1 www.eurosurveillance.org Rapid communications Middle East respiratory syndrome coronavirus (MERS- CoV) in dromedary camels, Oman, 2013 N Nowotny (Norbert.Nowotny@vetmeduni.ac.at) 1,2 , J Kolodziejek 1 1. Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria 2. Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman Citation style for this article: Nowotny N, Kolodziejek J. Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels, Oman, 2013. Euro Surveill. 2014;19(16):pii=20781. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20781 Article submitted on 17 April 2014 / published on 24 April 2014 A countrywide survey in Oman revealed Middle East respiratory syndrome coronavirus (MERS-CoV) nucleic acid in five of 76 dromedary camels. Camel-derived MERS-CoV sequences (3,754 nucleotides assem- bled from partial sequences of the open reading frame (ORF)1a, spike, and ORF4b genes) from Oman and Qatar were slightly different from each other, but closely related to human MERS-CoV sequences from the same geographical areas, suggesting local zoonotic transmission. High viral loads in nasal and conjunctival swabs suggest possible transmission by the respiratory route. Background In June 2012 a novel betacoronavirus, subsequently named Middle East respiratory syndrome coronavirus (MERS-CoV), was isolated from a patient with fever and respiratory symptoms who had been admitted to a hos- pital in Jeddah, Saudi Arabia [1]. As of 22 April 2014, the number of reported laboratory-confirmed cases of MERS-CoV worldwide amounts to 333, with 107 deaths [2]. To date, only fifteen cases, including ten in Europe, have been reported outside of the Middle East [2] and the vast majority of cases were reported from Saudi Arabia. Thus, it seems that the virus may originate from the Arabian Peninsula. Family, healthcare associ- ated and community case clusters of MERS-CoV infec- tions have been reported (e.g. [3]). Besides limited human-to-human transmission, how- ever, epidemiological data point towards an animal reservoir of MERS-CoV. First evidence of such a reser- voir host was provided when all 50 investigated sera of dromedary camels (Camelus dromedaries) from Oman exhibited high-titre neutralising antibodies against MERS-CoV [4]. This observation has meanwhile been confirmed by several studies from other countries on the Arabian Peninsula and beyond (e.g. Egypt [5]). Other important farm animals on the Arabian Peninsula such as cattle, goats, sheep and chickens were also inves- tigated but were found negative [6,7]. Although differ- ent species of bats carry a variety of coronaviruses and have been suggested as the most likely primary animal reservoir for MERS-CoV, so far only a short (190 nucleo- tides (nt)) sequence in a conserved region of the MERS- CoV genome was amplified from a faecal pellet of a bat (Taphozous perforates) in Saudi Arabia [8]. The present study was initiated in order to identify the virus in cam- els and to compare it genetically with human-derived MERS-CoV. Sample collection In December 2013, nasal and conjunctival swabs were taken from 76 dromedary camels of different age, breed and sex from all over Oman. All swabs were taken in duplicates, one stored in virus isolation medium and the other in the virus-inactivating buffer DNA/RNA Shield (Zymo Research, Irvine, USA). The former samples were frozen at -80°C at the Veterinary Research Center of the Ministry of Agriculture and Fisheries, Oman, for later use, while the latter samples were shipped to the University of Veterinary Medicine Vienna for analysis. DNA/RNA Shield effectively lyses cells and inactivates nucleases and infectious agents. In addition it ensures nucleic acid stability during sam- ple storage and transport at ambient temperatures. Nucleic acid extraction and polymerase chain reactions RNA was extracted employing a Quick-RNA MiniPrep Kit (Zymo Research, Irvine, USA), following the manu- facturer’s instructions. For screening, two published MERS-CoV reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays were performed, one in the open reading frame (ORF)1a gene region [9] and the other in the ORF1b gene region [10], and both were optimised for SuperScript III Platinium One-Step RT-qPCR System (Invitrogen/LifeTechnologies, CA, USA). For confirma- tion, the positive samples were retested by reverse transcription-polymerase chain reactions (RT-PCRs) in the RNA-dependent RNA polymerase (RdRp)- and nucle- ocapsid (N) gene regions [9] as well as in the spike