Virus syncytial respiratoire et virus para-influenza humains : épidémiologie

Respiratory syncytial virus (RSV), parainfluenza virus (PIV), and human metapneumovirus (hMPV) are members of the Paramyxoviridae family. These pleomorphic viruses have an RNA containing about ten genes and a lipid envelope covered with glycoprotein projections that bind the virus particle to the cell membrane then ensure penetration of the virus within the cell. Although these viruses induce neutralising antibodies that play a major role in combating the infection, the virus-infected cells are eliminated by the cell-mediated immune response. RSV infections occur regularly each year as winter outbreaks that peak in December or January. The incidence of RSV-related bronchiolitis has increased significantly over the last 10 years. VPI3 is endemic and causes infections from September through March, whereas VPI1 and VPI2 are less common and manifest mainly as small irregular outbreaks, often in the autumn. Finally, hMPV is responsible for outbreaks that coincide with RSV outbreaks but are far more limited.