Rapid and sensitive identification of the A/AFRICA/G-IV lineage of FMD by a novel Real-time RT-PCR assay
Résumé
Genetic characterization of foot-and-mouth disease virus (FMDV) lineages circulating in affected countries is critical for the epidemiological surveillance and for the implementation of appropriate control measures of the disease. In 2017, for the first time since 1977, a serotype A FMDV was detected at the gates of Europe, in Algeria and Tunisia. After sequencing of the VP1-coding region, the outbreak virus was identified as belonging to the topotype Africa and lineage G-IV (A/Africa/G-IV). Here, we present the development of a real-time RT-PCR assay able to identify the A/Africa/G-IV lineage of FMDV. The design of the assay was performed in silico to discriminate viruses of interest from other FMDVs of the same serotype and from other lineages circulating in the same geographical area. Our real-time RT-PCR assay detected all the A/Africa/G-IV samples tested (n=7). A representative panel of other FMDV lineages, including all that co-circulate with A/Africa/G-IV (n=30) were not detected. Our lineage-specific real-time assay presents an efficiency of 97% and a detection limit of 100 RNA copies. Our test therefore allows, with a two hours PCR, the specific identification of the A/Africa/G-IV lineage with an affordable set-up performed in-house, at a significantly lower cost than sequencing methods. Overall, these data indicate that this newly developed real-time RT-PCR assay can be applied to characterize field isolates in countries where the A/AFRICA/G-IV lineage is endemic, as well as to monitor new incursions of this lineage in exotic locations.