Comparison of laboratory methods used for identification of the first imported case of Middle East Respiratory Syndrome infection in China, 2015

Abstract

Objective To confirm the first imported case in China of Middle East respiratory syndrome(MERS) virus infection using various reliable laboratory diagnostic method. Methods One whole blood sample and three pharyngeal swabs were collected from a Korean patient in Guangdong Province, who was suspected as having MERS. Four in-house real-time RT-PCR assays targeting upE/ORF1a/N2/N3 gene of MERS virus were applied to validate the MERS-coronavirus (MERS-CoV) infection. The performance of the four in-house real-time RT-PCR assays was compared. Two kits for MERS-CoV detection were also validated using pharyngeal swab specimens. Results Three pharyngeal swabs from the first imported case of MERS in China were confirmed as positive for MERS-CoV by all the in-house assays, while the whole blood samples were detected as positive only using assays targeting N2/N3 gene. Both kits showed performance similar to that of corresponding in-house real-time RT-PCRassays. Conclusion The first imported case was confirmed as MERS-CoV infection by four in-house real-time RT-PCR assays targeting upE/ORF1a/N2/N3 gene. The assays targeting N2/N3 gene showed higher sensitivity than thosetargeting other genes, and therefore, the assays targeting N2/N3 are better choices for screening of MERS-CoV infection among clinical specimens. Key words: Middle East respiratory syndrome; Reverse trascriptase polymerase chain reaction reaction