[Show abstract][Hide abstract] ABSTRACT: In early 2001, Mycobacterium bovis infection was confirmed in red deer (RD) (Cervus elaphus) shot in Normandy region, France. An epidemiological survey conducted during the following hunting season in two connected forests confirmed the occurrence of the disease in both free-ranging RD and wild boar (WB) (Sus scrofa). This was the first detected bovine tuberculosis outbreak in wildlife in France. We present a simple deterministic age-structured model of the within- and between-species M. bovis transmission in RD and WB populations that distinguishes direct transmission (horizontal and pseudo-vertical) and indirect transmission through contaminated offal left behind by hunters. Results issued from the epidemiological surveys conducted in Normandy forests were used to estimate transmission parameters. Because data for RD and WB populations were not available, population sizes at demographic equilibrium were estimated and used to run the model. We qualitatively tested different control measure scenarios with our model, considering different mortality rates and offal harvesting, to determine which ones affect the success of infection control. The most realistic control scenario would combine the total depopulation of RD and good compliance with offal harvesting, because the model suggests that infected offal left by hunters represents the main transmission source of M. bovis in the field.
Zoonoses and Public Health 09/2012; 59(s2). · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Risk assessment can be either quantitative, i.e. providing a numeric estimate of the probability of risk and the magnitude of the consequences, or qualitative, using a descriptive approach. The French Agency for Food, Environmental and Occupational Health and Safety (ANSES), formerly the French Food Safety Agency (AFSSA), bases its assessments on the opinions of scientific panels, such as the ANSES Animal Health Scientific Panel (AH-SP). Owing to the lack of relevant data and the very short period of time usually allowed to assess animal health risks on particular topics, this panel has been using a qualitative risk method for evaluating animal health risks or crises for the past few years. Some experts have drawn attention to the limitations of this method, such as the need to extend the range of adjectives used for the lower probabilities and to develop a way to assess consequences. The aim of this paper is to describe the improved method now established by the AH-SP, taking into account the limitations of the first version. The authors describe a new set of levels for probabilities, as well as the items considered when addressing either animal or human health consequences.
Revue scientifique et technique (International Office of Epizootics) 12/2011; 30(3):673-81. · 0.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cet ouvrage est le fruit d'une collaboration entre des spécialistes de la surveillance épidémiologique. La première partie est un véritable guide pratique à l'attention de tous les acteurs des réseaux de surveillance épidémiologique et plus particulièrement des animateurs et acteurs impliqués dans leur conception, leur organisation et leur fonctionnement. La deuxième partie offre des exemples concrets qui soulignent, malgré la diversité des sujets traités, une démarche méthodologique identique.
Edited by QUAE & AEEMA, 05/2011; QUAE., ISBN: 978-2-7592-0909-5
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to develop a standardized tool for the assessment of surveillance systems on zoonoses and animal diseases. We reviewed three existing methods and combined them to develop a semi-quantitative assessment tool associating their strengths and providing a standardized way to display multilevel results. We developed a set of 78 assessment criteria divided into ten sections, representing the functional parts of a surveillance system. Each criterion was given a score according to the prescription of a scoring guide. Three graphical assessment outputs were generated using a specific combination of the scores. Output 1 is a general overview through a series of pie charts synthesizing the scores of each section. Output 2 is a histogram representing the quality of eight critical control points. Output 3 is a radar chart representing the level reached by ten system attributes. This tool was applied on five surveillance networks.
Epidemiology and Infection 03/2011; 139(10):1486-96. · 2.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Global changes, including an increase in trade and global warming, which act on the environment, are likely to impact on the evolution of pathogens and hence of diseases. To anticipate the risks created by this new situation, a French group of experts has developed a method for prioritising animal health risks. This is a two-phase method: the first step is to identify the diseases whose incidence or geographical distribution could be affected by the changes taking place, and the second step is to evaluate the risk of each of these diseases. As a result of this process, six priority diseases were selected: bluetongue, Rift Valley fever, West Nile fever, visceral leishmaniasis, leptospirosis and African horse sickness. The main recommendations were: to develop epidemiological surveillance, to increase knowledge of epidemiological cycles, to develop research into these diseases and to pool cross-border efforts to control them.
