Paradigm Shift Intervention Monitoring
twitter
Commentary
MERS Jeddah Camel and Case Match Concerns
Recombinomics Commentary
14:00
November 12, 2013
The above comments from the Kingdom of Saudi Arabia Ministry of Health (KSA-MoH) website strongly suggest that the PCR positive on a sample from a camel belonging to a MERS confirmed case (43M) was based on the same assay used to detect MERS-CoV in humans. These probes are based on human MERS sequences and designed to be specific for the beta 2c coronavirus linked to human cases. Sequences from these cases are >99.5% identical to the consensus sequence, and higher for clade B sequences which are present in all human cases due to infections following the first confirmed case, 60M in July, 2012.
In contrast, beta 2c sequences from bats come from a research protocol which uses a universal probe designed to detect all coronavirus. Thus, most bat coronavirus sequences are not beta 2c, and for those that are, the identity with the human sequences is < 92.5%, with the exception of a sequence from an Egyptian Tomb bat in Bisha, which was 100% identical to one of the sequences (EMC/12) from the first confirmed case, who was from Bisha (but was treated and died in Jeddah). Thus, the other bat beta 2c sequences are decades or centuries away from the human sequences. However, be one bat sequence which matches the human case in Bisha is found in Egyptian tomb bats, which are localized to the area around Bisha and therefore would not be linked to the vast majority of human cases in KSA. Moreover, the bat sequence matches the clade A sequence which has not been detected in humans since July, 2012.
Moreover, recent sequence data indicate the infection in July 2012 involved at least two distinct MERS-CoVs. The second sequence (Bisha-1) was clade B and had a 17 BP deletion, which was also detected in the first confirmed case (45M gym teacher) in Riyadh. Moreover Riyadh_1 was almost identical to Bisha_1 even though it was from an infection in Riyadh which had a disease onset date that was four months after the Bisha case.
These data discount to role of Egyptian tomb bats in cases in KSA, although this species is much more common in Egypt, Sudan, and India, raising the possibility that these species acts as an animal reservoir in those countries.
However, camels are more likely to be a source for human infections, base on MERS-like antibodies found at high titers and frequencies in racing camels in Oman as well as camels imported from Sudan for slaughter in Egypt. The PCR positive camel in Jeddah strongly suggests the sequence will be virtually identical to the recent Jeddah case (43M), who owns the camel and this identity will greatly increase the likelihood that the MERS-like antibodies in the above camels are due to a MERS-CoV infection (and not due to beta 2c sequences similar to other bat beta 2c sequences).
Thus, a sequence match in the Jeddah camel with accelerate research into the distribution of MERS-CoV in camels as well as viral concentrations in various samples collected from infected camels throughout the Middle East. These camel studies will also be used to determine the direction of the inter-species transmission (C2H or H2C or both), which will shed light on the role of camels in the frequency of MERS cases.
Recombinomics
Presentations
Recombinomics
Publications
Recombinomics
Paper
at Nature Precedings