Seasonal Influenza in Morocco

Influenza is an acute respiratory infection caused by influenza viruses of the Orthomyxoviridae family. Influenza virus cell culture consists of inoculating viral isolates on an MDCK cell layer. The objective of this work is to describe the role of cell culture in influenza virus subtyping during the 2023/2024 influenza epidemic at the Mohammed V Military Teaching Hospital - Rabat. This is a prospective descriptive study carried out at the Virology laboratory of the HMIMV in Rabat, during the 2023/2024 influenza epidemic season (between October and May). It included all samples from patients positive for influenza viruses by the respiratory PCR test. Of the 86 samples positive by PCR, 36 were selected for viral culture. Cell culture allowed the isolation of the virus from the original sample, thus producing a sufficient quantity for further antigenic and genetic characterization, allowing the subtyping of circulating strains. The results showed a predominance of influenza A(H3N2) with 35 cases out of 36 compared to influenza A(H1N1) pdm09 with only 1 case. Cell culture also makes it possible to assess the sensitivity of isolated viral strains to antiviral molecules and to detect the emergence of resistance. Thus, it plays an important role in virological surveillance and in alerting to the event of the appearance of new viruses.