Use of Dorylus army ants in virome characterization of the African rainforest ecosystem and in viral zoonotic diseases surveillance – MAGNAN

The unpredictable outbreaks that recently emerged from tropical forest's wildlife highlight a tremendous lack of knowledge about viruses that circulate within such ecosystems. Indeed, only about 1% of eukaryotic viruses present on earth have been identified, which would constitute a major obstacle to the early detection and rapid control of any new epidemic event. However, detection and characterisation of animal and plant’s hosted viruses in a given ecosystem require provision of massive biological samples which is extremely difficult in these dense and hostile ecosystems where animal species are often inaccessible. It is therefore critical to identify new strategies and approaches for exploring viral ecology. To this end, the MAGNAN project proposes to use Dorylus army ants as an innovative and indirect wildlife’s sampling strategy. Hence, army ants figure amongst major arthropod predators and are considered to be key species in tropical forest ecosystems. Large nomadic colonies constituted of thousands of workers move, making spectacular raids on the ground, hunting and overwhelming a very wide range of live invertebrate and vertebrate preys in large quantities, but also scavenging animal carcasses or feeding directly on plants. Based on convincing preliminary results obtained by viral metagenomics methods, we have shown that army ants can accumulate large amounts of genomic sequences of vertebrate, invertebrate and plant’s hosted viruses. The project aims at providing better understanding of virome in tropical forest ecosystems as well as implementing a new, ground-breaking and non-invasive strategy for surveillance of viral zoonoses in environments where spillovers are frequent. This project represents a proof of concept that may pave the way towards large scale studies on all tropical forest ecosystems’ virome. It stands at the forefront of an innovative research field focused on virus ecology and emergence in One Health and Eco Health perspectives.