A sensitive and specific antigen detection assay for Middle East respiratory syndrome coronavirus

Chen, Yixin; Chan, Kwok-Hung; Kang, Yahong; Chen, Honglin; Luk, Hayes KH; Poon, Rosana WS; Chan, Jasper FW; Yuen, Kwok-Yung; Xia, Ningshao; Lau, Susanna KP; Woo, Patrick CY

Protein concentration (log 10 ng/mL) TCID 50 (log 10 ) This antigen detection ELISA is suitable for clinical use and field studies in the Middle East where most cases of MERS have occurred. So far, most patients with MERS either resided in or had recent travel histories to the Middle East. Therefore, a MERS diagnostic test developed should be able to be used in clinical microbiology laboratories in the Middle East. As for the animal reservoirs, the infected dromedaries also live in the Middle East as well as North Africa. Compared to quantitative real-time RT-PCR, the consumable cost of the present antigen capture ELISA is lower. It also does not require expertise on molecular technology and the expensive set-up for molecular studies, which may not be present in most clinical microbiology laboratories in the Middle East. For example, about 15 million people, including more than two million pilgrims, visit Mecca in Saudi Arabia every year. In particular, a high concentration of visitors is expected during the Hajj period. A user-friendly laboratory test would be necessary for handling such a large number of exposed people as well as potential outbreaks because of mass gathering. Therefore, the present ELISA is likely to be more suitable than quantitative real-time RT-PCR for the use in laboratories in the Middle East and North Africa, where resources and expertise could be limited. As for animals, this test would be extremely useful for tracking the transmission patterns of MERS-CoV among the dromedaries in the same farm as well as across different countries. Further refinement of the test and the development of a rapid antigen detection kit for on-the-spot diagnosis are warranted.