ABSTRACT
BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory illness in humans. Fundamental questions about circulating viruses and transmission routes remain. METHODS: We assessed routinely collected epidemiologic data for MERS-CoV cases reported in Saudi Arabia during 1 January-30 June 2015 and conducted a more detailed investigation of cases reported during February 2015. Available respiratory specimens were obtained for sequencing. RESULTS: During the study period, 216 MERS-CoV cases were reported. Full genome (n = 17) or spike gene sequences (n = 82) were obtained from 99 individuals. Most sequences (72 of 99 [73%]) formed a discrete, novel recombinant subclade (NRC-2015), which was detected in 6 regions and became predominant by June 2015. No clinical differences were noted between clades. Among 87 cases reported during February 2015, 13 had no recognized risks for secondary acquisition; 12 of these 13 also denied camel contact. Most viruses (8 of 9) from these 13 individuals belonged to NRC-2015. DISCUSSIONS: Our findings document the spread and eventual predominance of NRC-2015 in humans in Saudi Arabia during the first half of 2015. Our identification of cases without recognized risk factors but with similar virus sequences indicates the need for better understanding of risk factors for MERS-CoV transmission.
Subject(s)
Coronavirus Infections/epidemiology , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Adult , Aged , Aged, 80 and over , Cluster Analysis , Female , Humans , Male , Middle Aged , Middle East Respiratory Syndrome Coronavirus/classification , Middle East Respiratory Syndrome Coronavirus/genetics , Molecular Epidemiology , Phylogeny , Saudi Arabia/epidemiology , Sequence Analysis, DNA , Sequence Homology , Spike Glycoprotein, Coronavirus/genetics , Young AdultSubject(s)
Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Environmental Exposure , Middle East Respiratory Syndrome Coronavirus , Seasons , Animals , Camelus/virology , Coronavirus Infections/history , Coronavirus Infections/virology , Genome, Viral , History, 21st Century , Humans , Middle East Respiratory Syndrome Coronavirus/classification , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Phylogeny , Population Surveillance , Saudi Arabia/epidemiology , Whole Genome SequencingABSTRACT
During July-August 2015, the number of cases of Middle East respiratory syndrome (MERS) reported from Saudi Arabia increased dramatically. We reviewed the 143 confirmed cases from this period and classified each based upon likely transmission source. We found that the surge in cases resulted predominantly (90%) from secondary transmission largely attributable to an outbreak at a single healthcare facility in Riyadh. Genome sequencing of MERS coronavirus from 6 cases demonstrated continued circulation of the recently described recombinant virus. A single unique frameshift deletion in open reading frame 5 was detected in the viral sequence from 1 case.