the 16S rRNA gene combined with Temporal Temperature Gradient gel Electrophoresis (TTGE) was evaluated as a method allowing the one-step detection of bacterial pathogen DNA in ticks.

Statistical modelling for clinical mastitis in the dairy cow: problems and solutions.

Modelling case occurrence and risk factors for clinical mastitis, as a key multifactorial disease in the dairy cow, requires statistical models. The type of model used depends on the choice of perception or the study level: herd, lactation, animal, udder and quarter. The validity of the tests that are performed through these models is especially ensured when hypotheses of independence between statistical units are respected, and when the model adjustments do not involve overdispersion faced with the observed data.