Abstract EN:

Five human coronaviruses have been identified: HCoVs 229E, OC43, NL63, HKU1 and SARS-CoV. Among them, three have been found very recently: SARS-CoV in 2003, HCoV-NL63 in 2004, and HCoV-HKU1 in 2005. Human coronaviruses (except for SARS-CoV) mainly cause acute respiratory tract illnesses. They are also involved in enteric and neurological diseases. We have developed molecular methods to detect and characterize the HCoVs (except for SARS-CoV). These methods allow us to identify an outbreak of HCoV-OC43 respiratory infections, as well as the circulation and the genetic diversity of HCoVs NL63 and HKU1. The genetic diversity of HCoV-OC43 has been the foc us of more elaborate studies. The molecular and phylogenetic analysis of the S1 gene of seven HCoV-OC43 strains has shown a great inter-strain genetic diversity. We have demonstrated the quasispecies organization of the HCoV-OC43 viral population in a context of acute respiratory infection. The intra-strain genetic heterogeneity is very important. The demonstration of quasispecies distribution of HCoV-OC43 could provide a better understanding of the evolution of coronaviruses, especially their capacity to jump species barriers, to adapt to their new host, and to establish persistent infections.