Revue scientifique et technique (International Office of Epizootics) 09/2008; 27(2):529-50. · 0.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The data obtained from a survey of Mycobacterium bovis infection in wild red deer (Cervus elaphus) and wild boar (Sus scrofa) conducted in France in the 2005/06 hunting season were used to describe and quantify the pathological findings in the two species. The red deer had caseous abscessed lesions in their organs and lymph nodes, whereas in the wild boar the lesions were predominantly caseocalcareous and occurred mainly in the lymph nodes. The severity of the gross tuberculosis-like lesions was estimated on the basis of a numerical score. The significant difference between the distribution of the scores in the two species indicated that the disease was more serious in the red deer than in the wild boar. Unlike the red deer, the wild boar did not show a generalised pattern of disease. Among the lymph nodes examined systematically, gross lesions were most frequently observed in the mesenteric lymph nodes in the red deer and in the retropharyngeal lymph nodes in the wild boar. In both species, the presence of gross lesions showed the closest agreement with the isolation of M bovis from the same lymph nodes. The different patterns of the lesions of tuberculosis in the two species suggest that red deer might play an important role in the intraspecies and interspecies dissemination of the infection, whereas in wild boar the spread of the infection would be more likely to be restricted to other wild boar.
The Veterinary record 08/2008; 163(2):43-7. · 1.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In early 2001, tuberculosis-like lesions were detected in three hunter-killed red deer (Cervus elaphus) in the Brotonne Forest (Normandy, France), and Mycobacterium bovis was isolated. In subsequent hunting seasons, two surveys were conducted in the area. In the first survey (2001-02 hunting season), nine (13%) of 72 red deer sampled were positive for M. bovis. In the 2005-06 hunting season, the prevalence of M. bovis infection increased to 24% (chi2=3.85, df=1, P=0.05; 33 positive among 138 sampled). The prevalence remained stable in juveniles, but it increased significantly in adults: from 13% in 2001-02 to 32% in 2005-06 (chi2=5.13, df=1, P=0.02). Wild boar (Sus scrofa) were heavily infected in both surveys. One roe deer (Capreolus capreolus) and one red fox (Vulpes vulpes) also tested positive in the second survey. Mycobacterium bovis was not isolated from Eurasian badgers (Meles meles). Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat analysis demonstrated that all M. bovis strains isolated from wildlife were of the same genotype. Thus, the wildlife outbreak involved only a single strain, and this strain was the same as that circulating in nearby cattle herds since 1995. Sensitivity, specificity, and predictive values of the presence of macroscopic lesions as a diagnostic criterion were evaluated from the data obtained from red deer. Necropsy seems to be satisfactory as a routine tool to monitor the disease in wild red deer populations in which bovine tuberculosis has become established.
Journal of wildlife diseases 02/2008; 44(1):99-108. · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Risk analysis can be performed following either a quantitative or a qualitative approach. Both methodologies are linked to
the same theoretical rules. Once the potential hazard has been identified, the qualitative risk assessment is carried out
by combining the probabilities of occurrences of the events (emission and exposition) in the presence of a hazard, and its
consequences. The probability of an event can be evaluated by combining the probabilities of the different parameters.
Within the frame of global expertise, the necessity of realizing collegial risk evaluations, sometimes when only few data
are available and within a short amount of time, leads us to work on a standardised method for a qualitative approach.
The process of global qualitative risk appreciation is completed by adding support to the rationalisation of the estimation
step. It has been proposed that each parameter be evaluated with the help of all available information and that an evaluation
of the probability of occurrence of each of these can be realized individually to yield a given level of probability (null,
negligible, low, moderate, high) or an interval between two levels (for example: ‘negligible to low’).
The combination of probabilities and of intervals was carried out using a table that was tested and evaluated through the
following risk assessment: qualitative risk evaluations of the transmission of Q fever to humans in France.
Both the advantages and the limitation of this approach are also presented.
[Show abstract][Hide abstract] ABSTRACT: The appearance of foot and mouth disease (FMD) in the United Kingdom in late February 2001 took European veterinary services by surprise. Differences in the types of measures taken by European countries, and in the speed with which they were implemented, partly explain the different animal health situations observed. France, as a major importer of British sheep, is an interesting country to study. The measures taken there are described in detail, as is the history of the two cases registered on 13 and 23 March 2001. The crisis management procedure is also detailed. The majority of the decisions taken and protocols followed are part of the national intervention plan for FMD. However, experience has shown that it is also important to remain pragmatic and to be able to adapt to new developments during the implementation of the plan. While pre-emptive killing may indeed have reduced the number of outbreaks in France, the social impact of such measures also needs to be taken into account in the development of animal health policy.
