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Note: The lancet report in this post was originally embargoed until 6:30 pm EDT today, but after an embargo break this morning by a UK newspaper (subsequently pulled), and follow up reportage by the AP and others, the Lancet announced late this afternoon that the embargo is now rescinded.
One of the mysteries surrounding the MERS coronavirus is exactly where it comes from. It is believed that it resides in some probably asymptomatic, but as yet unidentified animal host, and that it has only recently `jumped species’ to infect mankind.
Bats have been strongly suspected as being the main animal reservoir, but it is thought that a secondary (possibly amplifying) host, may have played a role in its spillover into humans.
In The Lancet tonight, we’ve the first serological evidence showing the the existence of antibodies that indicate prior exposure to MERS-CoV or to a MERS-like virus in Middle Eastern camels.
Led by by Dr Chantal Reusken, of the National Institute for Public Health and the Environment in Bilthoven (the Netherlands), an international team of researchers analyzed 349 blood samples collected from various livestock species (including goats, sheep, cattle, & camels) from Oman, the Netherlands, Spain, and Chile.
They tested not only for antibodies specific to the emerging MERS coronavirus, but for antibodies to the 2003 SARS coronavirus, and the most commonly reported human coronavirus (HCoV-OC43) which is antigenically similar to a common bovine coronavirus.
Along the way they found no evidence of cross-reactivity between the MER-CoV, SARS, and HCoV-OC43 viruses. Making it unlikely that prior exposure to other coronaviruses would produce false positive reactions to the MERS-CoV specific antibody test.
While no MERS-CoV antibodies were detected among the 160 cattle, sheep, and goat samples gathered from the Netherlands and Spain, specific antibodies to the MERS coronavirus were detected in all 50 of the dromedary camel samples gathered (from multiple locations) in Oman.
Additionally, much lower levels of antibodies were detected in 14% of camels from two dromedary herds tested from the Canary Islands.
This indicates is that MERS-CoV or a very similar virus, has infected dromedary populations in the Middle East in the recent past. The finding of very high antibody titers and 100% seroprevalence among Omani camels is actually quite remarkable.
What role (if any) that camels play in the transmission of the virus to humans has not been established. There may well be other animal hosts, not yet identified, that also carry the virus in the region.
Today’s study adds incrementally to what we already know (or think we know) about this virus, but we are still a long way from understanding it.
The authors call for additional studies to confirm their findings and to establish their possible relevance to human MERS-CoV infections.
For more on this, Helen Branswell’s report is now online, which you can read at:
By Helen Branswell The Canadian Press
And Jennifer Yang, has excellent coverage as well:
The Middle East respiratory syndrome — or MERS — has now infected 94 people and killed 46. Camels are being considered as a possible culprit.
The link to the Lancet report has not yet gone live. When it does, I’ll update this blog post. UPDATED
Chantal B E M Reusken*, Bart L Haagmans*, Marcel A Müller*, Carlos Gutierrez, Gert-Jan Godeke, Benjamin Meyer, Doreen Muth, V Stalin Raj, Laura Smits-De Vries, Victor M Corman, Jan-Felix Drexler, Saskia L Smits, Yasmin E El Tahir, Rita De Sousa, Janko van Beek, Norbert Nowotny, Kees van Maanen, Ezequiel Hidalgo-Hermoso, Berend-Jan Bosch, Peter Rottier, Albert Osterhaus, Christian Gortázar-Schmidt, Christian Drosten, Marion P G Koopmans