CIRAD will be participating in the International Conference on Animal Health Surveillance – ICAHS in Lyons from 17 to 20 May, which will be bringing together the whole range of stakeholders , scientists and politicians involved in epidemiological surveillance for animal health.

As researchers put it: “emerging animal diseases are continuing to progress, including z oonoses, which pose a serious threat to human communities in both North and South ”. Some of these diseases, which are being addressed by a number of CIRAD research projects, so recurrently affect animals and geographical areas that they are now seen as emblematic.

Surveillance

CIRAD has a long tradition of research on preventing the health risks threatening countries in the South. It identifies and assesses the risks linked to wildlife and domestic animals, through surveillance networks. Using models and scenarios, it tests integrated prevention, management and intervention tools for the surveillance, prevention and control of the causes and consequences of these risks.

To this end, it favours:
- a “risk analysis ” approach, looking at the epidemiological and socioeconomic consequences of a disease for animal and human populations, systems and supply chains, including prevention and management aspects. For instance, the constraints on or incentives for farmers as regards declaring diseases in their animals to the health authorities (eg avian influenza in Vietnam).

- a “health ecology ” approach, focusing on the functioning of systems or communities including people and wild or domestic animals, within which pathogens are circulating.

At the request of the FAO or the OIE, the AGIRs team also regularly organizes training courses for staff members from veterinary services in various world regions. These courses are notably intended to allow people involved in epidemiological surveillance networks to supply tools to improve the gathering, management and processing of data from epidemiological surveillance operations. Tools have been specially developed for such courses (see Ranema and Ranema-FLU on the CIRAD e-learning platform).

A few examples of applications

Understanding the epidemiology of a disease better so as to propose appropriate surveillance and control methods

African swine fever (ASF) affects domestic and wild pigs, wild boars in Europe and Africa, warthogs, and river hogs. It is passed on through contact between sick and healthy animals. The threat of introduction is high for Europe (Corsica and Sardinia), and also for Asia.

The results obtained by CIRAD ( identification of the ecological, epidemiological and socioeconomic factors that determine the disease, assessment of the risks of its introduction and spread, perception of the disease by farmers), which has been studying ASF for several years, have enabled a clearer definition of surveillance and control strategies, targeting at-risk populations and ecosystems.

Assessing the risks of the introduction or spread of a disease

Rift Valley fever (RVF) is a zoonosis (disease that can be passed from animals to man) that affects many species (ovines, sheep, camels and goats). It is transmitted between animals through mosquito bites. RVF affects Africa, and also Saudi Arabia and Yemen. It is also a threat to Eurasia.

CIRAD is working on RVF transmission mechanisms in several countries affected by the disease (Madagascar, southern Africa), and also in as-yet disease-free countries with a view to assessing the risks of introduction (for instance in Thailand). Thanks to the networks it has set up, it is in a position to assess the risks of disease spread, and above all to make risk management recommendations aimed at preventing its spread.

Assessing the risks of the emergence of a new disease so as to prevent it more effectively

Bats are the second largest order of mammals, with more than 930 known species. By virtue of their diversity and ability to fly (unique in mammals), they play a major role in maintaining and transmitting infection within ecosystems. They are therefore vitally important to the emergence of diseases in animals and man (rabies, encephalitis, Ebola and Marburg haemorrhagic fevers, etc).

CIRAD, in partnership with the CIRMF (Centre international de recherches médicales de Franceville) and the IRD, is currently working in Gabon on cave bats and their role as reservoirs of pathogens that could be a threat to man. The aim of the research project is to determine the sanitary risks associated with the presence of Chiroptera for human populations living near caves with huge numbers of bats: what are the mechanisms by which pathogens are maintained and transmitted among cave bat communities, and what determines the emergence of a disease and/or the appearance of an epidemic? In Southeast Asia, following successive epidemics linked to the Nipah virus in man and in domestic pigs, CIRAD began working with the Institut Pasteur in Cambodia and Mahidol University in Thailand on a Nipah-bat model designed to estimate the risks of and factors in the emergence of the disease in Southeast Asia.

Developing methods enabling better assessment of avian influenza surveillance systems

Avian influenza is persisting in several countries, and the FAO considers that the elimination in poultry of the highly pathogenic H5N1 avian influenza virus in the six countries in which it remains endemic will take at least ten years. The countries concerned are primarily in Asia, along with Egypt as regards Africa. The influenza viruses affecting birds and those affecting domestic pigs should be placed under close surveillance so as also to assess the risks of transmission to man.

In Southeast Asia, CIRAD is leading the REVASIA programme, aimed at developing innovative methods for assessing the epidemiological and socioeconomic performance of surveillance systems. Similar work is also planned in Egypt. These approaches fit in with the One Health Initiative, which is studying the interface between animals and man, in particular by analyzing the links between animal health and public health systems. Three presentations of the programme are scheduled for the ICAHS (see below).

CIRAD at the ICAHS

Researchers from the Animal and Integrated Risk Management (AGIRs) Research Unit will be showing posters and giving five oral presentations at the ICAHS:

- Dimensionnement et comparaison des différents systèmes de surveillance de la fièvre du Nil occidental dans un contexte européen en évolution [Sizing and comparison of various West Nile virus surveillance systems in a changing European context] (Véronique Chevalier)

- Systèmes de surveillance formels et informels : comment établir des passerelles ? [Formal and informal surveillance systems: how can we build bridges?] (Stéphanie Desvaux)

- Évaluation des systèmes de surveillance épidémiologique en santé animale : nécessité d’adapter les outils au contexte des pays en développement, résultats d’un colloque régional en Asie du sud-est [Assessing epidemiological surveillance systems for animal health: need to adapt tools to the situation in developing countries, results of a regional symposium in Southeast Asia] (Marisa Peyre)

- Évaluation du système de surveillance de la grippe aviaire H5N1 dans les élevages de volailles en basse-cour et en plein air en Thaïlande [Assessment of the H5N1 avian influenza surveillance system in open-air poultry rearing systems in Thailand] (Flavie Goutard)

- La méthode de capture-recapture comme outil d’évaluation de la surveillance des maladies animales : l’exemple de la fièvre aphteuse au Cambodge [The capture-recapture method as a tool for assessing the surveillance of animal diseases: example of foot-and-mouth in Cambodia] (Timothée Vergne).

François Roger will also be chairing a session. Sophie Molia and Flavie Goutard will be taking part in a workshop on the terminology used in epidemiological surveillance and in a round table during the conference, while a training course in capture-recapture techniques for epidemiological surveillance, led by Vladimir Grosbois and Timothée Vergne, is scheduled at the Ecole Normale Supérieure de Lyon on 16 May.

Category: Coming up