Ecoepidemiology of coronaviruses, from wildlife to the human population, and assessment of the emerging potential – EPICOREM

More than 60% of infectious diseases in humans are caused by pathogens likewise circulating in domestic animals and wildlife. Most of these pathogens are viruses whose genome is an RNA molecule. RNA viruses are characterized by their genetic diversity, a population structure in quasispecies, a high level of recombination, the ability to establish persistent infections, and the ability to cross species barriers and to quickly adapt to environmental changes. Among RNA viruses, coronaviruses (CoVs) are unique in that, on the one hand, they seem to have a significant resistance despite their nature as enveloped viruses, and on the other hand, they have the largest known RNA genome. CoVs infect many mammalian and avian species, and a number of cases of successful emergence that have resulted from a crossing of the species barrier, have been documented in veterinary medicine. Special interest in human medicine has been given to CoVs since the outset of the SARS pandemic in 2002-2003, a result of crossing the species barrier starting from a reservoir of wild bats.
One of the main features of the EPICOREM project is its implication in current events. Four human CoVs currently circulate in humans and are responsible for respiratory infections of varying severity. Current studies show that HCoVs, along with Rhinoviruses, are the two most prevalent respiratory viruses in the general population, and among the most prevalent in the population of patients hospitalized for a respiratory infection. Very recent identification (September 2012) of HCoV-EMC, a highly pathogenic CoV with a mortality rate of over 50% among the 9 cases now described subjects CoVs to close monitoring. An HCoV-EMC alert is underway, particularly in the countries of the Arabian Peninsula, which places our study in the midst of current problematics.
The EPICOREM project also adheres to the innovative “One Health” approach, working from a broader, holistic vision of viral ecology within different ecosystems. It proposes a horizontal study of CoV infections reaching from wildlife to humans. This project also encompasses many aspects of coronaviral ecology: evaluation of circulation in different human and animal populations, the study of the diversity of CoV strains circulating in populations where CoV screening is performed, the study of CoVs in animal populations where no data are available, the study of key factors in transmission between hosts, the conditions of adaptation of the virus to various constraints (bottleneck, pre-existing immunity, anti-viral molecules). Improved knowledge of the ecology of viruses will clearly allow for a better understanding of the dynamics of CoV infections in various animal and human populations, and thus the rapid and early detection of emerging variants that are particularly pathogenic.
The multidisciplinary ambition of this project has brought together researchers involved in a wide range of disciplines: human virology, animal virology, evolutionary biology, phylogenetics, zoology, ecology, epidemiology, and immunology. Such a team of specialists allows for a guarantee of feasibility in that the acquisition of samples relevant to the interpretation of epidemiological and phylogenetic results are obtained. The current urgency as well as the innovative quality of the EPICOREM project will prove attractive to French experts on coronaviruses, and other experts in wildlife, and enable complex cross-referencing and data verification within the consortium established.