We’ve not seen anywhere near the number of MERS cases this year as we did during the spring of 2014, but we continue to see sporadic reports – mostly from Saudi Arabia – but also from Iran and now the UAE. Today’s notification is of an asymptomatic truck driver who was tested after some camels he was transporting from Oman tested positive for the virus.
This is only the second UAE MERS case reported in 2015, with the first being a fatal case last February.
In Lancet: Camels Found With Antibodies To MERS-CoV-Like Virus we saw a study showing specific antibodies to the MERS coronavirus in all 50 (100%) dromedary camel samples gathered (from multiple locations) in Oman, indicating past infection.
While most have antibodies, since camels clear the virus fairly quickly, most camels are not actively infected at any given time.
Since one of the unknowns with the MERS coronavirus is how it is being transmitted in the community, finding and studying asymptomatic (yet PCR positive) cases is of particular interest. It is unknown whether asymptomatic cases can spread the virus on to others, but some studies have suggested it is possible (see Study: Possible Transmission From Asymptomatic MERS-CoV Case).
Also unknown is how many asymptomatic (or mildly symptomatic) cases go undetected. Testing of asymptomatic contacts of known cases has turned scores of them, however.
In November of 2013, we looked at a study published in The Lancet Infectious Diseases, that attempted to quantify the likely extent of transmission of the MERS virus in the Middle East. (Middle East respiratory syndrome coronavirus: quantification of the extent of the epidemic, surveillance biases, and transmissibility).
They calculated that for every case identified, there were likely 5 to 10 that went undetected.
While only an estimate, this is in line with studies of other novel viruses that seek to estimate uncounted cases. And if true, would provide a plausible answer as to how hundreds of people – without obvious exposures – continue to contract the virus in the community.
Here is today’s report from the World Health Organization.
Disease outbreak news
18 May 2015
On 13 May 2015, the National IHR Focal Point of the United Arab Emirates (UAE) notified WHO of 1 additional case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection.
Details of the case are as follows:
A 29-year-old, non-national male from Abu Dhabi tested positive for MERS-CoV on 12 May. The patient works as a truck driver and frequently transports camels from Oman to UAE. He travelled to Ibri city, Oman on 6 May and transported camels to Abu Dhabi on 9 May. As part of the national policy of testing all imported camels for MERS-CoV, on 9 May, laboratory examinations were carried out on the camels that the truck driver was transporting. The animals tested positive for MERS-CoV on 10 May. This triggered an investigation of the truck driver, which started on the same day. Following hospital admission, the patient tested positive for MERS-CoV on 12 May. He was asymptomatic at the time of laboratory testing. The patient has no comorbidities and no history of exposure to other known risk actors in the 14 days prior to detection. Currently, he is asymptomatic in a negative pressure room on a ward.
Contact tracing of household contacts and healthcare contacts is ongoing for the case. The National IHR Focal Point of the United Arab Emirates informed the National IHR Focal Point of Oman to undertake the necessary investigation back in Oman.
Globally, WHO has been notified of 1118 laboratory-confirmed cases of infection with MERS-CoV, including at least 423 related deaths.
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