MERS-coronavirus: From discovery to intervention

Widagdo, W.; Okba, Nisreen M.A.; Stalin Raj, V.; Haagmans, Bart L.

Upon its discovery, MERS-CoV was found to replicate to high titers and induce cytopathic effects in various different cell lines, thus enabling its rapid full genome characterization [3, 8] . Two large replicase open reading frames, ORF1a and ORF1b cover the 5′ region of the MERS-CoV genome, whereas the 3′ end of the genome encodes structural proteins, i.e. spike (S), membrane (M), nucleocapsid (N), envelope (E), and several accessory proteins (3, 4a, 4b, 5 and 8b). The nucleotide sequence of MERS-CoV was used as a template to design primers for genome-based assays, i.e. real-time reverse-transcription polymerase chain reaction (RT-PCR) and sequencing [9, 10] . Primer pairs targeting a region upstream of E (upE), N, ORF1a, ORF1b and RdRp genes were then developed and shown to be highly sensitive and specific not only for the EMC isolate but also for other MERS-CoV isolates [9] [10] [11] . It is currently suggested to use upE RT-PCR as a screening assay and another target gene as a confirmatory assay [11] .