Revue scientifique et technique (International Office of Epizootics) 01/2003; 21(3):731-7, 723-30. · 0.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The spatial spread of foot-and-mouth disease (FMD) is influenced by several sources of spatial heterogeneity: heterogeneity of the exposure to the virus, heterogeneity of the animal density and heterogeneity of the networks formed by the contacts between farms. A discrete space model assuming that farms can be reduced to points is proposed to handle these different factors. The farm-to-farm process of transmission of the infection is studied using point-pattern methodology. Farm management, commercial exchanges, possible airborne transmission, etc. cannot be explicitly taken into account because of lack of data. These latter factors are introduced via surrogate variables such as herd size and distance between farms. The model is built on the calculation of an infectious potential for each farm. This method has been applied to the study of the 1967-1968 FMD epidemic in UK and allowed us to evaluate the spatial variation of the probability of infection during this epidemic. Maximum likelihood estimation has been conducted conditional on the absence of data concerning the farms which were not infected during the epidemic. Model parameters have then been tested using an approximated conditional-likelihood ratio test. In this case study, results and validation are limited by the lack of data, but this model can easily be extended to include other information such as the effect of wind direction and velocity on airborne spread of the virus or the complex interactions between the locations of farms and the herd size. It can also be applied to other diseases where point approximation is convenient. In the context of an increase of animal density in some areas, the model explicitly incorporates the density and known epidemiological characteristics (e.g. incubation period) in the calculation of the probability of FMD infection. Control measures such as vaccination or slaughter can be simply introduced, respectively, as a reduction of the susceptible population or as a reduction of the source of infection.
Preventive Veterinary Medicine 12/2002; 56(1):33-49. · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The study of the available information, notably after the epizootic of foot-and-mouth disease (FMD) which raged in Western Europe in 2001, shows that, in the current conditions of the international sanitary rules relative to this disease, in a FMD-free country of Western Europe accidentally infected, ring vaccination is a solution which, with regard to preventive slaughter, contains more inconveniences (notably economic) than advantages. The appeal to ring vaccination would be interesting only as far as the international sanitary rules would be modified by taking into account the results expected from the coordinated use of highly purified vaccines and differential research kits (vaccine-linked versus infection-linked antibodies). Propositions are this way made.
[Show abstract][Hide abstract] ABSTRACT: Although known for many years, foot-and-mouth disease is still able to represent a real threat to many farming economies in the world. The recent 2001 Western European epizootics linked to O PanAsia virus strain can illustrate the fact that many questions are still unanswered in the field of foot-and-mouth epidemiology. It also demonstrates that the increase in international trade, including livestock, animal products and animal food, means an increase in the probability of transmitting, through the same way, some animal diseases, foot-and-mouth included. In our economies, a rapid identification of the virus and a fast elimination of infected, contaminated and even some contact animals are still the key factors to react in front of such a disease.
[Show abstract][Hide abstract] ABSTRACT: A qualitative risk assessment was performed to evaluate the risk of introducing foot and mouth disease (FMD) virus into Russia and the rest of Europe from the countries of Transcaucasia (Armenia, Azerbaijan and Georgia). The assessment was based on data collected during a three-week mission to these countries by the Food and Agriculture Organization, the European Union and the Office International des Epizooties in March 1999. Due to the strong involvement of the local veterinary services, much information was obtained. Although the data were not sufficient to allow a quantitative risk assessment to be performed, the investigation served as a useful initial approach, prior to undertaking a quantitative risk assessment. The risk of FMD virus infection is a function of two elements, namely: the probability of the hazard (virus infection) occurring, and the magnitude of the consequences. The probability of the hazard occurring is the product of the probability of entry of the virus and the probability of exposure to the virus. These elements were assessed using the following parameters: prevalence of infection; volume of trade; capacity of the virus to survive; and potential for infection. The magnitude of the consequences is derived from the probability of transmission and spread. Combining these parameters, the probability of occurrence of the hazard was rated as 'moderate'. Economic consequences of potential transmission and spread of FMD, in the local context, were rated as 'negligible'. As a result, the overall risk of introducing FMD virus into Russia and the rest of Europe from Trancaucasia was rated as 'low' at the time of evaluation. The method and results are presented to serve as a basis for further discussion.
Revue scientifique et technique (International Office of Epizootics) 01/2002; 20(3):723-30. · 0.69 Impact Factor