Defining an emerging disease.

Defining an emerging disease is not straightforward, as there are several different types of disease emergence. For example, there can be a 'real' emergence of a brand new disease, such as the emergence of bovine spongiform encephalopathy in the 1980s, or a geographic emergence in an area not previously affected, such as the emergence of bluetongue in northern Europe in 2006. In addition, disease can emerge in species formerly not considered affected, e.g. the emergence of bovine tuberculosis in wildlife species since 2000 in France. There can also be an unexpected increase of disease incidence in a known area and a known species, or there may simply be an increase in our knowledge or awareness of a particular disease. What all these emerging diseases have in common is that human activity frequently has a role to play in their emergence. For example, bovine spongiform encephalopathy very probably emerged as a result of changes in the manufacturing of meat-and-bone meal, bluetongue was able to spread to cooler climes as a result of uncontrolled trade in animals, and a relaxation of screening and surveillance for bovine tuberculosis enabled the disease to re-emerge in areas that had been able to drastically reduce the number of cases. Globalisation and population growth will continue to affect the epidemiology of diseases in years to come and ecosystems will continue to evolve. Furthermore, new technologies such as metagenomics and high-throughput sequencing are identifying new microorganisms all the time. Change is the one constant, and diseases will continue to emerge, and we must consider the causes and different types of emergence as we deal with these diseases in the future.

The second eradication: rinderpest.

The eradication of rinderpest virus was less celebrated than the eradication of smallpox virus. However, this is only the second campaign to eradicate a virus worldwide which is successful. This gives the opportunity to recall how important rinderpest had been these past centuries for farmers and for public health.

Risks of emerging infectious diseases: evolving threats in a changing area, the mediterranean basin.

The Mediterranean basin is a biodiversity hotspot; it has historically had a large human presence that has shaped ecosystems for millennia. As the cradle of many civilizations, the area was one of the main theatres for transitions that punctuated both human and pathogen histories, which are intimately linked. Today we are living through another great historical transition summarized in the expression 'global changes'. In this context, we are witnessing a rise in the emergence of pathogens widely associated with aforementioned global changes. The Mediterranean basin might be especially vulnerable to this phenomenon due to the acute consequences global changes will have in this key intercontinental interface region. In addition, Arab revolutions and European economic crisis are creating both sanitary issues and presenting new opportunities to improve infectious disease control and prevention in the region. The aim of this review is to identify the impacts that ongoing changes might have on the risk of infectious disease emergence in the Mediterranean basin. We focussed on three key domains undergoing transformations: (i) resources, namely safe drinking water and animal products, (ii) socio-economic factors including health inequalities within countries and poor sanitary conditions linked to ongoing conflicts and (iii) movements of people and goods that are reshaped by current changes and are intimately linked to the risk of disease proliferation. Building on recent examples, we try to identify upcoming challenges and discuss ways to meet them in the light of existing international human and veterinary health guidelines and their possible improvements.

Modelling transmission of bovine tuberculosis in red deer and wild boar in Normandy, France.

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.

OASIS: an assessment tool of epidemiological surveillance systems in animal health and food safety.

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.

A qualitative risk assessment methodology for scientific expert panels.

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.

Invasive mammals.

Every region of the world is concerned by potential mammal invasions, as humans are already present on all the world's land masses. All these invasions are a result of species introductions by humans for one reason or another. The authors briefly review the known movements and observed consequences of mammal-related invasions. They take examples from all five continents, as well as from a few island systems. The ancient introduction of game species, and later of domestic species, has been followed more recently by movements of commercial species. We are now seeing the emergence of what are known as entertainment species. In a number of cases, such introductions have led to the establishment of new epidemiological cycles that previously might never have been thought possible. According to current indicators, this phenomenon is not on the wane.

Invasive reptiles and amphibians.

Although they are frequently lumped together, reptiles and amphibians belong to two very different zoological groups. Nevertheless, one fact is clear: while numerous reptile and amphibian species on Earth are in decline, others have taken advantage of trade or human movements to become established in new lands, adopting different, and sometimes unusual, strategies. The authors have taken a few examples from these two zoological groups that illustrate the majority of cases. A brief analysis of the causes and effects of their introductions into new areas reveals connections with economic interests, trade in companion animals, medical research and public health.

Why own an exotic pet?

Even though people have owned a wide variety of companion animals since times of old, the modern craze for increasingly exotic and little-known species raises a number of questions, including some of an ethical nature. While trade in exotic animals is certainly profitable for these who practise it, it poses great risks of varying types: ecological risks, threats to biodiversity conservation and health risks. Several introduced animal populations have gone on to establish a line in their new host country. We are just starting to measure the adverse impact this has had, in some cases on a very large scale. The veterinary profession doubtless has a major role to play in endeavouring to reform this trade in living creatures that unfortunately results in many losses.

Invasive species. Part 1: general aspects and biodiversity. Part 2: concrete examples.

The problem of invasive species is of interest to researchers in a variety of different fields, including biology, epidemiology, agriculture, public health and even human sciences. It is an issue that affects all regions of the world to a greater or lesser extent. It can also have detrimental effects on animal health and biodiversity. For example, the International Union for the Conservation of Nature (lUCN) reported that 625 (51%) of known endangered species are threatened because of invasive (alien) species.

Defining an invasive species.

The definition of an invasive species will depend on the viewpoint of the observer, who in some cases may be responsible for introducing the species. History has taught us that humans are the species that has invaded the largest surface area of the planet. So, before going on to propose a few definitions, this article describes three different examples or types of example in which domestic animal species, wild animal species and microorganisms (for biological pest control) have been transported intentionally. By doing so, this paper uses a variety of situations to support the definitions. A contemporary argument would counter a strictly biogeographical definition with a more ecological definition. The two are probably complementary. In any case, these definitions should remain practical. The consequences of species movements vary. However, their health impacts should not be underestimated.

Geographical distribution of domestic animals: a historical perspective.

Our understanding of the history of animal domestication has been built on regular input from archaeozoology. This fast-expanding discipline uses increasingly sophisticated and specialised tools to enhance our knowledge of phenomena dating back, for the oldest species, to the Neolithic Revolution. This article takes three examples, those of the domestic dog, domestic goat and European rabbit, to illustrate the history of three different domestication processes using the contemporary means available. In each of the three cases, the authors define the location of original domestication, analyse the principal routes of species movements following domestication, discuss the possible reasons for domestication and suggest a few likely epidemiological impacts.

Global change: impact, management, risk approach and health measures--the case of Europe.

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.

Patterns of lesions of bovine tuberculosis in wild red deer and wild boar.

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.

[Survey of foot and mouth disease in France]. / Le système de surveillance de la fièvre aphteuse en France.

The Foot and Mouth disease is considered a relatively mild disease in susceptible animals but it has a considerable economical impact in France and worldwide due to the huge economical losses that it generates. A system for the prevention of the disease was developed thirty years ago and has since been continuously improved. The current system for the prevention of FMD is based on training and information of all those involved in the surveillance of susceptible animals, over all the national territory, and on the control of imported animals and animal products. This system, developed in close collaboration with the European Commission and the other EU member states, allows control measures to be implemented almost instantaneously, if a case is suspected to avoid spreading of the disease.