MERS-CoV KSA Clonal Expansion Raises Concerns
June 15, 2013
The Kingdom of Saudi Arabia Ministry of Health (KSA-MoH) in association with the Welcome Trust have released four full MERS-CoV sequences (Al Hasa 1/2013, Al Hasa 2/2013, Al Hasa 3/2013, Al Hasa 4/2013) which increases the number of full sequences from 5 to 9 and the number of 2013 full sequences from 2 to 6. They are commended for the release of these important sequences. However, the number of unique sequences in each category only increased by one, because all four sequences from Al Hasa are virtually identical.
The sequences clearly represent clonal expansion in the hospital and linked contacts (see map) and the close relationship to England2/2013 strongly supports evolution of MERS-CoV in humans. However, it is unclear if these sequences now represent the dominant MERS-CoV sequence circulating in KSA at this time. The nosocomial outbreak in Al Hofuf was followed by another outbreak at another hospital in the eastern region of KSA, so sequences from that outbreak would be useful.
Moreover, these two outbreaks were followed by significant spread in the northern portion of the eastern region as well as recent cases in the central region as well as western KSA near Mecca.
The four full Illumina sequences indicate the KSA-MoH has the expertise to quickly generate full sequences for the recent cases. Release of a full set of sequences from these cases would be useful.