Research projects to improve understanding of emerging pathogens that can be transmitted from animals to humans
Most pandemics are zoonotic in origin, in other words they are caused by pathogens able to spread between animals and humans. In order to anticipate and prevent zoonoses more effectively in the future, ANSES recently began coordinating two research projects. They are being rolled out in the context of the PEPR (Priority research programmes and facilities) initiative entitled Preventing Zoonotic Disease Emergence (Prezode), funded by the French National Research Agency under their France 2030 strategy. This programme aims to expand knowledge on zoonosis emergence in order to set up suitable strategies for epidemiological surveillance and prevention.
Instead: Improved surveillance and detection of the mosquito-borne West Nile and Usutu viruses
The Instead project focusses on two viruses vectored by mosquitos belonging to Culex genus: West Nile virus and the Usutu virus. These two viruses originate in Africa and affect mainly birds, but can also be transmitted to mammals - humans and horses in particular. The Usutu virus was detected in France for the first time in 2015, and West Nile virus has been present in the south of France since the 1960s, but until recently only affected humans and horses in Mediterranean regions. However, the risk has recently spread beyond this area to other geographical zones, with infections in humans and horses reported in 2022 for the first time in Nouvelle-Aquitaine, and several human and equine cases reported in Ile-de-France in the summer of 2025.
The project brings together 17 French laboratories working in the areas of human, animal and environmental health and is pursuing several goals:
- Develop innovative detection methods for early detection of the virus in the environment, including stagnant water, bird habitats, feathers and faeces, and in mosquitos,
- Set up a surveillance and management system involving the different players in human, animal and environmental health that is suited to the issues of each region,
- Improve understanding of how the virus is transmitted and identify new sentinel host species.
Ratswim: wastewater for monitoring rodent-borne pathogens
The second project, Ratswim, focusses on viruses and bacteria carried by rodents living near residential areas, as well as on the risks they pose to human health.
Rodents are reservoirs for a wide range of pathogens which can be transmitted to humans through environmental contamination. This project targets zoonotic viruses and bacteria presenting a high risk of emergence or reemergence, including:
poxviruses, including the mpox virus (formerlymonkeypox),
bacteria from the genus Leptospira, responsible for leptospirosis, whose incidence rate in France is among the highest in Europe,
the rat hepatitis E virus, occasionally responsible for cases of human hepatitis E.
One of the main objectives is to evaluate whether wastewater can be used for the detection these pathogens. This approach, already used for the surveillance of Sars-CoV-2 circulation in humans, would make it possible to replace current methods based on the capture of a limited number of animals, thus improving surveillance efficiency. The project also seeks to understand whether wastewater might contribute to the contamination of rodents. To do so, in vitro testing will be conducted to measure the infection capacity of viruses detected in wastewater.
Several ANSES laboratories are also involved in the HODAS project (Using population data to improve surveillance) with the support of INRAE. This project aims to strengthen the early detection of zoonotic pathogens by concentrating surveillance efforts on the animal populations that favour their emergence.