“Culicoides are small midges responsible for the transmission of viruses to domestic and wild ruminants with significant economic impacts on animal movements,” explains Claire Garros, a researcher specializing in these insects at CIRAD.
Between 2009 and 2017, CIRAD was mandated by the Directorate General for Food (DGAL)** to coordinate the surveillance of populations of Culicoides in mainland France. Since then, research teams from the Cirad-INRAE ASTRE unit have been supporting scientific and technical expertise on these vector midges and the risk of transmission of viruses transmitted to livestock.
“After an initial health crisis of bluetongue between 2002 and 2012 in metropolitan France, the emergence of the Schmallenberg virus in 2011 on the continent and the re-emergence of bluetongue in 2015, France is once again facing three fronts of emergence”expose Claire Garros.
An episode of FCO started in August 2023 in the south of the Massif Centralcausing mortality in cattle and sheep. After analysis, the ANSES National Reference Laboratory concluded that it was a variant of serotype 8 of FCO for which the vaccine remains effective. Thus, two strains of serotype 8 are present in mainland France, serotype 8 and its variant. The new strain has since spread and has been the cause of clinical cases observed in mainland France, particularly in the Pyrénées-Orientales, Aude and Ariège. These detections are characterized by serious clinical cases and high mortality. In response to these outbreaks, CIRAD organized three entomological missions to assess the abundance level of the populations of Culicoides on the altitudinal gradient and refute the presence of a species with Afrotropical and Mediterranean distribution, Culicoides imicolawhich colonized a small territory in the Pyrénées Orientales department between 2008 and 2011. The analysis of the captures is still in progress but we are already observing high abundances for capture sites at altitude. “, explains Maxime Duhayon, senior technician in entomology at CIRAD.
At the same time, South-west France is facing outbreaks of epizootic haemorrhagic disease (EHD) for the first time since September 2023 with strong health impacts on cattle. “The disease has been progressing since 2022 in the Iberian Peninsula and in the Italian islands (Sicily, Sardinia) with an origin of the North African introduction. There was no vaccine for this virus, but in August 2024, a vaccine obtained a temporary authorization for use (ATU)”, reveals Carlène Trevennec, INRAE research engineer, co-facilitator of international health monitoring.
The ministerial decree of October 25, 2023 sets out surveillance, prevention and control measures for epizootic hemorrhagic disease with the establishment of a regulated zone in all municipalities located within a perimeter of 150 kilometers around the declared outbreaks. Cattle, sheep, goats or deer from establishments located in the regulated zone may not leave this zone, except for exemptions. Animal management measures are also recommended, such as the disinfestation of animals or transport vehicles. There is no miracle vector control method against Culicoides. Current tools have limitations and do not provide total individual protection. Disinfestation is a complementary tool to vaccination when available. “. CIRAD is working with the Regional Federation of GDS AURA to study the practices and impact of insecticide treatments during animal movements.
The last front of emergence which affected France in August 2024 concerns serotype 3 of the bluetongue. The epizootic began in the Netherlands around September 2023, with rapid circulation throughout the country. The virus was then detected in Belgium, Germany, the United Kingdom, and recently in Luxembourg, Denmark and Switzerland. To date, around 340 outbreaks have been recorded in the north-eastern quarter of France with a voluntary vaccination campaign to limit the impacts of the disease.
As part of the VECTOCLIM project (VECTOr-borne diseases and CLIMate change in Occitanie, RIVOC project coordinated by the University of Montpellier, with funding from the Occitanie Region), CIRAD is developing models of population dynamics Culicoides and epidemiological models to assess the impact of recent and future global warming on the transmission of viruses transmitted by Culicoides. “Based on entomological data collected since 2009 by CIRAD and its partners, and data from the literature, I am developing a model of temporal and spatial dynamics of populations of Culicoides. This model aims to better understand potential changes in seasonal activity and population abundance of Culicoides Europeans under different climate scenarios”, presents Pachka Hammami, a researcher from the University of Montpellier hosted at CIRAD in the Astre unit.
Finally, to support health stakeholders and partners in the management of these three epizootics, CIRAD participates in the working groups of ANSES and the ESA platform as well as in the scientific and technical expert reports issued by ANSES, at the request of the Ministry of Agriculture, and supports the recommendations in terms of vector control measures and epidemiological surveillance.
*The international health monitoring of the ESA platform
The national animal health epidemiological surveillance platform (ESA platform) provides methodological and operational support to the competent State services and other managers of surveillance systems for the design, deployment, management, promotion and evaluation of health and biological surveillance systems in French territory.
It includes a international health monitoring, co-hosted by INRAE and Anses – which aims to identify, analyze and monitor signals relating to health hazards threatening French territory in animal health.
The production process includes monitoring of national and international signals. It is conducted on the basis of official and unofficial data sources. A multidisciplinary network of national and international experts (Anses, Cirad, DGAL, INRAE) is mobilized to sort, analyze and contextualize these signals. The analysis of these signals relating to health hazards leads to the drafting of weekly international health monitoring bulletins.
For more information: International health monitoring | ESA PLATFORM (plateforme-esa.fr)
Learn more about the ESA Platform member organizations :
Culicoides are responsible for the transmission of viruses to domestic and wild ruminants © J.-B. Ferré, EID-Méd
The CIRAD is the French agricultural research and international cooperation organization for the sustainable development of tropical and Mediterranean regions. With its partners, it co-constructs knowledge and solutions for resilient agriculture in a more sustainable and inclusive world. It mobilizes science, innovation and training to achieve the Sustainable Development Goals. It places its expertise at the service of everyone, from producers to public policies, to promote the protection of biodiversity, agroecological transitions, the sustainability of food systems, health (of plants, animals and ecosystems), the sustainable development of rural areas and their resilience to climate change. Present on all continents in around fifty countries, CIRAD relies on the skills of its 1,800 employees, including 1,240 scientists, as well as on a global network of 200 partners. It supports France’s scientific diplomacy.
INRA, The National Research Institute for Agriculture, Food and the Environment is a major player in research and innovation. The institute brings together a community of 12,000 people, with 272 research, service and experimentation units located in 18 centers throughout France.
A finalized research institute, it is positioned among the world’s leading research organizations in agricultural and food sciences, plant and animal sciences, and ecology-environment. It is the world’s leading research organization specialized in all
“agriculture-food-environment”. INRAE aims to be a key player in the transitions needed to respond to major global challenges.
Faced with population growth and the challenge of food security, climate change, the scarcity of resources and the decline in biodiversity, the institute has a major role in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.
