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Commentary
Qatari Camel MERS Sequences Re-Confirmed
Recombinomics Commentary
16:15
December 2, 2013
Osterholm praises Qatar for its efforts. "The public health officials in Qatar deserve a great deal of credit for their aggressive actions in investigating this situation and involving the relevant international laboratory partners," he says. "This could have been done in Saudi Arabia months ago."
The above comments on MERS sequences in a Qatar camel confirm that the PCR test identifies MERS-CoV. This identification was expected because of the specificity of the MERS PCR test, but the camel cluster has generated significant confusion, including statements about MERS-like antibodies found in camels in Oman and Egypt. Although the antibody data only suggests that the coronavirus infections were due to beta2c, the PCR result in Qatar and Saudi Arabia increase the likelihood that the earlier antibody results were in fact due to prior MERS-CoV infections.
The additional comments on progress in the Kingdom of Saudi Arabia (KSA) highlight concerns that testing of camels in KSA has been lacking. Recently a symptomatic camel owned by a MERS confirmed Jeddah case was PCR confirmed. Sequences from the camel and case were expected last week, but the identity between the two sets of sequences is expected to be close to 100% (>99.9%). The identity between the KSA sequences or sequences from the Qatari camels and linked confirmed human cases (61M & 23M), will confirm interspecies transmission, but will not determine the direction.
The direction of transmission is largely dependent on more serious surveillance in KSA and throughout the Middle East. The index case of a cluster in Batin had cared for a symptomatic camel, but there are no reports on the testing of the camel. Dr Ziad Memish had defended that lack of animal testing due to the absence of a protocol from WHO. However, media reports noted that the PCR confirmation of the camels in Qatar (who were either asymptomatic or had mild symptoms) used a nasal swab, which could be collected by veterinarians and testing would follow the protocol used for swabs from humans.
The presence of MERS in camels throughout the Middle East (as indicated by antibody positives in Oman and Egypt or MERS PCR positive in KSA or Qatar) raises serious concerns because of the potential for ongoing jumps from camels to humans and subsequent adaptation to humans. The lack of serious surveillance has delayed a determination of the extent of MERS spread throughout the camel population and the ability to control this potentially significant reservoir.
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